Comment 27 for bug 314713

Experience similar problems on Ubuntu 9.04 x86-64 running Firefox 3.0.11 and Opera 9.62. Internet connection established via Draytek Vigor modem and 2910 router. Web sites affected include linkedin.com and google.co.uk/mail.

I've checked the same sites on my son's Vista PC and there's no problem whatsoever.

Running sudo ifconfig eth0 mtu 1360 did resolve the problem.