topic Re: Turning Off DNS Lookups When Performing Dataplane Packet Capture? in General Topics

Turning Off DNS Lookups When Performing Dataplane Packet Capture?

ClarkeMorledge — Tue, 20 Aug 2019 20:17:30 GMT

Is it possible to turn off DNS lookups when performing packet captures on the dataplane?

I was hoping to run some pcaps, without taking up too many unnecessary resources through DNS lookups.

Thanks.

Re: Turning Off DNS Lookups When Performing Dataplane Packet Capture?

reaper — Wed, 21 Aug 2019 09:56:36 GMT

you can narrow down your packet-diag filters so you only capture what you're trying to troubleshoot (I'd recommend it, over disabling functionality because your filter is too generic)

Re: Turning Off DNS Lookups When Performing Dataplane Packet Capture?

ClarkeMorledge — Wed, 21 Aug 2019 15:03:30 GMT

That's true. I can do that.

But the other issue I have is that I would really like to see the IP addresses, in the default output, at times, and not the DNS name.

Is it even possible to turn off the DNS lookups?

Clarke Morledge

William & Mary

Re: Turning Off DNS Lookups When Performing Dataplane Packet Capture?

OtakarKlier — Wed, 21 Aug 2019 15:51:23 GMT

Hello,

The PCAPs will have the IPs listed. As for disabling, I'm not sure and dont recommend it.

Regards,

Re: Turning Off DNS Lookups When Performing Dataplane Packet Capture?

ClarkeMorledge — Wed, 21 Aug 2019 19:59:35 GMT

I should have clarified what I was asking for.

The quick and easy pcap viewing command that I found was this:

view-pcap filter-pcap name_of_file.pcap

When running this command, the default is to give you the DNS lookups. Otherwise, I am not sure how to just look at the source/destination IP addresses, without offloading the pcap. So, I was curious to know if there was some mechanism to view the pcap, like this, without having to show the DNS lookup information.

Thanks.

Re: Turning Off DNS Lookups When Performing Dataplane Packet Capture?

S.Cantwell — Wed, 21 Aug 2019 20:52:08 GMT

Good Afternoon

It is quite simple to do a packet capture trace from CLI and exclude DNS, if I understand your question.

view-pcap follow yes no-dns-lookup yes

I believe you are looking for the no-dns-lookup option.

this is be done by CLI only, not from the GUI.

Does this help?

Re: Turning Off DNS Lookups When Performing Dataplane Packet Capture?

ClarkeMorledge — Wed, 21 Aug 2019 21:15:48 GMT

Thanks, Steve. We have a winner. I appreciate your help.