Tue, 21 Feb 2006
Sat, 28 Jan 2006
Parasitic Traceroute and Other Hidden Gems
Dan Kaminskys Paketto Keiretsu is a collection of small networking tools that contain some great ideas. This week I needed to work out where an encrypted tunnel was actually going, not where the untrusted OS said it was going, and paratrace was a great little app to have in my toolkit.
While none of the tools are essential (or going to be needed that often) they do fill a pretty lonely niche.
Tue, 11 Oct 2005
Windows Ethernet Bonding
I spent a while today trying to get my head around Ethernet bonding, under Windows 2000 Server, on an IBM machine. Firstly a tangent, IBM has a great site with a lot of good content. And a bloody rubbish search engine and no overview on how anything fits together. I know organising that much data must take a lot of clue but hey, this is IBM! One of the few places that still actually does research.
I'll take a moment to explain what Ethernet bonding is. Most servers have two or more network interfaces in them. If you assign them both different IP's then when one goes down the other isn't much use. If you assign them both the same IP then you get conflicts. Don't do that.
If you care about availability (or performance) you can make the two of them work together to give you added redundancy (or throughput) by making them both listen to a given address. If one stops working then the other carries on functioning and service isn't interrupted. If you're smart you'll put each interface on different switches to remove another single point of failure.
Back to my point, I'm posting this in the hope that the next poor Linux sod who needs to do this sees this post and saves themselves a lot of faffing around. Firstly most Windows people, and vendors, call Ethernet bonding Network Teaming. You'll get more results if you search for that term. Secondly, and this may be an IBM using Intel pro card thing but even after you've installed the software the settings tabs WILL NOT BE VISIBLE WHEN LOGGED IN USING TERMINAL SERVICES. I assume this is to stop you shooting yourself in the foot. Just think of: "What happens if I make this TEAM invalid? Oh. Call me a cab to the colo..."
Lastly if you get errors about multiple gateways when you try and assign the IP address to the "TEAM" interface then you should give up and cry. Sorry, you need to get both nics set up on the same range before trying again. If you don't run DHCP just make them both "Assign by DHCP" and when they have addresses in the 169 range configure the "TEAM" interface with the desired IP.
The odd thing about all this was the enjoyment of pulling a cable out at the end and saying "Look! It still pings!" and being given that "That's a good boy. Put the weapon down now" look.