Apache 404 error Log to a different log file

Question

We want to separate 404 not found errors into a different log file. Now our log file (apache) that writes this errors is in "access.log" file.

We want to have 404 not found errors for example in notfound.log

I did a test writting in apache2.conf:

LogFormat "%{X-Forwarded-For}i %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" notfound

and in VirtualHost of apache sites-available:

CustomLog ${APACHE_LOG_DIR}/not-found.log notfound expr=.*404.*

But I got "error in condition clause"

I tried to set a env variable in VirtualHost too:

SetEnvIf expr .*404.* httpcode

And call it in CustomLog expr but didn't work. Somebody can help us, please?

Thank you.

Answer 1

Your approach could work if you install the custom Apache module SetEnvIfPlus. This should allow you to set an environment variable using the ResponseSetEnvIfPlus directive and then use that envirionment variable to force a custom log file.