route entries after ICMP redirect

[Sergey Matveychuk]

I've got some problem with route entries that was created after ICMP 
redirect messages. They are never expired.

Our default gateway (it's a HP switch) send ICMP redirect messages if it 
see a short path to destination. It's makes it not so overloaded. But 
pathes sometime changed. There is no problem with Windows workstations, 
they are rebooted daily. But my FreeBSD boxes hold dinamic route entries 
forever.

I've looked through RFCs and Stevens' books and found no answer on what 
TTL for this entries.
Now I just add route flush as cron job. But may be there is another way?

-- 
Sem.