Email server: lost connection while receiving initial server greeting (gmail only)

gmailpostfixsmtp

Past few days users are unable to send mail to gmail, by checking the logs I found the following error message "lost connection with gmail-smtp-in.l.google.com while receiving initial server greeting"
But there are no issues while sending mail to yahoo, hotmail etc.
->Tried by disabling firewall-no success
->Tried to send by directly connecting without router-no success
->Tried telnet

telnet gmail-smtp-in.l.google.com 25
Trying 74.125.141.26..<br/>
Connected to gmail-smtp-in.l.google.com.
Escape character is '^]'.

It just hangs there without sending the 220 greeting

I am narrowing it to ISP network issue, since I am able to telnet to same gmail server from another ISP network

what else could be causing this issue ?

Best Answer

The fact that you were able to establish a connection to the gmail smtp server implies port 25 is not blocked by your ISP. This seems to me, I could be wrong, either a delayed greeting from gmail to deter spam or your IP has been blacklisted. Either way it is the mail server which is preventing your from proceeding to the next level. Try it from a different public IP.

When tests fail before the 220 SMTP server greeting