Error in mail Notification in postfix

[vimalparikh]

Team,

Suddenly mail stop working in Nagios, Getting bellow error . Please help me out.

-Queue ID- --Size-- ----Arrival Time---- -Sender/Recipient-------
EC33F2A2A5 759 Fri Dec 22 10:31:34 nagios@localhost.localdomain
(host mail.zydushospitals.com[202.131.96.164] said: 450 4.7.1 Client host rejected: cannot find your reverse hostname, [10.11.200.254] (in reply to RCPT TO command))
ahmitinfra@zydushospitals.com
vimalparikh@zydushospitals.com


request you to help me out

[dwhitfield]

This is possibly a DNS issue, but can you post your /etc/postfix/main.cf? Also, considering we will be out of the office on Monday and Tuesday, and that this does not seem like a nagios issue, I would suggest checking out a postfix forum or perhaps https://serverfault.com/

If you want to continue here, that's great, and there may be community feedback on Christmas and Boxing Day, but don't anticipate any techs to be able to jump in until Wednesday next week.

[vimalparikh]

team,

Please find the main.cf file output and guide for the same.

[cdienger]

This would appear to be a DNS issue - mail.zydushospitals.com is unable to find the hostname for 10.11.200.254. Do you have access to the mail.zydushospitals.com server? Does the command "nslookup 10.11.200.254" on the mail.zydushospitals.com return the hostname of the nagios server ?