postfix doesn't work with IP as hostname

Using Ubuntu 14.04 x64

I had a working installation of Postfix which was handy for sending emails in my terminal, but I had an issue with an application that was critical for my workflow. In order for it to function correctly and I had to change my local machine's hostname to my network IP.

hostname `hostname -I`

https://superuser.com/a/571073/175088

Doing this fixed my work-critical application, but now postfix isn't working. I purged and re-installed postfix to pick up the new hostname, but attempting to start the postfix service now errors with the following message:

postfix: warning: valid_hostname: numeric hostname: [IP-Redacted]
postfix: fatal: file /etc/postfix/main.cf: parameter myhostname: bad parameter value: [IP-Redacted]

Is it possible to get postfix to work with an IP address as my hostname?

Paul Nelson Baker

Posted 2014-07-18T20:51:42.660

Reputation: 155

Why do you want to set it to an IP? There is no requirement that your hostname has to match myhostname of postfix. Set it to some FQDN – clement – 2014-07-20T10:53:16.113

Really? It was still set to my original hostname, but it stopped working after I made the fix for my work program. That's when I purged and re-installed postifx. As far as just setting it to an FQDN. I don't actually have a hostname that is associated with my address on our internal DNS. Before it was just set to whatever Ubuntu put it as during installation. – Paul Nelson Baker – 2014-07-21T00:29:55.827

I'm trying to debug this with telnet and postfix says 501 5.1.3 Bad recipient address syntax when I put an IP address where you'd normally put the host name. – Alex W – 2015-08-11T19:22:05.130

postfix doesn't work with IP as hostname

Answers