ยง2024-04-28


Apr 28 19:40:33 h2Jammy dovecot: imap-login: Disconnected: Connection closed (disconnected before auth was ready, waited 0 secs): user=<>, rip=114.33.29.69, lip=192.168.16.248, session=<6OrLmiYX2oByIR1F>
Apr 28 19:40:33 h2Jammy dovecot: imap-login: Disconnected: Connection closed (no auth attempts in 0 secs): user=<>, rip=114.33.29.69, lip=192.168.16.248, TLS handshaking: Connection closed, session=<JiLMmiYXyrZyIR1F>

err-->Connection closed (disconnected before auth was ready

ConnectYourMailAccount-02.png

Apr 28 20:05:31 h2Jammy postfix/anvil[36451]: statistics: max connection rate 3/60s for (smtp:114.33.29.69) at Apr 28 19:59:43
Apr 28 20:05:31 h2Jammy postfix/anvil[36451]: statistics: max connection count 1 for (smtp:114.33.29.69) at Apr 28 19:58:46
Apr 28 20:05:31 h2Jammy postfix/anvil[36451]: statistics: max cache size 1 at Apr 28 19:58:46
Apr 28 20:05:37 h2Jammy dovecot: imap-login: Login: user=<alexlai>, method=PLAIN, rip=114.33.29.69, lip=192.168.16.248, mpid=36542, session=<g6lq9CYXeKdyIR1F>
Apr 28 20:05:37 h2Jammy dovecot: imap(alexlai)<36542><g6lq9CYXeKdyIR1F>: Disconnected: Logged out in=26 out=535 deleted=0 expunged=0 trashed=0 hdr_count=0 hdr_bytes=0 body_count=0 body_bytes=0
Apr 28 20:05:37 h2Jammy postfix/smtpd[36520]: connect from 114-33-29-69.hinet-ip.hinet.net[114.33.29.69]
Apr 28 20:05:37 h2Jammy postfix/smtpd[36520]: warning: SASL authentication failure: unable to canonify user and get auxprops
Apr 28 20:05:37 h2Jammy postfix/smtpd[36520]: warning: 114-33-29-69.hinet-ip.hinet.net[114.33.29.69]: SASL DIGEST-MD5 authentication failed: authentication failure
Apr 28 20:05:37 h2Jammy postfix/smtpd[36520]: warning: 114-33-29-69.hinet-ip.hinet.net[114.33.29.69]: SASL CRAM-MD5 authentication failed: authentication failure
Apr 28 20:05:37 h2Jammy postfix/smtpd[36520]: disconnect from 114-33-29-69.hinet-ip.hinet.net[114.33.29.69] ehlo=1 auth=0/2 quit=1 commands=2/4

chatGPT

ChatGPT
It seems like there are a few things going on in these log messages. Let's break it down:

Max Connection Rate: The postfix/anvil service is reporting that there was a maximum connection rate of 3 connections per 60 seconds from the IP address 114.33.29.69 at 19:59:43 on April 28th.
Max Connection Count: Another report from postfix/anvil indicates that there was a maximum connection count of 1 from the same IP address (114.33.29.69) at 19:58:46 on April 28th.
Max Cache Size: There was a maximum cache size of 1 recorded at the same time as the maximum connection count.
Dovecot Login: A user named "alexlai" logged into the Dovecot IMAP service from the IP address 114.33.29.69 at 20:05:37 on April 28th.
Dovecot Disconnection: The same user, "alexlai," disconnected from the Dovecot service shortly after logging in.
Postfix SMTP Connection: A connection was made to the Postfix SMTP service from the IP address 114.33.29.69 at the same time as the Dovecot login.
SASL Authentication Failure: There were authentication failures during the SMTP connection attempt, specifically for SASL DIGEST-MD5 and SASL CRAM-MD5 authentication methods.
Postfix SMTP Disconnect: The SMTP connection was disconnected shortly after the authentication failures.
To solve this issue:

Investigate Authentication Failures: Look into why SASL authentication failed for both DIGEST-MD5 and CRAM-MD5 methods. Check your authentication configuration in Postfix to ensure it's correctly set up.
Monitor Connection Rates: Keep an eye on the connection rates from the IP address 114.33.29.69 to see if there's any suspicious activity. It's possible that someone is attempting to authenticate multiple times within a short period.
Review Dovecot Logs: Check if there are any unusual activities related to the "alexlai" user in the Dovecot logs. Ensure that their login and logout actions are legitimate.
Consider Blocking IP: If the authentication failures and connection rates persist, consider blocking the IP address 114.33.29.69 temporarily to prevent further unauthorized access attempts.
Update Security Measures: Review and update your server's security measures, including password policies, firewall rules, and any other relevant configurations to enhance overall security.
Remember to keep monitoring the logs for any further suspicious activities and take appropriate actions as necessary.

User
how to disable SASL authentication in postfix main.cf
ChatGPT
To disable SASL authentication in Postfix, you need to adjust the configuration settings in the main.cf file. Here's how you can do it:

Open the main.cf file: Use your preferred text editor to open the main.cf file. Typically, this file is located in /etc/postfix/main.cf.
Find the SASL configuration: Look for any lines that begin with smtpd_sasl_auth_enable or smtpd_sasl_security_options. These lines control SASL authentication.
Disable SASL: Comment out or remove the lines related to SASL authentication. Here's an example of what the lines might look like:
shell
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#smtpd_sasl_auth_enable = yes
#smtpd_sasl_security_options = noanonymous
By commenting out these lines, you're effectively disabling SASL authentication.
Restart Postfix: After making the changes, restart the Postfix service to apply the new configuration. You can do this using the following command:
swift
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sudo systemctl restart postfix
Verify: Test your Postfix configuration to ensure that SASL authentication is disabled. You can do this by attempting to send an email through your Postfix server without providing any authentication credentials. If the email is sent successfully, SASL authentication has been disabled.
Remember to always back up your main.cf file before making changes, especially if you're not familiar with the configuration. This allows you to revert to the previous configuration if something goes wrong.