What could cause issues with multicast function on a modem

[Halden_1]

So I have had many internet issues, as in total outages, that the system blames on dns errors, and then I have the isp remotely diagnose the modem and they find no issue, at least yet, and I have tried everything imaginable to diagnose the routers, install new lan card drivers, and so forth.

These are intermittent and then I get maybe a week of problem free internet. But I finally found an article that at least seemed relateable to the issues I was having, so I just wanna throw some possible ideas out on the table.

http://www.dslreports.com/forum/r7373685-Connection-Flooded-by-multicast

This is an article about a guy with a charter modem who seemed to have his connection completely mess up from being flooded by multicast packets, which ultimately made him unable to use a router, only able to directly connect to the modem. (which I cannot do because of type of modem, presumably)

It sounded similar to my situation so I thought I'd share it.

When looking at my connections again I noticed many many connections to public dns addresses, many icmp connections, all sorts of different ones, but again, that may be normal traffic. However the multicast connection, the main one for multi ip broadcasting on the local subnet was very high on the traffic list it, which stood out. I tried to filter it out in QoS settings, by setting the byes to 0 on its address and port, but I still saw it sending bytes so I have no idea if that did anything or worked, I need a better understanding of my router's settings or another third party application to correctly filter it, which was what people told this guy to do in the lnked thread, in order to prevent the flooding.

The TLDR was that maybe charter's modem was having compatibility issues with his routers or his server or computer to the extent that it caused the glitch, I mean it's way over my head tho so. I'm not sure.

This came up. Not sure what the packet rate should be.

"IPV4 UNKNOWN 0.0.0.0:0 all-systems.mcast.net:0 83.09 KB (2659 Pkts."

Here's an excerpt of his situation

"to stan999
Ok, here we go:

July 5th, literally while using the internet, connection fails. List of attempts to fix:
*success indicates internet connection, DHCP working, ping success, and ability to enter router's setup.
*failure indicates no internet connection, no DHCP, Ping time out, and inability to connect to router's setup screen.

-power down router and reset: failure to fix.
-power down modem and router and reset: failure.
-connect to modem with WinXP client and reset: success.
-pull Linksys BEFSX41 and replace with Netgear NWR04B Wireless router: Success for ~5 min, then failure.
-Go on vacation for 1 week, pull power on all units and plug in when I return: success ~hours, then failure.
-Replace router with Siemens Speedstream SS2604 (uses 192.168.254.254): Success ~5-6 days, then failure.
-Replace Siemens with Win2000 Adv Server: Success ~hours, then failure. Here, the server was still able to connect to the internet through it's WAN interface, however was unable to DHCP, ping, connect in any way to clients on the LAN side. In server's Routing and Remote Access service, of the 4 network interfaces listed (WAN, Local, Loopback, and some other???) all show ok except for the Local netork interface which shows "disconnected".
-Pull server and connect WinXP client directly to BEFSX41 WITHOUT the router's WAN port connected to the modem: Able to connect to router, ping, DHCP. All shows ok.
-Connect BEFSX41 to modem: Success ~4-5 minutes, then failure.
-Attempted to clone MAC address: Failure.
-Attempted to filter Multicast packets: failure.
-Reinstalled TCP/IP stack: Failure
-Reinstalled NIC: Failure
-Installed new NIC: Failure
-Attempted simple ICS: Failure
-1 hour on phone with Linksys trying all kinds of wacky stuff: failure.
-RMA router to Linksys and try with new unit: Initial success, then failure.

Even in failure, all the link lights show good connection (WAN, Switch ports to clients, etc.)

There's more I'm sure, but I've been troubleshooting for about 6 weeks without any prolonged success. NOTE: I'm always able to reconnect with immediate success with one client connected straight to the modem, but the introduction of a router blows the whole thing."

 

[stdragon]

0.0.0.0 is the route of last resort. AKA your default gateway.

Do did you have anything else attached to this router when you connected it to the modem? Perhaps some DLNA Media services or TV?

 

[Halden_1]

0.0.0.0 is the route of last resort. AKA your default gateway.

Do did you have anything else attached to this router when you connected it to the modem? Perhaps some DLNA Media services or TV?

It has an amazon fire hd thing that connects via wifi, as well as a directtv box, both of which I've suspected of causing interference. Also interestingly when i did an avast network diagnostic it lists the all systems mcast thing as though it were a lan interface or a device itself or something wierd like i thought a neighbor was stealing wifi or something it seemed surprising, and i only now realize what the mcast thing is, after reading up and posting the op.

 

[bill001g]

Multicast is not really used on the internet....it is very surprising since it was designed for video streaming but nobody uses it.

On your lan really the only multicast packets you will see are start with 224.0.0.x. Not sure what the router is complaining about 0.0.0.0 likely is a normal broadcast. Still that is likely measured over a long period of time.

I suspect you getting off the track looking at muliticast. Mutlicast will never cross the LAN/wan so you can not filter it. Consumer routers can not filter lan-lan traffic. You can easily see if there is a lot of multicast traffic with a simple wire shark capture. Since consumer routers do not really support multicast it is treated at broadcast. You should see any traffic on any machine.

Maybe its time to spend $50 and get a midrange 802.11ac 1200 rated router. When I looked up the routers you have been using they are extremely old devices, I at first though maybe this was a old thread someone reposted.

Still since you have tried multiple routers it almost has to be the modem. Most cable modems have a log that show events. You will always see some junk but if it drops you should get a message.

 

[stdragon]

Start out by only connecting one PC to the router, and the router WAN to the modem. Disable WiFi if you must. But be sure nothing on your internal subnet is the cause first.

 

[Halden_1]

I've noticed some tale tale signs that maybe point to the routers. Neither are very good admittedly, but I really need to leave the better one on to test more.

Anyways when I download files they seem to download at a normal speed initially than stall up about half way through and lag really hard, at least during times when the internet starts to show signs of wanting to go out by acting slower or buggier. And certain video streaming sites although not youtube download slowly after initially going fast, things like vimeo and steem lnks, or higher video quality streams.

I also use a lot of financial sites like trading view and exchanges, which seem to also make the internet angry because of the load. It's kind of like a clogged pipe I guess. But the linksys router i have is ancient, and the other one is a travel router.

 

[failboat]

Take devices off your network and see if the lag goes away.

Try and deduce the issue.

You might have malware trying to spread over the LAN.

It might be for network discovery. The packets wouldn't add up to a lot of data. Are you running a windows share?
I think those use discovery. I have to type in the address to connect to my shares on turnkey file server.