I've been trying to follow these instructions, so that I could get the Citadel mail server to work alongside Apache, but I get an error when I try to restart Apache:
Invalid command 'ProxyPass', ...
I was told in the Apache docs that this is from the mod_proxy module, but
apt-get install mod_proxy gives
E: Couldn't find package mod_proxy, and I was unable to find it on the big list on the Apache site. What do I need to do to get the ProxyPass working in Ubuntu 10.04 TLS?