I am using centos 7 with postfix with smtp. The mail server was working fine, but then it stopped working. I cannot telnet to Gmail or any other server on port 25,587,465. However, when I telnet myowndomain.com 25
< it works.
It seems as if I cannot telnet to port 25 or any port of other servers. The error is given below.
Jun 16 05:24:06 SSSS postfix/submission/smtpd[25687]: connect from unknown[172.17.0.2] Jun 16 05:24:06 SSSS postfix/submission/smtpd[25687]: Anonymous TLS connection established from unknown[172.17.0.2]: TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)
Jun 16 05:24:06 SSSS postfix/submission/smtpd[25687]: 0F69747687: client=unknown[172.17.0.2]
Jun 16 05:24:06 SSSS postfix/cleanup[25690]: 0F69747687: message-id=<[email protected]>
Jun 16 05:24:06 SSSS postfix/qmgr[24527]: 0F69747687: from=, size=6806, nrcpt=1 (queue active)
Jun 16 05:24:06 SSSS postfix/submission/smtpd[25687]: disconnect from unknown[172.17.0.2] Jun 16 05:24:12 SSSS postfix/smtpd[25473]: connect from unknown[89.248.171.223]
Jun 16 05:24:12 SSSS postfix/smtpd[25473]: warning: unknown[89.248.171.223]: SASL LOGIN authentication failed: authentication failure
Jun 16 05:24:12 SSSS postfix/smtpd[25473]: disconnect from unknown[89.248.171.223]
Jun 16 05:24:36 SSSS postfix/smtp[25691]: connect to smtp1.linuxfoundation.org[140.211.169.13]:25: Connection timed out
Jun 16 05:24:55 SSSS postfix/smtpd[25473]: connect from unknown[155.133.64.146] Jun 16 05:24:55 SSSS postfix/smtpd[25473]: warning: unknown[155.133.64.146]: SASL LOGIN authentication failed: authentication failure Jun 16 05:24:55 SSSS postfix/smtpd[25473]: disconnect from unknown[155.133.64.146]
MAIN.CF:
inet_protocols = ipv4
inet_interfaces = all
smtpd_recipient_restrictions = permit_sasl_authenticated ,permit_mynetworks , reject_invalid_hostname, reject_unauth_destination,check_helo_access hash:/etc/postfix/helo_access, reject_non_fqdn_recipient, reject_rbl_client zen.spamhaus.org, reject_rbl_client bl.spamcop.net
smtpd_relay_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination
telnet connection:
[root@mail ~]# telnet alt4.gmail-smtp-in.l.google.com 25
Trying 74.125.28.27...
telnet: connect to address 74.125.28.27: Connection timed out
Trying 2607:f8b0:400e:c04::1a...
telnet: connect to address 2607:f8b0:400e:c04::1a: Network is unreachable
any solution? I have already tried many tutorials from online, but didn't help.