I'm also having this same issue. However, mine will stay connected for < 30 seconds. Tho it seems it depends on the amount of data. Its about long enough for me to ssh into a host and su to root, and then it stops responding, and this error is in /var/log/syslog
Mar 18 19:43:28 carnage vpnc[11612]: connection terminated by dead peer detection Uname: Linux carnage 2.6.20-12-generic #2 SMP Sun Mar 18 03:07:14 UTC 2007 i686 GNU/Linux Date: Sun Mar 18 19:45:57 MDT 2007 -- vpnc dead peer detection disconnects immediately https://launchpad.net/bugs/93413 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs