SMTP Problem "cannot find your hostname"

[floh79]

Hello,

I noticed many logs about rejecting emails from atlassian. Here a snipplet from my server-log:

May 30 09:37:34 mail postfix/postscreen[32640]: CONNECT from [136.147.141.72]:47641 to [10.10.10.3]:25
May 30 09:37:34 mail postfix/postscreen[32640]: PASS OLD [136.147.141.72]:47641
May 30 09:37:34 mail postfix/smtpd[32576]: warning: hostname mta2.e.atlassian.com does not resolve to address 136.147.141.72
May 30 09:37:34 mail postfix/smtpd[32576]: connect from unknown[136.147.141.72]
May 30 09:37:35 mail postfix/smtpd[32576]: NOQUEUE: reject: RCPT from unknown[136.147.141.72]: 450 4.7.25 Client host rejected: cannot find your hostname, [136.147.141.72]; from=<bounce-1441644_HTML-1523370683-104672418-524000040-38@bounce.e.atlassian.com> to=<*********> proto=ESMTP helo=<mta.e.atlassian.com>
May 30 09:37:35 mail postfix/smtpd[32576]: disconnect from unknown[136.147.141.72] ehlo=2 starttls=1 mail=1 rcpt=0/1 quit=1 commands=5/6 

So there is some problem with resolving hostname for mta2.e.atlassian.com. Whats wrong?

Best regards
Floh

[Nic Brough -Adaptavist- · Accepted solution]

Your computer is unable to find that address.  I'd sugest that there is something wrong with your DNS setup somewhere (possibly a cache needs flushing somewhere?)

[floh79]

Thank you for your reply.

I found out that DNS-Request was blocked by Firewall because the configuration of firewall was accidentally overwritten. Now it's fixed and it works.

Best regards
Floh