08-14-2017 05:51 AM - edited 03-12-2019 02:49 AM
Hello Experts,
Can you guys please explain me..what is the best way to put the packet capture command on Cisco ASA.
1.When the traffic is going from inside to outside (which interface would be the best to capture the traffic)..?
2.When the traffic is going coming from outside to inside(which interface would be the best to capture the traffic)..?
The only reason I'm getting confused is because we do have NAT configuration on ASA sometimes and this makes me scratch my head.
I would really appreciate if you guys can please explain me this.
Thanks
Sam
08-14-2017 07:01 AM
Hi Sam,
When traffic is outbound that is from inside:
packet-tracer input inside
When traffic is inbound :
packet-tracer input outside
packet-tracer input outside
So in the destination, you would typically use a NAT IP rather than the real IP.
Regards,
Aditya
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08-14-2017 09:07 AM
Hi Aditya,
Thank you for replying...
Actually I'm looking for packet capture command for e.g.
capture cap-in match tcp host 1.1.1.1 host 2.2.2.2 eq 80
Thanks
Sam
08-14-2017 09:20 AM
Hi Sam,
My bad :)
If you need the packet capture for outbound traffic and inbound traffic you need to capture in both the directions:
Ingress capture:
capture
This match statement is bi-directional.
In case there is NAT then you need to make a slight change.
Let's say you have a dynamic NAT for internet access for inside users and traffic is not working:
Something like this:
object-network obj-10.0.0.0
subnet 10.0.0.0 255.255.255.0
nat (inside,outside) dynamic 1.1.1.1
capture cap interface inside match
capture capo interface outside match
This would capture the traffic on both the interfaces and you would know in which direction the traffic is working or not.
Regards,
Aditya
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08-14-2017 10:08 AM
Hi Aditya,
Thank you for replying.. really appreciate your effort
can you please give me some good links to documents which would help me in understanding these things.
Thanks again
Thanks
Sam
08-14-2017 09:17 PM
Hi Sam,
Here are some links:
https://www.cisco.com/c/en/us/support/docs/security/asa-5500-x-series-next-generation-firewalls/118097-configure-asa-00.html
https://www.tunnelsup.com/packet-captures-on-cisco-asa/
Regards,
Aditya
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