No inbound packets observed

cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 
Announcements
Please sign in to see details of an important advisory in our Customer Advisories area.

No inbound packets observed

L4 Transporter

Hello,

 

Trying to troubleshoot an issue of aged-out traffic flow. It was SSH traffic originated from customer's LAN and destined to Internet address. Packet capture was configured on the firewall for troubleshooting but only outbound (but no inbound) packets were observed inside the PCAP files. Tried via WebGUI and CLI.

 

Could it be that the incoming packets were dropped before the capture process, or packets never reached the firewall?
How to confirm?

 

Thanks in Advance.

1 accepted solution

Accepted Solutions

don't do the pre-parse without checking the dataplane 'load' beforehand, this option will bypass any filter definition you have set

if there's a lot of traffic, everything will be captured and your capture will become unuseable

 

 

did you follow the instructions in the guide: Getting Started: Packet Capture

 

I usually add a set of filters for the reverse flow, just in case the returning packets get dropped for some reason (the filter/capture is session aware, but if for example the returning packets got malformed or the sequence number is somehow altered, the packets may get discarded)

 

so i'd go, for example

filter1 src 10.0.0.1 dst 4.2.2.2

filter2 src 4.2.2.2 dst <NAT ipaddress> 198.51.100.1

 

is the session also indicating 0 packets received (show session id <#>)?

Tom Piens
PANgurus - Strata specialist; config reviews, policy optimization

View solution in original post

2 REPLIES 2

L4 Transporter

Hi Farzana,

 

You can check the 'pre-parse' option to check for packets before they hit the recieve stage of the firewall, this is usually layer 2 packets that do not traverse the firewall so have no need to go to the recieve stage. Other than that it looks like you have answered your own question, no packets being recieved by the firewall.

 

hope this helps,

Ben

don't do the pre-parse without checking the dataplane 'load' beforehand, this option will bypass any filter definition you have set

if there's a lot of traffic, everything will be captured and your capture will become unuseable

 

 

did you follow the instructions in the guide: Getting Started: Packet Capture

 

I usually add a set of filters for the reverse flow, just in case the returning packets get dropped for some reason (the filter/capture is session aware, but if for example the returning packets got malformed or the sequence number is somehow altered, the packets may get discarded)

 

so i'd go, for example

filter1 src 10.0.0.1 dst 4.2.2.2

filter2 src 4.2.2.2 dst <NAT ipaddress> 198.51.100.1

 

is the session also indicating 0 packets received (show session id <#>)?

Tom Piens
PANgurus - Strata specialist; config reviews, policy optimization
  • 1 accepted solution
  • 2684 Views
  • 2 replies
  • 0 Likes
Like what you see?

Show your appreciation!

Click Like if a post is helpful to you or if you just want to show your support.

Click Accept as Solution to acknowledge that the answer to your question has been provided.

The button appears next to the replies on topics you’ve started. The member who gave the solution and all future visitors to this topic will appreciate it!

These simple actions take just seconds of your time, but go a long way in showing appreciation for community members and the LIVEcommunity as a whole!

The LIVEcommunity thanks you for your participation!