I have postfix running on Ubuntu 12.04 and mails are sent without issues but from past few days have issues only while sending mail to gmail mail servers Code: telnet gmail-smtp-in.l.google.com 25 Trying 18.104.22.168.. Connected to gmail-smtp-in.l.google.com. Escape character is '^]'. It just hangs there and connection closed by foreign host. But do not have any issues sending to yahoo, hotmail etc IP address is not listed in any of the blacklists. Pls help.