issue with IPF firewall state tables

Murray Taylor MTaylor at bytecraft.com.au
Mon Nov 7 04:53:05 UTC 2011


Back Story:

Old Server (X32 system, probably FreeBSD 4.3-ish) 
New Server (Dual core, X64 with plenty of RAM) running 8.1-RELEASE

New Server was put in production last night as a core router, with 
the same rc.conf, firewall rule set and config from the old router 
that has been working for years.

At around 12 Lunchtime we had reports of no internet connectivity, 
I've jumped onto the router and seen that it is blocking a whole 
heap of internal to external DNS server traffic, along with other 
would-be allowed traffic.

I promptly flushed the firewall ruleset with "ipf -Fa", and noted 
that the rules did clear - Issue still existing.
I re-loaded the rule set, no change.
Upon restart, the router began to behave itself again...

I have been using "ipfstat -ts | grep active" to get a count of 
state entries, and comparing to the 4013 default.

We are sitting on around ~2000 state entries. I am aware I can 
flush the state table, but until the router breaks itself again, 
I cannot clear it.

Does this sound like a full state table? Am I using the best 
method to check? Is there any form of notification that this 
is happening anywhere?


-- 
Murray Taylor
Bytecraft Systems
Special Projects Engineer

P: +61 3 8710 0600
D: +61 3 9238 5168
F: +61 3 9238 5140

 |_|0|_|        "Absence of evidence
 |_|_|0|        is not evidence of absence"
 |0|0|0|        Carl Sagan



 
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