Solved: Embryonic Connection Limits and Embryonic Connection Timeouts in FWSM

yuchenglai · ‎08-19-2008

I noticed in the FWSM's configuration guide that the number of embryonic connection limits can be configured using using static nat translations. I also noticed that the timeouts for embryonic connections can be configured using Modular Policy Framework. Without explicitly configuring a limit to the number of embryonic connections (through static nat statements), does the FWSM have a threshold for the number of embryonic connections that it will allow before taking action? Is it safe to assume that embryonic connections will timeout in 20 seconds if no modular policy framework policy was explicitly configured to set the embryonic connection timeout limit in the FWSM?

Syed Iftekhar Ahmed · ‎08-19-2008

If no MPF policy is in place then the default embryonic connection timeout is 20 sec. (It was 5 sec in pre 2.2 code).

you cannot set the maximum embryonic connections using the set connection (MPF command), you can only set the embryonic connection timeout using this command.

You can only set embryonic connection limits using NAT.

Syed

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Syed Iftekhar Ahmed · ‎08-19-2008

If no MPF policy is in place then the default embryonic connection timeout is 20 sec. (It was 5 sec in pre 2.2 code).

you cannot set the maximum embryonic connections using the set connection (MPF command), you can only set the embryonic connection timeout using this command.

You can only set embryonic connection limits using NAT.

Syed

yuchenglai · ‎08-20-2008

Were there reasons why the default embryonic connection timeout was bumped from 5 seconds to 20 seconds?

Syed Iftekhar Ahmed · ‎08-20-2008

5 second is not a very long time for half open connections (specially if you cant change it).

Remember in old FSWM codes this embryonic connection timeout was hardcoded and was not configurable.

Syed