The SMTP (send mail) server for the Tsukuba University CS department can only be accessed from whith the university. With the fair amount of travelling I do while working (or even when working from home), I need some way to log in and send my e-mails whenever necessary.

One “simple” way to do that is an SSH tunnel with a localhost port redirect. I tell my mail reader (thunderbird) to read a certain port in localhost instead of the normal mail port, and in this port I connect to my laboratory machine, which connects with the university mail server.

Although this setup is quite simple, one problem with it is that it requires me to switch the configurations of thunderbird around — either to the normal e-mail server, or to the local port redirect.

Another solution, whose setup would be a little more complicated, but should be simpler to use once it was working, is to use a “Virtual Private Network” (VPN). The VPN creates a “virtual” network, so that when you connect to it, your computer behaves transparently as if it were inside the server’s network. So even if was in Paris, all my trafic would be routed through my VPN server, inside the university.

I set it up some weeks ago, and it worked perfectly on the public network inside the university (which, since not being in the CS department, can’t be used for sending e-mails). However, I messed up with something in the configuration, because I can’t get the VPN to work in any other network. I tried to fix it today, but I just get some weird messages about the packets to the VPN host being filtered when I ping it…

Well, I’m so freaking busy at this moment that I will have to push fixing the VPN server into my growing pile of tasks for now…

UPDATE (29/12/2012)I just confirmed that the VPN works in at least two different networks inside the university (but outside the CS department). So this is definitely some sort of firewall issue. Which is a bit weird, since all the VPN communication is supposed to happen through SSH, which is not blocked by the university firewall…