troubleshooting Question

Wireshark and Web Proxy settings

Avatar of neil4933
neil4933 asked on
NetworkingNetwork AnalysisTCP/IP
7 Comments1 Solution11089 ViewsLast Modified:
Hi

In our organisation, we have an HTTP proxy for web traffic: proxy.mycompany.com that operates on port 8080.

Without the proxy set in IE, I ran a Wireshark whilst attempting to browse to www.google.com - CAPTURE_A

I then set the proxy, and ran a Wireshark trace whilst attempting to browse to www.google.com - CAPTURE_B

Capture_A I can see:

i. Server queries DNS for proxy.mycompany.com
ii. All traffic related to www.google.com is then via the web proxy

For Capture_B

i. Server queries DNS for www.google.com
ii. Server then attempts to make a connection directly to www.google.com
iii. I can see three SYN packets to google., but no responses

Does this sound about right?

I had some questions:

i. When searching for any traffic related to www.google.com, is it possible to enter a display filter for any packets with the word "google" in the INFO section?

ii. It's a bit ardous to filter for DNS traffic first, grab the packet number, and then remove the filter so I can see all traffic around that time, is it not possible to try and see the conversation related to google ONLY?

iii. I used a display filter of HTTP, but this doesn't capture the SYN packets as they are TCP, how would i be able to do this?

I'm new to Wireshark so any comments would be welcome :)
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