08-18-2008 06:57 AM - edited 03-11-2019 06:32 AM
I use a 2821 IOSFW for internet access
It holds 14 DMZ (one Vlan / server on each)
and about 2000 internal internet daily users.
My internet access is 10Mbps symetric.
When trafic grows, CPU grows correspondingly to IP trafic, up to 50%.
I suppose that CPU load is due to IP nat, ACLs and CBAC between inside and outside.
Some external Citrix users sometimes loose their connexion.
Cisco's Commercial argue that I should migrate to ASA 5510, but I need some features like PBR which is unavailable.
I am looking for a serious diagnostic method.
08-18-2008 09:16 AM
Try checking the CPU load during low volume and high volume times.
show proc cpu | e 0.00% 0.00% 0.00%
I don't think you'll get a definitive answer but it should help point in the right direction.
Also check this-
http://www.cisco.com/en/US/docs/ios/12_0t/12_0t4/feature/guide/fw800.html#wp20431
CBAC was designed for SMBs, not really Enterprises. I understand that routers work better (and I usually suggest them to my customers), but you might have to figure out new routing techniques and put in a ASA firewall.
Hope that helps.
08-19-2008 07:19 AM
08-26-2008 07:29 AM
Thanks for reply, but for now due to budget restrictions, I must face the problem without investments.
CPU is mainly due to outbound http traffic.
1) I moved Http PBR from 2821 to inside C3750E vlan switch.
I hope I will gain 10-20% of CPU.
2) Http outbound trafic goes to a squid proxy machine.
If I connect Squid's second Eth Int to another Internet IosFW router (using a free public IP address), may be I can reduce CPU overload of 2821.
I guess Http inspect CBAC is the most CPU consumer.
do you know if there is a better IOSFW release which runs CBAC in hardware as ASAs Asic does ?
For now, I run IosFW 12.4.16 standard train.
Best regards
08-18-2008 11:22 AM
Downgrade the router from an Advanced Sec license to lower and get an ASA :)
You are pushing the router to its limits it seems. Have you looked at the optimization for CBAC?
http://www.cisco.com/en/US/docs/ios/12_2t/12_2t8/feature/guide/ftfirewl.html
Regards
Farrukh
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