As a system administrator, what Firefox plugin helps you do your job?

I know that there are several Firefox plugins that are invaluable for development. What plugins exist that are useful for system administration, monitoring, and the like? What plugins make your day-to-day job as a system or network administrator easier?

From serverfault Eddie

• Foxyproxy - I cant stand getting attacked by others when they walk over with their stats and say "Hm this Serverfault.com you wasted 5 minutes of our time on it."

  Portman : Wish I could upvote this more.

  Nick Kavadias : this looks more like a tool that would give sysadmins work to do! Maybe give it to all the end users as a ploy to get better funding for network security projects?
  From Shard

• Xmarks, cause who wants to maintain a local only copy of their Firefox bookmarks. Xmarks will sync your bookmarks across Firefox, IE etc on all your computers. It's fast and stays out of the way.

  Christopher Galpin : Now when will it sync my Chrome bookmarks? :(
  From Omar Shahine

• LastPass. So I don't have to remember the loads of accounts I use (and can generate very strong passwords for each of your accounts), both personal and at work.

  From Ivan

• ShowIP - allows me to see quickly the IP address of the server where a particular website is hosted. Assists in managing my many clients websites.

  DNSCache - quickly disable/re-enable Firefox's builtin DNS Cache, particularly good if your also manipulating the site's DNS at the time

  ScreenGrab - particularly good at capturing that error and sending to the developers.

  Milner : +1 for screengrab, makes life a lot easier!
  From Quog

• If you're using amazon ec2; elasticfox

  From xkcd150

• Even for IT, I'd have to put FireBug at the top of the list, too much good information in there.and

  From WaldenL

• Firebug and YSlow! FTW

  However I don't see why a web browser is a crucial tool for sysadmins, curl ? wget ? telnet host 80 ?

  Matt Simmons : I admin vmware server 2.x. If I don't run a website, I've got to use the 1500 character-long command lines.
  From Dave Cheney

• WebMail Notifier - Tracks web email accounts

  Live http headers - great for trouble shooting websites

  Ghostery watch the websites that watch you

  From UndertheFold

• ReloadEvery - so I can get SO refresh automagically while working!

  AdBlockPlus - because so many sites have ads that I don't care about.

  Mentioned before, but super +1 for Firebug and YSlow because there's typically some good information that can be gleaned depending on what issue you might get roped in to.

  From Milner

• Greasemonkey and the many scripts available for it is all I need.

  From David Collantes

• Tamper Data this is handy when you have to examine HTTP headers. This may be necessary if you have virtual hosts in a hosting environment. We also insert a field in the header to identify web machines in some of our web farms to identify problem hosts.

  From mryan1

• Charles Proxy with Firefox plugin is much better than Firebug network statistics.

  From Jake McGraw

• Delicious Bookmarks to sync my bookmarks across machines.

  spoulson : Yes! Yes! Yes! It's like a catch-all of all the useful content I've come across, tagged and sorted.
  From Adam Gibbins

• You can't work without something to give you rhythm

  From Dani
• • Live HTTP Headers
  • S3Fox
  From talonx

• Nagios Checker is pretty nice.

  From jwiz

• Fireftp for when you don't want to install an ftp client

  From Bourne

• In addition to others already mentioned, I find SQLite Manager invaluable.

  From John Gardeniers

• Update Scanner - For every site you have keep tabs on that doesn't have email notifications or rss.

  If you ar using google apps:

  Active Inbox - GTD for mail.

  From Erik