Here is dmesg file. Nothing gets written to syslog on this issue. I think I might be mistaken on xubuntu 6.10 having the exact same issue. Most of the time tonight I was able to close Firefox without losing connectivity but can easily reproduce the problem if Firefox crashes or I kill the process. xubuntu 6.06 I had the problem every time Firefox closed.
** Attachment added: "dmesg" http://librarian.launchpad.net/6767983/dmesg -- lose network connectivity after closing firefox https://launchpad.net/bugs/90886 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs