Multicast Router with Gentoo?

Gatak · Apprentice Joined: 04 Jan 2004 Posts: 174

Hello,

My ISP is broadcasting TV programs BBC and Discovery over their network with multicast. I'd like to be able to view these TV programs from my LAN clients.

The problem is now on how to make my Gentoo Linux router to work with multicast, and let my clients subscribe to the different channels and receive the multicast data.

I currently have a working linux router with NAT, etc, which I manage with iptables.

I can ping 224.0.0.1 from my LAN clients and my Gentoo box (192.168.0.1) will respond.

My LAN is like this:
LAN[192.168.0.x] <--> [192.168.0.1]-Gentoo-[83.227.154.117] <--> [83.227.154.65]-ISPs router

I get every few seconds a IGMPv2 "Membership Query" from my ISP. They also respond to ping 224.0.0.1 from my Gentoo box.

How should I setup with iptables, mrouted, or something similar to allow my LAN clients to receive the multicast data from the internet?

egberts · Posted: Tue Jul 12, 2005 11:42 am Post subject: emerge mrouted

What you've describe is a end-host multicasting functionality of joining/leaving a multicast group.

To do forwarding, what you appear to need is a multicasting router.

Check out 'emerge mrouted'
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Gatak · Apprentice Joined: 04 Jan 2004 Posts: 174

Yes, many seem to recommend mrouted. I have tried this program and have yet to get it to work. When running it in debug mode I see my LAN client wanting to join a group. Then I do not see anything more happening really other than membership querries etc. No data is being forwarded nor received from my ISP.

However, if I try to join the multicat group from my router itself, then I am receiving real data from my ISP. I have been unable to forward anything to my LAN clients, with and without mrouted. Has anyone actually used mrouted?

This is the info my ISP gave me regarding the multicc ast channels. If I use VLC - Video LAN Client - to receive the channel on the router itself it works sort of. It would receive video data but be unable to actually decode it. If I try the same from the LAN client nothing would be received.

egberts

Sadly to say, mrouted works best if each and EVERY router in the hop is running an equivalent of an mrouted.

I know many brain-dead ISP don't bother with multicast. Sometime you can do a mtrace (traceroute equivalence of a multicast).

The tool is located at [url]sourceforge.net/projects/mtrace/[/url] (GENTOO should have this, but its not in the portage) to determine which multicast hop is broken.

Then, sadly again, lodging a complaint with the midhop backbone provider MAY or MAY NOT result in a suitable resolution.

For me, I always establish a multicast island of which I can join together using GRE tunneling protocol (not the best of both world).

Best wishes.
_________________
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Gatak · Apprentice Joined: 04 Jan 2004 Posts: 174

Well. The multicast from my ISP does work. I do receive multicast querries over IGMP when I monitor with Ethereal. I can join the right multicast group with Video LAN Client on the Router.

The problem is to get mrouted, or something similar, to allow my LAN clients to join the multicast group and receive the traffic. As far as I have seen they cannot even join the group so the ISP starts sending me the video data. =(

Is there a way for me to debug or anything? I have run mrouted in the console with debug output but I am not sure exactly what to look for.

adaptr · Posted: Wed Jul 13, 2005 10:10 am Post subject:

You do understand that you need to be able to route the multicast packets through your NAT, yes ?

There may be one or more sysctl or kernel options you need to set or tweak.
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Gatak · Apprentice Joined: 04 Jan 2004 Posts: 174

Gatak · Apprentice Joined: 04 Jan 2004 Posts: 174

The problem as I see it is that the router does not proxy the multicast packets.

When I join a group from my LAN, the router would not join the group with the next router. So therefore I would not get any response. Here is some debug output.

Before joining a group from the LAN:
mrouted.cache

agit8or · n00b Joined: 24 Jul 2004 Posts: 3 Location: Sweden

Hi,

I managed to route multicast traffic from my ISP through my firewall/gateway using static routes and the smcroute daemon (don't know if this is in portage)

I assume your ISP is Bredbandsbolaget, right? They multicast these three channels in their net. Anyway, this is the way I once got it to work

Gatak · Apprentice Joined: 04 Jan 2004 Posts: 174

agit8or · n00b Joined: 24 Jul 2004 Posts: 3 Location: Sweden

Gatak · Apprentice Joined: 04 Jan 2004 Posts: 174

thepustule · Posted: Thu May 04, 2006 4:52 am Post subject:

I've been trying the same thing here with mrouted.

I have a Linux firewall router with 3 interfaces. One for the internet, one for wired lan, and the other for a "Wireless DMZ" where my access point sits.

I want to be able to multicast TV using VLC from a LAN client and pick it up on a wireless client.

Same trouble - no matter what I do, linux won't forward the packets.

Is there no one out there doing multicast?