Clearing a Cisco Router's Dynamic NAT Table

I keep needing to do this – so once again to help my future self:

When you have a number of public IPs being translated through a router to an internal address space, a router’s dynamic translation can get full. I’ve got an 877W, and it seems that a combination of running BitTorrent and a CounterStrike: Source server can quickly cripple the router (even with a memory upgrade!). When it gets too full you end up getting timeouts on other connections, usually this is most obvious by my browser failing to return pages.

To clear the dynamic translation table before timeout occurs log in to the router via ssh (or telnet) and in enable mode, type:

clear ip nat translation *

That seems to do the trick on my network anyway.

VHD Size

Again, a techy post more for my future self’s benefit (so little space in my memory for anything useful, it being full of StarTrek trivia and the like). A trick to optimise a VHD (Microsoft’s Virtual Harddrive format – used in Virtual PC and Virtual Server). Turn of the system file checker. Not always advisable, but if you’ve created a machine where you think you don’t need it, try this.
To turn off SFC, open a command prompt and run

sfc /cachesize=0
sfc /purgecache

Then perform the standard compaction routine in Virtual PC/Virtual Server. For even more benefit, see also the Invirtus Optimizer which is outstanding, taking a 4.2GB VHD down to 1.4 by removing the cruft it didn’t need.