Disable XF86Back/Forward

Real ThinkPad keyboards (not this monstruous ignominy) have directly accessible keys for XF86Back and XF86Forward. That is really problematic with web browsers such as Firefox or Chromium since pressing those keys transparently go back or forward into your history, discarding anything you were typing in the process, including that 3 hours long bug report you were just about to submit. That’s rather annoying, to say the least.

Some other blog post suggest to simply disable them with xmodmap. That is in ~/.xmodmaprc (or whatever it is you use):

keycode 166 = NoSymbol
keycode 167 = NoSymbol

I personally prefer to remap them to Next/Prior keys. Having these near the navigation keys might come up handy:

keycode 166 = Next
keycode 167 = Prior

That’s on Linux though, on FreeBSD the keycodes are 233 and 234:

keycode 233 = Next
keycode 234 = Prior

Anyway use the xev command and xmodmap -pke to find the keycodes and remap them to any other interesting key symbol.

Conntrack table flood

Recently we had problems with our gateway, connections were dropped and so on.
After a bit of investigation we found that it was due to a bugged game using Javascript which, when it ran on Firefox, opened connections in a loop flooding the connection tracking table in a matter of hours. Once found, it was easy to fix. This was also the occasion to tighten the timeouts values of nf_conntrack a little bit. Indeed 5 days timeouts for established connection doesn’t really make sense when your public IPv4 change every 36hours or so.