This is our old Q&A Site. Please post any new questions and answers at

Hi all

I want to debug SIP registration issues with a VoIP client app on my smartphone. If I use this VoIP service via the Twinkle VoIP client on my Linux Mint notebook, it works just fine. So there must be something funny going on in the depths of SIP handshaking on my smartphone.

I have initially installed Wireshark 1.6.7 on the notebook; I could sniff the local SIP handshaking with success, seeing both directions of the handshake.

To debug SIP handshaking on my smartphone, I additionally installed aircrack-ng to sniff my WLAN. I am using airmon-ng as root, which gives me mon0 port on Wireshark. WLAN traffic is successfully decrypted by Wireshark.

I see now all SIP REGISTER messages from my smartphone to the Internet, but no SIP answers from the registrar server. If I check other IP traffic, it's the same story, I see all packets with origin 192.168.1.x, but not the other way round.

How come I can only sniff outbound, but no inbound IP traffic?

Many thanks in advance for your advice!

asked 01 Sep '15, 09:13

Yoyo's gravatar image

accept rate: 0%

Do you have any capture or display filters active in Wireshark?

(01 Sep '15, 10:07) Amato_C

No, all filters are deactivated. When I scanned the notebook's own WLAN port, the settings were the same like for the scan of the smartphone/AP WLAN traffic.

(01 Sep '15, 11:46) Yoyo
Be the first one to answer this question!
toggle preview

Follow this question

By Email:

Once you sign in you will be able to subscribe for any updates here



Answers and Comments

Markdown Basics

  • *italic* or _italic_
  • **bold** or __bold__
  • link:[text]( "title")
  • image?![alt text](/path/img.jpg "title")
  • numbered list: 1. Foo 2. Bar
  • to add a line break simply add two spaces to where you would like the new line to be.
  • basic HTML tags are also supported

Question tags:


question asked: 01 Sep '15, 09:13

question was seen: 929 times

last updated: 01 Sep '15, 11:46

p​o​w​e​r​e​d by O​S​Q​A