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Help! VLAN tagged and untagged routing
eth0 Link encap:Ethernet HWaddr 00:01:2e:2b:12:6e inet addr:192.168.1.6 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::201:2eff:fe2b:126e/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:72695907 errors:0 dropped:0 overruns:0 frame:0 TX packets:152520 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:64299304 (64.2 MB) TX bytes:22220802 (22.2 MB) Interrupt:21 eth0.3999 Link encap:Ethernet HWaddr 00:01:2e:2b:12:6e inet addr:10.39.0.75 Bcast:10.39.3.255 Mask:255.255.252.0 inet6 addr: fe80::201:2eff:fe2b:126e/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:839421 errors:0 dropped:0 overruns:0 frame:0 TX packets:82 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:1131088026 (1.1 GB) TX bytes:5180 (5.1 KB)
Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.1.0 * 255.255.255.0 U 0 0 0 eth0 220.127.116.11 * 255.255.0.0 U 0 0 0 eth0.3999 18.104.22.168 * 240.0.0.0 U 0 0 0 eth0.3999
I can clearly see IGMP messages exchange and that source address for the given multicast address 22.214.171.124 (one of the IPTV channels) is 126.96.36.199.
Now here is the question. I always thought that routes are for the outbound traffic, so the kernel knows where to shift packets when it travels out of the box (packet generated by the application or packet received from another interface, but not meant for the current box). In VLAN it is a little bit different. I manually removed network
$ route del -net 188.8.131.52 netmask 255.255.0.0
$ route add -net 184.108.40.206 netmask 255.255.0.0 dev eth0.3999
All the help or some link resources on the issue would much be appreciated.
- Join Date
- Sep 2010
Yes, I think you're right. Vlan must have a TAG and if you remove the route some packets cannot be identified as VLAN.
I don't think it's the same thing for inbound traffic, because if they pass trough a router it should be able to route them to the right way... but I'm not sure.
- Join Date
- Jun 2004
- North Hollywood, CA
In networking parlance, usually tagging is allowing multiple vlans over a single interface.
And a route is a route. It is bidirectional. The way you are using the routes, per interface, sort of makes each interface a router, with specific addresses to deal with. So you are using your Linux system as a little router. Although this should not cause a problem, there are reasons for not doing it this way. Mostly, causing more overhead on each interface, which in turn will cause more CPU usage on the entire system.
I have a Linux box that is my server and my file storage. On my router, I redirect all protocols to the server. But I do have to put my server's local IP address into my Windows system's hosts file. Otherwise, it would route out to the internet and then back to get to the server. That's sound like what is happening to you. Since multicast IP addresses are predesignated, unless you specify them in your internal network, the route would try to go out to the internet to try to find them.