Wireshark-users: Re: [Wireshark-users] Wireshark, Ubuntu, and mystery UDP packets
Hi all!
FWIW: 232.0.0.0/8 is the Source-Specific Multicast block.
http://www.iana.org/assignments/multicast-addresses/multicast-addresses.xhtml
Whatever system is meant to receive that stream can - within reason - be expected to support IGMPv3; else it might not be able to subscribe to that stream properly. Might helpo with the research on the surrounding systems in your network.
Other thing that springs to mind:
Both Virtualbox and Wireshark capture start set the NIC to promiscuous mode, don't they? That's something that might be in common between VBox and capture.
Depending on the network infrastructure you are connected to, the packets you capture might not even be your own. If you have access to the LAN switchport counters, be sure to check if the sustained 6Mpbs stream is in- or outbound from the switch port, and if it comes and goes with VBbox or capture being active or not, or if it is permanent.
Double-Check: Does the source MAC in the received frames match your NIC's address?
best regards
Marc
----Ursprüngliche Nachricht----
Von : stephanecharette@xxxxxxxxx
Datum : 2016.06.04 - 03:51 (WEDT)
An : wireshark-users@xxxxxxxxxxxxx
Betreff : [Wireshark-users] Wireshark, Ubuntu, and mystery UDP packets
When I start Wireshark, all is fine. But when I start capturing, this creates a steady stream of UDP packets. As soon as I stop the capture, the stream stops. I've never noticed this before.
The UDP stream is one directional, going to multicast address 232.9.3.115, port 6288. Each packet is 1328 or 1332 bytes of binary payload. The packets are sent at a steady rate of 5.3Mbps. The following options are
disabled in wireshark:
- resolve mac address
- resolve network names
- resolve transport names
- promiscuous mode
This is my normal local desktop, running 16.04, kernel 4.4.0.22-generic. Local, not a remote desktop. Wireshark is installed from the normal Ubuntu repo:
> dpkg -l | egrep "wireshark|pcap" | grep -v "rc "
ii libpcap0.8:amd64 1.7.4-2 amd64 system interface for user-level packet capture
ii libwireshark-data 2.0.2+ga16e22e-1 all network packet dissection library -- data files
ii libwireshark6:amd64 2.0.2+ga16e22e-1 amd64 network packet dissection library -- shared library
ii wireshark 2.0.2+ga16e22e-1 amd64 network traffic analyzer - meta-package
ii wireshark-common 2.0.2+ga16e22e-1 amd64 network traffic analyzer - common files
ii wireshark-qt 2.0.2+ga16e22e-1 amd64 network traffic analyzer - Qt version
I'm at a complete loss as to why starting a packet capture on my local desktop is causing this mystery stream of UDP packets. I'm hoping someone can tell me either why, how to stop this, or can confirm the same strange behaviour.
Stéphane
