IPSec from iOS - connection ok, but XMPP traffic stops flowing after awhile

[pax]

Greetings,

We have a pfSense firewall setup that is accepting connections from iOS devices (and soon Android).  It seems connections are established and traffic flows correctly.  However, after some period of time XMPP traffic stops flowing.  SSH traffic still works, so it is only XMPP.

I don't see anything in the logs to indicate what could be going wrong, but restarting the IPSec service cures the symptom, so it seems to be more within IPSec than a firewall issue.

I haven't noticed any specific timing - could happen in a day, could be two weeks.

Any pointers or suggestions on what to look at would be greatly appreciated.