outgoing ssh fails from only one machine on lan to outside network

view full story

http://superuser.com – I have multiple servers in my LAN (which I'll refer to as Box1), and they are all able to make outgoing SSH connections, except one that stopped recently, which I'll refer to as Box2 (actually, I'm not 100% sure it ever worked, but I think I would have run into this before now if it didn't). They are all running Centos 6.3, with openssh on non-standard ports. Box2 is the entry point for the LAN from the outside world, and I am able to successfully ssh to it, so I know the port isn't blocked. Port forwarding works for either the non-standard port or 22, both forward to Box2. Box2 can ssh into B (HowTos)