OT - IGMP Protocol query

[Thermodyne]

Where did you get this info from? Firewall?

Looks like the system is asking a router for info on other systems in its group. Is the system in the workgroup named "workgroup"?

[Baron Grazic]

This is a new Test XP machine, that I built to test a new Internal Firewall on our Domain. This Fireall is blocking the IGMP packets and brought it to my attention.
At least a couple of times a day, the XP machine sends packets to the address of 224.0.0.22, which routes to igmp.mcast.net
We are not using any Multicasting software, and this XP box is pure Windows XP, no other software except for the Virus/Firewall client that I am testing.
Suggestions?

[Instar]

http://www.webopedia.com/TERM/I/IGMP.html
Not exactly a wordy definition.
I can't find what mcast.net is. I haven't been able to ping it or anything. Whois comes up blank. I can't say what that is or what it is doing. What brand of A/V stuff are you using? Firewall?

[Baron Grazic]

Thanks Instar.
I am testing TrendMicro OfficeScan Anti-Virus software and Firewall.
There is a couple of references to igmp.mcast.net but not why XP would be attempting to connect to it, once a day.

[Instar]

I used to use Trend Micro. It was good enough.
Anyhow, its a weird thing, trying to contact a non-existant site (unless its an evil government plot! The ILLUMINATTI are coming!)
Its a multicast IP protocol... hmm
No harm in continuing blocking it. I know IE has a toolbar thing that Adaware considers spyware. Get Adaware on disk and see what happens when you run it.

[Thermodyne]

It’s an unassigned IGMP address. I would just block it at the firewall. It’s probably just a multicast from your system (host) looking for members.

Here’s a link to IGMP

http://www.freesoft.org/CIE/RFC/1112/18.htm


As a rule of thumb, you should build a list of what the firewall needs to pass and then lock everything else down. In practice, we lock it all down and then open as needed. Often, we apply filters to the PIX’s on a per machine basis. Allowing all internally originating traffic is no longer seen as acceptable.

PS: TM's antivirus has had some bigtime patch blowups in the past.

[Instar]

"PS: TM's antivirus has had some bigtime patch blowups in the past. "
I didn't notice that when I used it, then again, I had a fast connection to download the patches with, and I had a huge HD anyhow.

[minipol]

As a rule of thumb, you should build a list of what the firewall needs to pass and then lock everything else down. In practice, we lock it all down and then open as needed.

That's the only correct way to do it IMHO. Lock it down, watch the logs and look what bounced, then open if you know what service is responsible for the hit.