Comment 2 for bug 1461340

Please note I had to upgrade to the 1.5.2 series in order to get a working system on Ubuntu 15.04.
I have packaged this and put an upgraded package in my PPA: ppa:rhardy/webconsrp
The new package works for me. I went for a fresh config file on the new version but that is optional.
The package is based on the original package for vivid but was upgraded to handle the new release.

I have never figured out how to actually get that "published" so it shows in Universe. If the original maintainer knows how feel free to either take the packages or the patches there in which I had to port so they applied to the 1.5.2 series. There were also packaging changes to handle the new css and templates directories which are new in 1.5.2. The package still recommends squirrelmail-viewashtml but will actually remove that when it is installed. The squirrelmail 1.5.2 seems to have that built in now. I'll find where that recommend is coming from at some later point...

Please note you must have a working certificate verification chain for the package to work. To get this I had to ensure /etc/ssl/certs had the full certificate chain and then ran a c_rehash in that directory.

Ultimately openssl must be able to cleanly connect for the rest to work. I found this helpful for debugging:
openssl s_client -CApath /etc/ssl/certs -connect <FQDN>:<PORT>

If you have it configured properly you should see "Verify return code: 0 (ok)" near the end of the output, if not add certificates and c_rehash until you do.

To make the php and squirrelmail use that working certificate validation chain I did two things:
 1. I configured openssl.capath in /etc/php5/apache2/php.ini
 2. I created a /etc/squirrelmail/config_local.php. See config_local.example.php for hints. I used capath instead of cafile.

You may be able to get away with only one of those but I did both and it works for me.