Apache fails to start when listening on specific IP

[angusm]

I have an Apache 2.2.8 install running on a Fedora Core 7 box. The server runs fine, and has been serving multiple name-based virtual hosts without problems for several months.

The 'httpd.conf' file contains a single Listen instruction, of the form:

Listen 80

My server currently has three IPs configured on the NIC, and because the configuration doesn't specify an IP, it listens on all of them. I'd like to restrict Apache to using just one.

However, if I change that instruction to

Listen x.x.x.x:80

(where 'x.x.x.x' stands for the actual IP of my server), Apache fails to start up, reporting:

(98)Address already in use: make_sock: could not bind to address x.x.x.x:80
no listening sockets available, shutting down

Restoring the original Listen instruction allows it to work again.

Shutting down Apache and using netstat to look for anything listening on port 80 doesn't reveal any competitors for port 80. Watching the 'messages' log during Apache startup doesn't show any signs to suggest that selinux is interfering.

Can anyone suggest why this might be occurring, and recommend a fix? Thanks.

[daverj]

try using lsof (must be root) to see if there are any offenders:

lsof -iTCP:80

the above will return any files opened by a process running on port 80. lsof has many other options, but this should show you if port 80 is being used by another process.

davidj

[angusm]

Hmm. That disclosed that something yum-related had seemingly stalled and was apparently holding open some connections to remote sites (probably long since dead). I killed the parent process, bounced Apache and everything is fine.

Someone out there probably understands why stale connections to external sites will stop Apache binding on a single IP, but not on three, but I'm sure I don't.

Thanks for the suggestion.