Comment 1 for bug 522452

On further inspection, it appears that Lucid is "phoning home" to "rookery.canonical.com" every time I log in.
It's failures were being reported in my firewall log.

iptables: IN= OUT=ppp0 SRC=X.X.X.X DST=91.189.90.132 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=53213 DF PROTO=TCP SPT=44608 DPT=80 WINDOW=5808 RES=0x00 SYN URGP=0

If you're happy to let the MOTD scripts phone home, the problem can be fixed by adding an iptables rule (or the equivalent ufw command):

iptables -A OUTPUT -d rookery.canonical.com --dport 80 -j ACCEPT

This can also be mitigated by a more aggressive timeout:

Edit
/usr/lib/python2.6/dist-packages/UpdateManager/Core/MetaRelease.py

Change the timeout parameter on line 247 to 2 seconds:

            uri=urllib2.urlopen(req, timeout=2)

Thanks,
Mark