Point and Curse
We're in a hotel. The hotel offers complimentary wired ethernet, and exorbitantly expensive WiFi access. One ethernet port per room. Carina and I both want to check our email and write on our blogs. I seriously considered bringing my spare WRT54G on this trip, just in case something like this happened; but of course I didn't.
I know well enough how to enable ip masquerading on my GNU/Linux laptop, and it's trivial to twiddle my WiFi connection details:
$ sudo su -
echo 1 > /proc/sys/net/ipv4/ip_forward
iwconfig eth1 essid 'foobar' mode 'ad-hoc'
ipconfig eth1 10.13.13.1 netmask 255.255.255.0 up
iptables -t nat -A POSTROUTING -s 10.13.13.0/24 -o eth0 -j MASQUERADE
Trying to get Carina's laptop to connect to the ad-hoc network I created was another matter, though. Windows' helpful point-and-click interface completely obfuscates the settings I needed to change. I could not find a way to disable the "preferred networks" list in favor of the manual connection I was trying to construct. Nor could I effectively prevent her laptop from automatically connecting to the hotel's wireless network. What would have been a two minute operation in GNU/Linux took more than twenty minutes, and produced a handful of colorful oaths from me.
Thankfully, I finally figured it out, and we're both happily blogging.
Nor is their feeble restriction on outgoing TCP port 25 any match for my
ssh -L 2500:www.skippy.net:25 skippy.net!