POP3 - Post Office Protocol version 3
What is POP3?
POP3 stands for Post Office Protocol version 3. It is a standard email protocol used to retrieve emails from a mail server to a local computer.
Why is POP3 useful?
POP3 downloads emails to our device, so we can read them even without an internet connection. It also helps free up space on the email server by deleting emails from the server after downloading (optional). POP3 is easy to configure and works with most email clients like Outlook, Thunderbird, etc.
How it works?
Email arrives at our mail server.
Our email client connects to the server using POP3.
It authenticates using our username and password.
The client downloads the emails from the server to our local device.
Depending on settings, it may delete the emails from the server.
We can now read emails offline on our device.
Where is POP3 used?
In personal email clients like Microsoft Outlook, Mozilla Thunderbird, etc.
When users prefer to store emails locally instead of keeping them online.
In low-bandwidth environments where constant internet access isn’t available.
Which OSI layer does POP3 belong to?
It provides name resolution services to applications and users.
POP3 is used by email client software to retrieve emails from the server.
It deals with data formatting, user authentication, and communication with the mail server, which are functions of the Application Layer (Layer 7).
What are the key features?
Download-and-Delete Model.
One Inbox Only.
Single-Device Oriented.
Pull-Based Communication.
Can POP3 be used with multiple devices?
Not efficiently. POP3 is designed for single-device use. Using it with multiple devices may cause: * Email duplication. * Inconsistent inboxes. * Missing messages.
What happens if the internet disconnects during retrieval?
Partial downloads may be lost.
Email might be redownloaded on the next connection.
If DELE hasn’t been processed, the email stays on the server.
How is retransmission handled in POP3?
If an ACK is not received within the timeout interval, POP3 retransmits the segment. Modern POP3 uses: * Timeout-based retransmission. * Fast retransmit (based on duplicate ACKs).
What are some applications that use POP3?
Email Clients (Desktop-Based).
Mobile Email Apps (With Manual Setup).
Automated Systems / Scripts.
Web-Based Services.
What is the working flow of POP3?
Email Client Connects to the Mail Server * The user opens an email app. * The client connects to the mail server on:
Port 110 (plain POP3).
Port 995 (POP3 over SSL/TLS).
Client Authenticates * The client sends: * USER - username * PASS - password * If correct, the server allows access.
Client Checks for Messages * The client asks how many messages are available: * STAT - gives number and total size. * LIST - lists each email with its size.
Client Downloads Emails * The client uses RETR <email_number> to download each email. * Emails are saved locally on the device (inbox folder or storage).
Client Ends the Session * The client sends: * QUIT - ends session and deletes emails marked by DELE. * Connection is closed.
When is POP3 preferred over IMAP?
Low-storage servers.
Offline access needed.
Single-device users.
Simple use cases (e.g., automated systems downloading logs).
Topics in this section,
In this section, you are going to learn
Terminology
Version Info
S.No |
Version |
RFC |
Year |
contribution/core ideas |
|---|---|---|---|---|
1 |
POP1 |
RFC 918 |
1984 |
The original version; very basic functionality for retrieving email. |
2 |
POP2 |
RFC 937 |
1985 |
Added more commands and structure; rarely used today. |
3 |
POP3 |
RFC 1081 RFC 1939 |
1988-1996 |
Most widely used version; supports authentication, message retrieval, and deletion. |
4 |
POP3 AUTH |
RFC 1734 |
1994 |
Adds support for the AUTH command to allow pluggable authentication methods. |
5 |
POP3 Extension Mechanism |
RFC 2449 |
1998 |
Introduces a way to extend POP3 with optional capabilities (e.g., UIDL, TOP). |
setup
setup
POP3 COMMAND LINE Packet
S.No |
Packet Components |
Description |
Size(Bytes) |
|---|---|---|---|
1 |
Command Line |
Text-based command sent by client to server where |
Variable(typically<512) |
cilent sends commands like USER, PASS,STAT,LIST etc. |
|||
Command Keyword |
POP3 command like USER, PASS, STAT, LIST, etc. |
Variable (typically < 10) |
|
Arguments |
Parameters for the command (e.g., username, message number) |
Variable. |
|
CRLF |
Carriage Return + Line Feed to terminate the command. |
2 |
POP3 RESPONSE LINE Packet
2 |
Response Line |
Server replies with +OK or -ERR followed by a message. |
Variable (typically < 512) |
|---|---|---|---|
Status Indicator |
Server response: +OK (success) or -ERR (error) |
34 |
|
Message Text |
Optional human-readable message |
Variable. |
|
CRLF |
Terminates the response line |
2 |
POP3 MESSAGE HEADER Packet
3 |
Message Header |
Metadata of the email (From, To, Subject, etc.) |
Variable (depends on email) |
|---|---|---|---|
Header Fields |
Email metadata: From, To, Subject, Date, etc. |
Variable. |
|
CRLF |
Separates each header line |
2 per line. |
POP3 MESSAGE BODY Packet
4 |
Message Body |
Actual content of the email message |
Variable (depends on email) |
|---|---|---|---|
Body Content |
Actual content of the email message |
Variable |
|
CRLF |
Line breaks within the message |
2 per line |
POP3 TERMINATION SEQUENCE Packet
5 |
Termination Sequence |
Ends multi-line responses with a single period (.) on |
3(CRLF +.) |
|---|---|---|---|
a line |
|||
End Marker |
A single period (.) on a line to indicate end of multi-line response |
3 (CRLF.) |
POP3 AUTHENTICATION DATA Packet
6 |
Authentication Data |
Username and password sent during login |
Underlying transport layer headers |
|---|---|---|---|
Username |
Sent with USER command |
Variable |
|
Password |
Sent with PASS command |
Variable |
|
CRLF |
Terminates each line |
2 |
POP3 TCP/IP HEADER Packet
7 |
TCP/IP Header |
Underlying transport layer headers |
40 (20 TCP + 20 IP) |
|---|---|---|---|
IP Header |
Contains source/destination IP, protocol, etc. |
20 |
|
TCP Header |
Contains source/destination port, sequence number, etc. |
20 |
S.No |
Use Case |
Description |
|---|---|---|
1 |
Email Retrieval |
POP3 allows users to download emails from a remote |
server to a local device. |
||
2 |
Offline Email Access |
Once downloaded, emails can be accessed, without |
an internet connection |
||
3 |
Simple Mail Clients |
Ideal for basic email clients that don’t require |
synchronization across devices. |
||
4 |
Archiving Emails Locally |
Enables users to store and manage emails on their |
own systems. |
||
5 |
Integration with Legacy Systems |
Useful in older systems that don’t support IMAP or |
modern protocols. |
||
6 |
Secure Email Access |
Can be used with TLS/SSL to ensure secure |
transmission of credentials and data. |
S.No |
POP3 features |
Description |
|---|---|---|
1 |
Simple Protocol |
POP3 uses a straightforward command-response mechanism over TCP. |
2 |
Email Download |
Allows users to download emails from the server to a local device. |
3 |
Offline Access |
Once downloaded, emails can be accessed without an internet |
connection. |
||
4 |
Server Cleanup |
Emails are typically deleted from the server after download. |
5 |
Limited Command Set |
POP3 supports a small set of commands, making it lightweight |
and easy to implement. |
||
6 |
Authentication Support |
Supports basic authentication using USER and PASS. |
7 |
Port-Based Communication |
Uses TCP port 110 (or 995 for POP3 over SSL/TLS). |
8 |
No Folder Support |
POP3 does not support server-side folders or message organization |
9 |
Optional TLS Encryption |
Can be secured using SSL/TLS for encrypted communication. |
Simple Protocol - Testcases
S.No |
Test Case |
Description |
Expected Result |
|---|---|---|---|
1 |
PoP3 Connection Establishment |
Establish connection to PoP3 server |
Connection established successfully |
2 |
PoP3 Authentication |
Authenticate user with username and password |
Authentication successful |
3 |
Invalid Credentials Handling |
Attempt login with invalid credentials |
Authentication failed |
4 |
PoP3 Port Validation |
Connect using default port 110 |
Connection successful |
5 |
PoP3 Secure Port Validation |
Connect using secure port 995 |
Secure connection established |
6 |
TLS Negotiation |
Initiate TLS for secure communication |
TLS handshake successful |
7 |
Retrieve Email List |
Fetch list of emails from server |
Email list retrieved |
8 |
Retrieve Specific Email |
Fetch specific email by ID |
Email content retrieved |
9 |
Delete Email |
Delete email from server |
Email deleted successfully |
10 |
Email Deletion Rollback |
Undo email deletion before session ends |
Email restored |
11 |
Session Timeout |
Test session timeout behavior |
Session terminated after timeout |
12 |
Multiple Sessions Handling |
Handle multiple sessions from same client |
Sessions managed correctly |
13 |
Concurrent Access |
Access mailbox concurrently |
Access synchronized |
14 |
Invalid Command Handling |
Send invalid PoP3 command |
Error response received |
15 |
Command Sequence Enforcement |
Enforce correct command sequence |
Commands executed in order |
16 |
PoP3 CAPA Command Support |
Check support for CAPA command |
CAPA response received |
17 |
PoP3 UIDL Command Support |
Use UIDL to fetch unique IDs |
Unique IDs retrieved |
18 |
PoP3 TOP Command Support |
Use TOP to fetch headers |
Headers retrieved |
19 |
PoP3 LIST Command Support |
Use LIST to get message sizes |
Message sizes listed |
20 |
PoP3 RETR Command Support |
Use RETR to retrieve message |
Message retrieved |
21 |
PoP3 DELE Command Support |
Use DELE to delete message |
Message deleted |
22 |
PoP3 QUIT Command Support |
Use QUIT to end session |
Session ended successfully |
23 |
PoP3 NOOP Command Support |
Use NOOP to keep session alive |
NOOP acknowledged |
24 |
PoP3 RSET Command Support |
Use RSET to reset session state |
Session state reset |
25 |
PoP3 STAT Command Support |
Use STAT to get mailbox status |
Mailbox status retrieved |
26 |
PoP3 Command Case Sensitivity |
Test case sensitivity of commands |
Commands accepted in correct case |
27 |
PoP3 Response Format Validation |
Validate format of server responses |
Responses formatted correctly |
28 |
PoP3 Error Message Clarity |
Check clarity of error messages |
Clear error messages received |
29 |
PoP3 Server Load Handling |
Test server under high load |
Server remains responsive |
30 |
PoP3 Server Restart Recovery |
Recover session after server restart |
Session re-established |
31 |
PoP3 Mailbox Locking |
Lock mailbox during session |
Mailbox locked |
32 |
PoP3 Mailbox Unlocking |
Unlock mailbox after session |
Mailbox unlocked |
33 |
PoP3 Message Integrity |
Ensure message integrity during retrieval |
Message content intact |
34 |
PoP3 Message Order Preservation |
Preserve order of messages |
Messages ordered correctly |
35 |
PoP3 Large Message Handling |
Retrieve large email message |
Message retrieved without error |
36 |
PoP3 Attachment Retrieval |
Retrieve email with attachment |
Attachment downloaded |
37 |
PoP3 HTML Email Support |
Retrieve HTML formatted email |
HTML content displayed correctly |
38 |
PoP3 Plain Text Email Support |
Retrieve plain text email |
Text content displayed correctly |
39 |
PoP3 Encoding Support |
Handle different encodings (UTF-8, ASCII) |
Encodings interpreted correctly |
40 |
PoP3 Internationalization Support |
Handle emails with international characters |
Characters displayed correctly |
41 |
PoP3 Spam Email Handling |
Retrieve spam-marked emails |
Spam emails retrieved |
42 |
PoP3 Email Header Parsing |
Parse email headers accurately |
Headers parsed correctly |
43 |
PoP3 Email Body Parsing |
Parse email body accurately |
Body parsed correctly |
44 |
PoP3 Server Compatibility |
Test compatibility with various PoP3 servers |
Compatible with all tested servers |
45 |
PoP3 Client Compatibility |
Test compatibility with various PoP3 clients |
Compatible with all tested clients |
46 |
PoP3 Logging Support |
Log PoP3 session activities |
Logs generated successfully |
47 |
PoP3 Audit Trail |
Maintain audit trail of email access |
Audit trail maintained |
48 |
PoP3 Security Compliance |
Ensure compliance with security standards |
Compliance verified |
49 |
PoP3 Performance Benchmarking |
Benchmark performance under normal load |
Performance within acceptable limits |
50 |
PoP3 User Experience Evaluation |
Evaluate user experience using PoP3 |
Positive user feedback |
Email Download - Testcases
S.No |
Test Case |
Description |
Expected Result |
|---|---|---|---|
1 |
Valid Login |
Login with correct credentials |
Login successful |
2 |
Invalid Password |
Login with wrong password |
Authentication failed |
3 |
Invalid Username |
Login with wrong username |
Authentication failed |
4 |
Empty Credentials |
Login with blank username/password |
Error message shown |
5 |
POP3 Port Default |
Connect using default port 110 |
Connection successful |
6 |
POP3 Port SSL |
Connect using SSL port 995 |
Secure connection established |
7 |
Invalid Port |
Connect using invalid port |
Connection refused |
8 |
Server Timeout |
Simulate server timeout |
Timeout error shown |
9 |
Download Single Email |
Download one email |
Email downloaded successfully |
10 |
Download All Emails |
Download all emails from inbox |
All emails downloaded |
11 |
Download Large Email |
Download email >10MB |
Email downloaded without corruption |
12 |
Download with Attachments |
Email with attachments |
Email and attachments downloaded |
13 |
Download HTML Email |
Email with HTML content |
HTML rendered correctly |
14 |
Download Plain Text Email |
Email with plain text |
Text displayed correctly |
15 |
Download Multipart Email |
Email with multiple parts |
All parts downloaded |
16 |
Delete After Download |
Enable delete after download |
Email removed from server |
17 |
Retain After Download |
Disable delete after download |
Email remains on server |
18 |
Check Email Count |
Count emails before download |
Correct count displayed |
19 |
Download from Empty Inbox |
No emails in inbox |
Message: No emails to download |
20 |
Interrupted Download |
Simulate network drop |
Resume or error message shown |
21 |
Reconnect After Drop |
Reconnect after disconnection |
Session resumes or restarts |
22 |
Concurrent Sessions |
Multiple clients access same account |
Handled gracefully |
23 |
Invalid Email Format |
Corrupt email format |
Error handled without crash |
24 |
POP3 Disabled |
Server with POP3 disabled |
Connection refused |
25 |
SSL Certificate Invalid |
Connect with invalid SSL cert |
Warning or connection blocked |
26 |
SSL Certificate Expired |
Expired cert on server |
Warning or connection blocked |
27 |
Authentication Required |
Server requires login |
Prompt for credentials |
28 |
No Authentication |
Server allows anonymous |
Connection established (if allowed) |
29 |
Email Header Only |
Download headers only |
Headers downloaded |
30 |
Email Body Only |
Download body only |
Body downloaded |
31 |
Email with Inline Images |
Email with embedded images |
Images rendered correctly |
32 |
Email with External Links |
Email with external content |
Links preserved |
33 |
Email with Special Characters |
Unicode or emojis in subject/body |
Displayed correctly |
34 |
Email with Long Subject |
Subject >255 characters |
Displayed without truncation |
35 |
Email with Long Body |
Body >1MB |
Fully downloaded |
36 |
Email with Nested MIME |
Complex MIME structure |
Parsed correctly |
37 |
POP3 Command Injection |
Inject POP3 commands in input |
Input sanitized |
38 |
Brute Force Login |
Multiple failed attempts |
Account locked or throttled |
39 |
POP3 Command Sequence |
Invalid command order |
Error returned |
40 |
LIST Command |
List all emails |
Correct list shown |
41 |
RETR Command |
Retrieve specific email |
Email retrieved |
42 |
DELE Command |
Delete specific email |
Email deleted |
43 |
QUIT Command |
End session |
Session closed |
44 |
STAT Command |
Get mailbox stats |
Correct stats shown |
45 |
UIDL Command |
Get unique IDs |
Unique IDs returned |
46 |
TOP Command |
Get top lines of email |
Partial content shown |
47 |
CAPA Command |
Check server capabilities |
Capabilities listed |
48 |
Invalid POP3 Command |
Send unknown command |
Error returned |
49 |
POP3 over IPv6 |
Connect using IPv6 |
Connection successful |
50 |
POP3 Logging |
Enable logging |
Logs generated correctly |
Offline Access - Testcases
S.No |
Test Case |
Description |
Expected Result |
|---|---|---|---|
1 |
POP3 Server Connection Offline |
Attempt to connect to POP3 server while offline |
Connection fails gracefully |
2 |
Cached Email Access |
Access previously downloaded emails offline |
Emails viewable without internet |
3 |
Email Header Display |
View email headers offline |
Headers displayed correctly |
4 |
Email Body Display |
View full email body offline |
Body displayed correctly |
5 |
Attachment Access |
Open attachments from cached emails |
Attachments open successfully |
6 |
Search Cached Emails |
Search through offline emails |
Search returns correct results |
7 |
Offline Email Sorting |
Sort emails by date, sender, subject offline |
Sorting works correctly |
8 |
Offline Email Filtering |
Apply filters to offline emails |
Filters applied successfully |
9 |
Offline Email Deletion |
Delete emails while offline |
Emails marked for deletion |
10 |
Sync Deleted Emails |
Sync deletions when back online |
Deletions reflected on server |
11 |
Compose Email Offline |
Compose new email while offline |
Email saved to outbox |
12 |
Send Queued Email |
Send email from outbox when online |
Email sent successfully |
13 |
POP3 Authentication Offline |
Attempt to authenticate while offline |
Authentication fails gracefully |
14 |
Email Draft Access |
Access saved drafts offline |
Drafts viewable and editable |
15 |
POP3 Port Configuration |
Use correct port for POP3 (110/995) |
Port accepted or rejected |
16 |
Offline Mode Toggle |
Switch client to offline mode manually |
Client enters offline mode |
17 |
Auto-Sync on Reconnect |
Automatically sync when internet is restored |
Sync starts automatically |
18 |
Manual Sync Trigger |
Manually trigger sync after reconnect |
Sync completes successfully |
19 |
Offline Email Flagging |
Flag emails while offline |
Flags saved and synced |
20 |
POP3 SSL/TLS Offline Handling |
Handle SSL/TLS settings offline |
No errors shown |
21 |
Offline Folder Navigation |
Navigate between folders offline |
Navigation works smoothly |
22 |
POP3 Server Timeout Offline |
Handle timeout errors gracefully |
User notified, no crash |
23 |
POP3 Server Retry Logic |
Retry connection after failure |
Retry logic works as expected |
24 |
POP3 Error Logging |
Log errors encountered offline |
Logs generated correctly |
25 |
POP3 Offline Sync Queue |
Queue sync actions while offline |
Queue maintained |
26 |
POP3 Offline Email Forwarding |
Forward cached email while offline |
Email queued for sending |
27 |
POP3 Offline Email Reply |
Reply to cached email while offline |
Reply queued for sending |
28 |
POP3 Offline Email Print |
Print cached email |
Email printed successfully |
29 |
POP3 Offline Email Export |
Export cached email to file |
Export completes successfully |
30 |
POP3 Offline Email Import |
Import email file while offline |
Email imported to client |
31 |
POP3 Offline Email Backup |
Backup cached emails |
Backup file created |
32 |
POP3 Offline Email Restore |
Restore emails from backup |
Emails restored successfully |
33 |
POP3 Offline Email Signature |
Add signature to offline-composed email |
Signature added correctly |
34 |
POP3 Offline Email Encryption |
Encrypt email while offline |
Email encrypted and queued |
35 |
POP3 Offline Email Decryption |
Decrypt cached encrypted email |
Email decrypted successfully |
36 |
POP3 Offline Email Compression |
Compress email attachments offline |
Compression successful |
37 |
POP3 Offline Email Sync Conflict |
Handle sync conflicts after reconnect |
Conflict resolved with user input |
38 |
POP3 Offline Email Sync Priority |
Prioritize sync queue after reconnect |
Priority respected |
39 |
POP3 Offline Email Sync Status |
Show sync status after reconnect |
Status displayed correctly |
40 |
POP3 Offline Email Sync Notification |
Notify user when sync completes |
Notification shown |
41 |
POP3 Offline Email Quota Check |
Check mailbox quota offline |
Quota unavailable or cached |
42 |
POP3 Offline Email Read Receipt |
Request read receipt offline |
Receipt sent after reconnect |
43 |
POP3 Offline Email Rules Execution |
Apply rules to offline emails |
Rules executed correctly |
44 |
POP3 Offline Email Tagging |
Tag emails offline |
Tags saved and synced |
45 |
POP3 Offline Email Archive |
Archive emails while offline |
Emails moved to archive |
46 |
POP3 Offline Email Restore from Archive |
Restore archived emails offline |
Emails restored successfully |
47 |
POP3 Offline Email Sync with Multiple Accounts |
Sync multiple accounts after reconnect |
All accounts synced |
48 |
POP3 Offline Email Sync with Large Mailbox |
Sync large mailbox after reconnect |
Sync completes without error |
49 |
POP3 Offline Email Sync with Limited Bandwidth |
Sync resumes with limited bandwidth |
Sync adapts to bandwidth |
50 |
POP3 Offline Email Sync with Proxy |
Sync resumes through proxy server |
Proxy used successfully |
Server Cleanup - Testcases
S.No |
Test Case |
Description |
Expected Result |
|---|---|---|---|
1 |
Delete After Download Enabled |
Enable delete after download |
Emails are removed from server after download |
2 |
Delete After Download Disabled |
Disable delete after download |
Emails remain on server after download |
3 |
Manual Delete via DELE |
Use DELE command to delete email |
Email is deleted from server |
4 |
QUIT After DELE |
Issue QUIT after DELE |
Email is permanently deleted |
5 |
No QUIT After DELE |
Issue DELE but not QUIT |
Email is not deleted (rollback) |
6 |
Delete Multiple Emails |
Delete multiple emails in one session |
All selected emails are deleted |
7 |
Delete Non-existent Email |
Try to delete an email that doesnt exist |
Error message returned |
8 |
Delete Already Deleted Email |
Try to delete an already deleted email |
Error or ignored |
9 |
Delete Large Email |
Delete email >10MB |
Email deleted successfully |
10 |
Delete Email with Attachment |
Delete email with files |
Email and attachments deleted |
11 |
Delete Email with Special Characters |
Email with special characters in subject |
Deleted without issues |
12 |
Delete Email with Unicode |
Email with Unicode content |
Deleted successfully |
13 |
Delete Email with HTML Content |
HTML email |
Deleted successfully |
14 |
Delete Email with Inline Images |
Email with embedded images |
Deleted successfully |
15 |
Delete Email with Long Subject |
Subject >255 characters |
Deleted successfully |
16 |
Delete Email with Long Body |
Body >1MB |
Deleted successfully |
17 |
Delete Email with Nested MIME |
Complex MIME structure |
Deleted successfully |
18 |
Delete Email with Corrupt Header |
Email with malformed header |
Deleted or error handled |
19 |
Delete Email with Corrupt Body |
Email with unreadable body |
Deleted or error handled |
20 |
Delete Email with Virus |
Email flagged as virus |
Deleted or quarantined |
21 |
Delete Email with Spam Flag |
Email marked as spam |
Deleted or moved to spam folder |
22 |
Delete Email from Specific Sender |
Filter by sender and delete |
Only matching emails deleted |
23 |
Delete Email by Date |
Delete emails older than X days |
Only old emails deleted |
24 |
Delete Email by Size |
Delete emails larger than X MB |
Only large emails deleted |
25 |
Delete Email by Subject Keyword |
Delete emails with specific keywords |
Matching emails deleted |
26 |
Delete Email by UIDL |
Use UIDL to delete specific email |
Correct email deleted |
27 |
Delete Email by Sequence Number |
Use message number to delete |
Correct email deleted |
28 |
Delete All Emails |
Bulk delete all emails |
Inbox is emptied |
29 |
Delete Emails in Batches |
Delete emails in groups |
Emails deleted in batches |
30 |
Delete Emails with Timeout |
Timeout during deletion |
Partial deletion or rollback |
31 |
Delete Emails with Network Drop |
Network fails mid-deletion |
Rollback or retry mechanism |
32 |
Delete Emails with Retry |
Retry deletion after failure |
Emails deleted on retry |
33 |
Delete Emails with Logging |
Enable logging |
Deletion actions logged |
34 |
Delete Emails with Audit Trail |
Track deletion history |
Audit trail maintained |
35 |
Delete Emails with Confirmation |
Prompt before deletion |
Confirmation required |
36 |
Delete Emails with Undo Option |
Allow undo after deletion |
Emails restored if undone |
37 |
Delete Emails with Delay |
Delay deletion by X minutes |
Emails deleted after delay |
38 |
Delete Emails with Quota Limit |
Mailbox near quota |
Deletion frees up space |
39 |
Delete Emails with Read Status |
Delete only read emails |
Unread emails retained |
40 |
Delete Emails with Flag |
Delete flagged emails |
Only flagged emails deleted |
41 |
Delete Emails with POP3 Script |
Use script to automate deletion |
Script executes correctly |
42 |
Delete Emails with POP3 Client |
Use email client (e.g., Outlook) |
Emails deleted as per settings |
43 |
Delete Emails with POP3 Proxy |
Use proxy server |
Deletion works via proxy |
44 |
Delete Emails with POP3 over SSL |
Secure connection |
Emails deleted securely |
45 |
Delete Emails with POP3 over IPv6 |
IPv6 connection |
Emails deleted successfully |
46 |
Delete Emails with POP3 Session Timeout |
Session expires mid-deletion |
Partial deletion or rollback |
47 |
Delete Emails with POP3 Server Restart |
Server restarts during deletion |
Deletion resumes or rolls back |
48 |
Delete Emails with POP3 Server Crash |
Server crashes mid-deletion |
Recovery mechanism triggered |
49 |
Delete Emails with POP3 Command Injection |
Attempt injection in DELE |
Input sanitized, no deletion |
50 |
Delete Emails with POP3 Access Control |
User lacks delete rights |
Deletion denied |
Limited Command Set - Testcases
S.No |
Test Case |
Description |
Expected Result |
|---|---|---|---|
1 |
USER Command Support |
Check if USER command is accepted |
USER command accepted |
2 |
PASS Command Support |
Check if PASS command is accepted |
PASS command accepted |
3 |
STAT Command Support |
Check if STAT command is supported |
STAT command returns message count and size |
4 |
LIST Command Support |
Check if LIST command is supported |
LIST returns message list |
5 |
RETR Command Support |
Check if RETR command is supported |
Message retrieved successfully |
6 |
DELE Command Support |
Check if DELE command is supported |
Message marked for deletion |
7 |
QUIT Command Support |
Check if QUIT command is supported |
Session ends gracefully |
8 |
NOOP Command Support |
Check if NOOP command is supported |
Server responds with +OK |
9 |
RSET Command Support |
Check if RSET command is supported |
Deletion marks cleared |
10 |
TOP Command Not Supported |
Attempt to use TOP command |
Server returns error |
11 |
UIDL Command Not Supported |
Attempt to use UIDL command |
Server returns error |
12 |
APOP Command Not Supported |
Attempt to use APOP command |
Server returns error |
13 |
CAPA Command Not Supported |
Attempt to use CAPA command |
Server returns error |
14 |
AUTH Command Not Supported |
Attempt to use AUTH command |
Server returns error |
15 |
PIPELINING Not Supported |
Attempt to send pipelined commands |
Server rejects pipelining |
16 |
TLS Upgrade Not Supported |
Attempt to start TLS session |
Server returns error |
17 |
Extended Commands Not Supported |
Attempt to use non-standard commands |
Server returns error |
18 |
Invalid Command Handling |
Send unknown command |
Server returns error |
19 |
Command Case Sensitivity |
Send commands in lowercase |
Server accepts or rejects based on config |
20 |
Command Order Enforcement |
Send commands in wrong order |
Server enforces correct sequence |
21 |
USER Without PASS |
Send USER without PASS |
Server waits for PASS |
22 |
PASS Without USER |
Send PASS without USER |
Server returns error |
23 |
RETR Without STAT |
Retrieve message without STAT |
Server allows or rejects |
24 |
DELE Without RETR |
Delete message without retrieving |
Message marked for deletion |
25 |
QUIT Without Login |
Send QUIT before authentication |
Session ends without error |
26 |
QUIT After DELE |
Send QUIT after marking messages for deletion |
Messages deleted |
27 |
QUIT After RSET |
Send QUIT after RSET |
Messages not deleted |
28 |
LIST Without STAT |
Send LIST without STAT |
Server responds with message list |
29 |
LIST With Message Number |
Send LIST with specific message number |
Server returns message size |
30 |
RETR With Invalid Message Number |
Retrieve non-existent message |
Server returns error |
31 |
DELE With Invalid Message Number |
Delete non-existent message |
Server returns error |
32 |
LIST With Invalid Message Number |
List non-existent message |
Server returns error |
33 |
RSET Without DELE |
Send RSET without any deletions |
Server responds with +OK |
34 |
NOOP Without Login |
Send NOOP before authentication |
Server returns error |
35 |
NOOP After Login |
Send NOOP after authentication |
Server responds with +OK |
36 |
RSET After RETR |
Retrieve and then reset |
Message not deleted |
37 |
DELE After RETR |
Retrieve and then delete |
Message marked for deletion |
38 |
Multiple RETR Commands |
Retrieve multiple messages sequentially |
All messages retrieved |
39 |
Multiple DELE Commands |
Delete multiple messages sequentially |
All messages marked for deletion |
40 |
RETR After DELE |
Retrieve a message after marking it for deletion |
Server returns error |
41 |
LIST After DELE |
List messages after marking some for deletion |
Deleted messages still listed |
42 |
STAT After DELE |
Check STAT after marking messages for deletion |
Count reflects undeleted messages |
43 |
STAT After RSET |
Check STAT after reset |
Count reflects all messages |
44 |
QUIT Without Any Commands |
Connect and immediately quit |
Session ends without error |
45 |
QUIT After Invalid Command |
Send invalid command then quit |
Session ends gracefully |
46 |
RETR Large Message |
Retrieve a large message |
Message retrieved successfully |
47 |
DELE Large Message |
Delete a large message |
Message marked for deletion |
48 |
LIST Large Mailbox |
List messages in a large mailbox |
List returned successfully |
49 |
STAT Large Mailbox |
Check STAT in a large mailbox |
Count and size returned correctly |
50 |
POP3 Limited Command Compliance Check |
Validate server against limited command set |
Server passes compliance test |
Authentication Support - Testcases
S.No |
Test Case |
Description |
Expected Result |
|---|---|---|---|
1 |
Valid Credentials |
Login with correct username and password |
Authentication successful |
2 |
Invalid Password |
Login with incorrect password |
Authentication failed |
3 |
Invalid Username |
Login with incorrect username |
Authentication failed |
4 |
Empty Credentials |
Attempt login with blank username and password |
Error message shown |
5 |
Case Sensitivity |
Use different case in username/password |
Authentication fails if case-sensitive |
6 |
Special Characters in Password |
Use special characters in password |
Authentication successful |
7 |
Long Password |
Use password >128 characters |
Authentication successful or error if limit exceeded |
8 |
Short Password |
Use password <6 characters |
Authentication successful or policy error |
9 |
POP3 APOP Support |
Use APOP authentication |
APOP handshake successful |
10 |
APOP with Invalid Digest |
Use incorrect APOP digest |
Authentication fails |
11 |
APOP with Expired Timestamp |
Use expired timestamp in APOP |
Authentication fails |
12 |
APOP Disabled |
Server with APOP disabled |
APOP not supported error |
13 |
USER/PASS Command |
Authenticate using USER and PASS commands |
Login successful |
14 |
USER Command Only |
Send only USER command |
Server waits for PASS |
15 |
PASS Command Only |
Send PASS without USER |
Error returned |
16 |
AUTH PLAIN |
Use AUTH PLAIN mechanism |
Authentication successful |
17 |
AUTH LOGIN |
Use AUTH LOGIN mechanism |
Authentication successful |
18 |
AUTH CRAM-MD5 |
Use CRAM-MD5 authentication |
Authentication successful |
19 |
AUTH Unsupported |
Use unsupported AUTH method |
Error returned |
20 |
AUTH with Invalid Base64 |
Send malformed base64 string |
Error returned |
21 |
AUTH with Empty Base64 |
Send empty base64 string |
Error returned |
22 |
AUTH with Expired Token |
Use expired token in AUTH |
Authentication fails |
23 |
AUTH with Reused Token |
Reuse token from previous session |
Authentication fails |
24 |
AUTH with Tampered Token |
Modify token before sending |
Authentication fails |
25 |
AUTH with SSL |
Authenticate over SSL |
Secure authentication successful |
26 |
AUTH with TLS |
Authenticate over STARTTLS |
Secure authentication successful |
27 |
AUTH without Encryption |
Authenticate over plain connection |
Warning or blocked |
28 |
Brute Force Attempt |
Multiple failed login attempts |
Account locked or throttled |
29 |
Rate Limiting |
Exceed login attempts per minute |
Rate limit enforced |
30 |
Session Timeout |
Idle session during authentication |
Session closed |
31 |
Concurrent Logins |
Multiple logins from same user |
Allowed or blocked based on policy |
32 |
Session Reuse |
Reuse session token after logout |
Authentication fails |
33 |
Logout After Auth |
Send QUIT after login |
Session ends gracefully |
34 |
Auth Logging |
Enable logging of auth attempts |
Logs generated correctly |
35 |
Auth Audit Trail |
Track login history |
Audit trail maintained |
36 |
Auth with Proxy |
Authenticate via proxy server |
Authentication successful |
37 |
Auth with VPN |
Authenticate over VPN |
Authentication successful |
38 |
Auth with IPv6 |
Authenticate using IPv6 |
Authentication successful |
39 |
Auth with DNS Resolution |
Use hostname instead of IP |
DNS resolves and login succeeds |
40 |
Auth with Invalid Hostname |
Use incorrect hostname |
Connection fails |
41 |
Auth with Server Down |
Server not responding |
Connection timeout |
42 |
Auth with Server Restart |
Server restarts during auth |
Session reset |
43 |
Auth with POP3S |
Use POP3 over SSL (port 995) |
Secure authentication successful |
44 |
Auth with POP3 (port 110) |
Use standard POP3 port |
Authentication successful |
45 |
Auth with Firewall Block |
Port blocked by firewall |
Connection refused |
46 |
Auth with Captive Portal |
Network redirects to login page |
Authentication fails |
47 |
Auth with Invalid Cert |
SSL cert invalid or expired |
Warning or blocked |
48 |
Auth with Self-signed Cert |
Use self-signed cert |
Warning shown or accepted |
49 |
Auth with Certificate Pinning |
Enforce cert pinning |
Auth fails if cert mismatch |
50 |
Auth with MFA (if supported) |
Use multi-factor authentication |
Auth successful after second factor |
Port Based Communication - Testcases
S.No |
Test Case |
Description |
Expected Result |
|---|---|---|---|
1 |
Default Port Connection (110) |
Connect to POP3 server using default port |
Connection established |
2 |
Secure Port Connection (995) |
Connect using POP3 over SSL/TLS |
Secure connection established |
3 |
Invalid Port Connection |
Attempt connection on an unused port |
Connection refused |
4 |
Port Blocked by Firewall |
Connect when port 110 is blocked |
Connection fails |
5 |
Port Open in Firewall |
Connect when port 110 is allowed |
Connection succeeds |
6 |
Port Scanning Detection |
Detect POP3 port via port scan |
Port detected |
7 |
Port Redirection |
Redirect POP3 traffic to another port |
Redirection successful |
8 |
Port-Based Load Balancing |
Distribute POP3 traffic across ports |
Load balanced correctly |
9 |
Port-Based Access Control |
Restrict access to POP3 based on port |
Access denied or allowed |
10 |
Port-Based Logging |
Log all POP3 traffic on specific port |
Logs generated |
11 |
Port-Based Rate Limiting |
Apply rate limits on POP3 port |
Limits enforced |
12 |
Port-Based QoS |
Prioritize POP3 traffic on specific port |
POP3 traffic prioritized |
13 |
Port-Based IDS/IPS Detection |
Detect anomalies on POP3 port |
Alerts triggered |
14 |
Port-Based VPN Tunneling |
Tunnel POP3 traffic through VPN |
Traffic encrypted and tunneled |
15 |
Port-Based Proxy Filtering |
Filter POP3 traffic via proxy |
Traffic filtered |
16 |
Port-Based NAT Traversal |
Access POP3 server behind NAT |
Connection successful |
17 |
Port-Based Connection Timeout |
Simulate timeout on POP3 port |
Timeout handled gracefully |
18 |
Port-Based Connection Retry |
Retry connection after port failure |
Retry successful |
19 |
Port-Based Connection Logging |
Log connection attempts by port |
Logs show port usage |
20 |
Port-Based Authentication Failure |
Fail authentication on POP3 port |
Error returned |
21 |
Port-Based Session Termination |
Terminate session on specific port |
Session closed |
22 |
Port-Based Encryption Enforcement |
Enforce SSL/TLS on port 995 |
Unencrypted connections rejected |
23 |
Port-Based Certificate Validation |
Validate SSL certificate on port 995 |
Certificate verified |
24 |
Port-Based DNS Resolution |
Resolve POP3 server via DNS |
IP resolved correctly |
25 |
Port-Based IP Filtering |
Allow/deny IPs on POP3 port |
Filtering enforced |
26 |
Port-Based Connection Throttling |
Throttle POP3 connections on port |
Throttling applied |
27 |
Port-Based Session Persistence |
Maintain session state on port |
Session persists |
28 |
Port-Based Connection Multiplexing |
Handle multiple sessions on same port |
Sessions managed correctly |
29 |
Port-Based Connection Isolation |
Isolate POP3 traffic from other services |
No cross-traffic interference |
30 |
Port-Based Connection Monitoring |
Monitor POP3 traffic on port |
Monitoring data available |
31 |
Port-Based Connection Encryption |
Encrypt POP3 traffic on port 995 |
Data encrypted |
32 |
Port-Based Connection Compression |
Compress POP3 traffic |
Compression applied |
33 |
Port-Based Connection Replay Protection |
Prevent replay attacks on POP3 port |
Replay blocked |
34 |
Port-Based Connection Spoofing Detection |
Detect spoofed POP3 traffic |
Spoofing detected |
35 |
Port-Based Connection Hijacking Detection |
Detect session hijacking attempts |
Hijacking blocked |
36 |
Port-Based Connection Flooding |
Simulate flooding on POP3 port |
Flood mitigated |
37 |
Port-Based Connection Logging Format |
Verify log format for POP3 port |
Logs formatted correctly |
38 |
Port-Based Connection Alerting |
Trigger alerts on suspicious POP3 activity |
Alerts generated |
39 |
Port-Based Connection Blacklisting |
Blacklist IPs on POP3 port |
Access denied |
40 |
Port-Based Connection Whitelisting |
Whitelist IPs on POP3 port |
Access allowed |
41 |
Port-Based Connection with IPv6 |
Connect to POP3 server using IPv6 |
Connection successful |
42 |
Port-Based Connection with IPv4 |
Connect to POP3 server using IPv4 |
Connection successful |
43 |
Port-Based Connection with Dual Stack |
Connect using dual-stack (IPv4 + IPv6) |
Both connections succeed |
44 |
Port-Based Connection with DNS Failover |
Failover to secondary DNS on port failure |
Failover successful |
45 |
Port-Based Connection with Load Testing |
Load test POP3 port |
Port handles load as expected |
46 |
Port-Based Connection with Packet Capture |
Capture POP3 traffic on port |
Packets captured successfully |
47 |
Port-Based Connection with Port Knocking |
Use port knocking to open POP3 port |
Port opened after knock sequence |
48 |
Port-Based Connection with Port Forwarding |
Forward POP3 port to internal server |
Forwarding successful |
49 |
Port-Based Connection with Port Mirroring |
Mirror POP3 traffic for analysis |
Traffic mirrored correctly |
50 |
Port-Based POP3 Compliance Check |
Validate POP3 behavior on all ports |
POP3 protocol compliance confirmed |
No Folder Support - Testcases
S.No |
Test Case |
Description |
Expected Result |
|---|---|---|---|
1 |
Single Mailbox Access |
Access mailbox via POP3 |
Only inbox is accessible |
2 |
Attempt to Access Folder |
Try accessing a folder (e.g., Sent, Drafts) |
Error or no response |
3 |
Folder Creation Attempt |
Try to create a folder via POP3 |
Operation not supported |
4 |
Folder Rename Attempt |
Try renaming a folder |
Operation not supported |
5 |
Folder Deletion Attempt |
Try deleting a folder |
Operation not supported |
6 |
Move Email to Folder |
Attempt to move email to another folder |
Operation not supported |
7 |
List Folders Command |
Try listing folders |
No folders returned or error |
8 |
IMAP Folder Syntax in POP3 |
Use IMAP-style folder path |
Invalid command or ignored |
9 |
POP3 Client with Folder UI |
Use client that supports folders |
Only inbox is synced |
10 |
Download from Non-Inbox |
Try to download from Sent or Spam |
Not possible via POP3 |
11 |
Server with Folder Support |
Connect to server with folders via POP3 |
Only inbox accessible |
12 |
POP3 vs IMAP Folder Comparison |
Compare folder access in both protocols |
POP3 shows inbox only |
13 |
Folder-Specific Filters |
Apply filters for specific folders |
Filters ignored or fail |
14 |
Folder-Specific Rules |
Apply rules to move emails to folders |
Rules not executed |
15 |
Folder Permissions |
Check folder-level permissions |
Not applicable in POP3 |
16 |
Folder Sync Attempt |
Try syncing folders |
Only inbox is synced |
17 |
Folder Metadata Access |
Try accessing folder metadata |
Not supported |
18 |
Folder Quota Check |
Check quota for specific folder |
Not supported |
19 |
Folder Subscription |
Try subscribing to a folder |
Not supported |
20 |
Folder Hierarchy Display |
Attempt to display folder tree |
Not supported |
21 |
Folder-Based Search |
Search emails in a specific folder |
Not supported |
22 |
Folder-Based Download |
Download emails from a folder |
Only inbox emails downloaded |
23 |
Folder-Based Deletion |
Delete emails from a folder |
Only inbox deletions allowed |
24 |
Folder-Based Archiving |
Archive emails to a folder |
Not supported |
25 |
Folder-Based Backup |
Backup specific folder |
Only inbox backed up |
26 |
Folder-Based Restore |
Restore to a specific folder |
Not supported |
27 |
Folder-Based Labeling |
Apply labels to folders |
Not supported |
28 |
Folder-Based Sorting |
Sort emails by folder |
Not applicable |
29 |
Folder-Based Rules Engine |
Apply rules per folder |
Not supported |
30 |
Folder-Based Notification |
Notify on folder updates |
Not supported |
31 |
Folder-Based Access Logs |
View logs per folder |
Not applicable |
32 |
Folder-Based Encryption |
Encrypt folder contents |
Not supported |
33 |
Folder-Based Retention Policy |
Apply retention per folder |
Not supported |
34 |
Folder-Based Spam Filtering |
Filter spam into folder |
Not supported in POP3 |
35 |
Folder-Based Virus Scanning |
Scan specific folders |
Not applicable |
36 |
Folder-Based Auto-Reply |
Auto-reply based on folder |
Not supported |
37 |
Folder-Based Forwarding |
Forward emails from a folder |
Not supported |
38 |
Folder-Based Tagging |
Tag emails in folders |
Not supported |
39 |
Folder-Based Access Control |
Set access per folder |
Not supported |
40 |
Folder-Based Audit Trail |
Track folder changes |
Not applicable |
41 |
Folder-Based Sync Conflict |
Conflict between folders |
Not applicable |
42 |
Folder-Based Email Count |
Count emails in folder |
Only inbox count available |
43 |
Folder-Based Email Size |
Total size of folder |
Only inbox size available |
44 |
Folder-Based Quarantine |
Quarantine folder access |
Not supported |
45 |
Folder-Based Retagging |
Retag emails in folders |
Not supported |
46 |
Folder-Based Migration |
Migrate folder contents |
Only inbox migrates |
47 |
Folder-Based Export |
Export folder contents |
Only inbox exported |
48 |
Folder-Based Import |
Import to specific folder |
Not supported |
49 |
Folder-Based Sync Logs |
Logs per folder sync |
Not applicable |
50 |
Folder-Based POP3 Extension |
Use POP3 extension for folders |
Not supported in standard POP3 |
Optional TLS Encryption - Testcases
S.No |
Test Case |
Description |
Expected Result |
|---|---|---|---|
1 |
Connect Without TLS |
Connect to POP3 server without using TLS |
Connection established in plain text |
2 |
Connect With TLS |
Connect to POP3 server using TLS |
Secure connection established |
3 |
STARTTLS Command Support |
Check if server supports STARTTLS |
Server responds with +OK |
4 |
STARTTLS Command Execution |
Execute STARTTLS command |
TLS handshake initiated |
5 |
STARTTLS Not Supported |
Attempt STARTTLS on server without support |
Server returns error |
6 |
TLS Negotiation Success |
Complete TLS handshake successfully |
Encrypted session established |
7 |
TLS Negotiation Failure |
Simulate TLS handshake failure |
Connection terminated |
8 |
TLS Certificate Validation |
Validate server certificate |
Certificate verified |
9 |
TLS Certificate Expired |
Connect with expired certificate |
Warning or rejection |
10 |
TLS Certificate Self-Signed |
Connect with self-signed certificate |
Warning or rejection |
11 |
TLS Certificate Revoked |
Connect with revoked certificate |
Connection rejected |
12 |
TLS Certificate Mismatch |
Hostname mismatch in certificate |
Warning or rejection |
13 |
TLS Version Compatibility |
Test with TLS 1.0, 1.1, 1.2, 1.3 |
Compatible versions accepted |
14 |
TLS Cipher Suite Negotiation |
Negotiate cipher suite during handshake |
Strong cipher selected |
15 |
TLS Session Resumption |
Resume previous TLS session |
Session resumed successfully |
16 |
TLS Downgrade Attack Prevention |
Prevent fallback to non-TLS |
Downgrade blocked |
17 |
TLS with STARTTLS then RETR |
Retrieve email after STARTTLS |
Message retrieved securely |
18 |
TLS with STARTTLS then DELE |
Delete email after STARTTLS |
Message deleted securely |
19 |
TLS with STARTTLS then QUIT |
Quit session after STARTTLS |
Session ends securely |
20 |
TLS with STARTTLS then STAT |
Check mailbox stats after STARTTLS |
Stats retrieved securely |
21 |
TLS with STARTTLS then LIST |
List messages after STARTTLS |
List retrieved securely |
22 |
TLS with STARTTLS then UIDL |
Use UIDL after STARTTLS |
UIDL executed securely |
23 |
TLS with STARTTLS then TOP |
Use TOP after STARTTLS |
TOP executed securely |
24 |
TLS with STARTTLS then RSET |
Use RSET after STARTTLS |
RSET executed securely |
25 |
TLS with STARTTLS then NOOP |
Use NOOP after STARTTLS |
NOOP executed securely |
26 |
TLS with STARTTLS then Invalid Command |
Send invalid command after STARTTLS |
Error handled securely |
27 |
TLS with STARTTLS then QUIT Without Commands |
Quit immediately after STARTTLS |
Session ends securely |
28 |
TLS with STARTTLS and Large Mailbox |
Access large mailbox over TLS |
All messages retrieved securely |
29 |
TLS with STARTTLS and Attachments |
Download attachments over TLS |
Attachments downloaded securely |
30 |
TLS with STARTTLS and Multiple Sessions |
Open multiple TLS sessions |
All sessions encrypted |
31 |
TLS with STARTTLS and Port 110 |
Use STARTTLS on port 110 |
TLS upgrade successful |
32 |
TLS with Implicit TLS on Port 995 |
Connect directly with TLS on port 995 |
Secure connection established |
33 |
TLS with STARTTLS and Port 995 |
Attempt STARTTLS on port 995 |
Server rejects or ignores |
34 |
TLS with STARTTLS and Proxy |
Use STARTTLS behind proxy |
TLS tunnel established |
35 |
TLS with STARTTLS and NAT |
Use STARTTLS behind NAT |
TLS works through NAT |
36 |
TLS with STARTTLS and VPN |
Use STARTTLS over VPN |
TLS works over VPN |
37 |
TLS with STARTTLS and IPv6 |
Use STARTTLS over IPv6 |
TLS works over IPv6 |
38 |
TLS with STARTTLS and IPv4 |
Use STARTTLS over IPv4 |
TLS works over IPv4 |
39 |
TLS with STARTTLS and DNS Failover |
Use STARTTLS after DNS failover |
TLS session re-established |
40 |
TLS with STARTTLS and Connection Timeout |
Simulate timeout during TLS handshake |
Connection fails gracefully |
41 |
TLS with STARTTLS and Packet Loss |
Simulate packet loss during TLS |
TLS retries or fails |
42 |
TLS with STARTTLS and High Latency |
Use STARTTLS in high-latency network |
TLS handshake completes |
43 |
TLS with STARTTLS and Email Forwarding |
Forward email after STARTTLS |
Forwarded securely |
44 |
TLS with STARTTLS and Email Deletion |
Delete email after STARTTLS |
Deleted securely |
45 |
TLS with STARTTLS and Email Search |
Search emails after STARTTLS |
Search results returned securely |
46 |
TLS with STARTTLS and Email Sync |
Sync mailbox after STARTTLS |
Sync completed securely |
47 |
TLS with STARTTLS and Email Backup |
Backup emails after STARTTLS |
Backup completed securely |
48 |
TLS with STARTTLS and Email Restore |
Restore emails after STARTTLS |
Restore completed securely |
49 |
TLS with STARTTLS and Logging |
Log TLS session activity |
Logs generated securely |
50 |
TLS Optional Mode Compliance Check |
Validate server behavior with optional TLS |
Server passes compliance test |
Reference links