It appears upgrading from Apache 2.2 to 2.4 changed the format of the errorlog file. Error logs used to show the remote client IP address.

Apache 2.2 errorlog: [Thu Aug 29 08:28:46 2019] [error] [client] message

Apache 2.4 errorlog: [Thu Aug 29 08:02:23.779174 2019] [:error] [pid 10036] message

Benevolently, Apache 2.4 added the ErrorLogFormat directive. So I specified:

 ErrorLogFormat "[%{u}t] [%-m:%l] [%a] %M"

But the %a format string that is supposed to show "Client IP address and port of the request" is giving me blank.

Now the errorlog: [Thu Aug 29 11:13:13.281770 2019] [-:error] message

What I expected: [Thu Aug 29 11:13:13.281770 2019] [-:error] [] message

The format string Client IP addresses are correctly showing up in the accesslog, which has a %h format string for "Remote hostname". There is no such format string for ErrorLogFormat.

We're running a dedicated Rackspace CentOS 7.6.1810 running, Apache 2.4.6.

1 Answer 1


%a started working when we updated mod_wsgi from 3.4.18 to 4.6.2. Thanks to Fedor V. at WSM International.

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