I've got a new modem/gateway/router/switch/AP and configured it. So the temporary modem from my girlfriend can go back to her place.
The device possibilities are quite extended, although I think the configuration (at least the web configuration) doesn't offer all possibilities I'd like, but nothing I can't live with.
And this time I did check if my server was reachable from the internet... 
Of course, it would have been a good idea to test whether my server was reachable from the internet (which it wasn't)... I forgot to configure the NAT section of the modem, which means no NAT at all...
Stupid me!
But now, finally, my server is reachable again.
I've borrowed a modem from my girlfriend, as she doesn't need it now herself, because her ADSL line still isn't working since she moved. This will of course only be temporary, but she'll probably lend it even when her ADSL line starts working, but I hope my internet provider will be willing to supply a new modem to me and that it will happen soon.
Then my internet connection will of course go offline for a while when connecting and configuring that new modem, but hopefully it won't take much time (as it will be supplied by my internet provider and will be pre-configured by them to working values).
But finally, I've got a life again, after being (almost entirely) disconnected for a few days...
My modem seems to be having trouble right now. I don't know in advance how long it will take for me to correct the situation, but it will probably take a while.
Some parts of my web site have been configured to use the HTTPS protocol, with 256-bit encryption by a certificate you can get for free at
http://www.startssl.com/, a Certificate Authority which is recognized by about any browser, except Internet Exploder and Opera. However, unfortunately they now use a Class 1 Intermediate Server CA for these certificates, and this Intermediate CA isn't installed (yet) in these browsers (and you have to get the Root CA for Internet Exploder and Opera also anyway, because they don't recognize StartSSL at all)...
To install this Intermediate CA, go here for the CRT file and here for the PEM file. For Internet Exploder and Opera, first click here to retrieve the Root CA (and if that doesn't work, click here to retrieve the PEM file instead), then get the Intermediate CA on the left. Then all your troubles will go away and you can live happily ever after.
Had a disaster with my server a few weeks ago. My hard disk broke down. Now it is running the very latest of Mandriva, with a RAID-1 configuration so that it is still there when a hard disk fails. Frequent backups are made to a third hard disk.
It took some time to get it running to my liking again, because I didn't have backups of everything (like /etc configuration) or very old data (like /var/lib/mysql, so my SQL databases) from an old Ghost image I made in 2005.
But it's new, and it's spiffy now!