On Fri, Mar 29, 2013 at 12:37 PM, Pat Haley <phaley at mit.edu> wrote: > > Hi, > > Actually we're talking about both SSH and XDMCP X11 forwarding. > Both seem to be currently disabled by the iptables. > > We'll try out what you suggest and get back with the results. > Thanks. > > Pat iptables should have no effect (well. I guess if you do some really odd config settings it -could-, but that's a bit of an edge case) on ssh X tunnels. check your /etc/ssh/sshd_config for X11Forwarding it should be set to yes. if you have iptables that apply to localhost/127.0.0.0/8 network, then I suppose iptables could be part of the problem. but I'd think it'd make sense to drop most all of those rules. it might also be helpful to look at the output of from your external machine when you run ssh -vvvv -X user at clusterhost (I wouldn't send it all to the list, cuz it'll be a ton of nonsense, but the last page or of output lines have helped me find issues in the past) ... or am I completely off in left field and you're saying you're unable to ssh into your machines? -- Even the Magic 8 ball has an opinion on email clients: Outlook not so good.