Jdub points out a couple of packages which I’m off to install right now.
I’ve always redirected to a “one true” FQDN on my websites by using an extra virtualhost container and a redirect rule. libapache2-redirtoservname to the rescue!
I don’t use as much PHP as a I used to but I’m sure that what little is on there will find php5-xcache gives it a boost.