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dE_logics Advocate
Joined: 02 Jan 2009 Posts: 2253 Location: $TERM
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Posted: Sat Oct 12, 2013 3:56 am Post subject: Bridge:Cannot connect across subnets. |
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I got 2 networks, X on subnet 192.168.1.0 and Y on 192.168.1.0
The bridge has IP 192.168.1.9, and output of route -n says 192.168.1.0 has no gateway and goes through the bridge. I add the same for 192.168.2.0.
The result -- I cannot access the network Y from the box which runs as the bridge.
Nodes on X and Y can communicate to each other but only if they lie on the same subnet, i.e network Y should lie on the subnet 192.168.1.0 in order to communicate to network X. If I set the IP of one node on Y to 192.168.2.0 and add routes with no gateway, then Y cannot communicate to X and opposite. _________________ My blog |
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NeddySeagoon Administrator
Joined: 05 Jul 2003 Posts: 54220 Location: 56N 3W
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Posted: Sat Oct 12, 2013 12:01 pm Post subject: |
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dE_logics,
You need a static route in both directions or change the netmask on both subnets to be /22, rather than /24 but then 192.168.1.x and 192.168.2.x are in the same subnet as are 192.168.0.x and 192.168.3.x
Both ways work.
Oh there is a third way - run NAT between the two subnets but you probably don't want that. _________________ Regards,
NeddySeagoon
Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail. |
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dE_logics Advocate
Joined: 02 Jan 2009 Posts: 2253 Location: $TERM
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Posted: Sat Oct 12, 2013 2:57 pm Post subject: |
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Hi Neddy!
I added route on both ends (nodes on network Y and the box which's the bridge) as follows --
Gentoo box which works as a bridge --
Code: | 0.0.0.0 192.168.1.1 0.0.0.0 UG 217 0 0 eth1_veth
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
192.168.1.0 0.0.0.0 255.255.255.0 U 217 0 0 eth1_veth
192.168.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1_veth |
Routes on network Y --
Code: | 192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
192.168.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 |
However it still doesn't work.
Changing network bits to 22 is not the point here -- I'm trying to bridge 2 separate networks. _________________ My blog |
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Carnildo Guru
Joined: 17 Jun 2004 Posts: 594
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Posted: Mon Oct 14, 2013 11:58 pm Post subject: |
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dE_logics wrote: | Changing network bits to 22 is not the point here -- I'm trying to bridge 2 separate networks. |
The first thing to do is get your terminology correct. A "bridge" connects two pieces of the same subnet. A "router" connects two subnets.
The second thing to do is to activate routing on your system:
Code: | echo "1" >> /proc/sys/net/ipv4/ip_forward |
To make that change survive across reboots, add the line
Code: | net.ipv4.ip_forward = 1 |
to your /etc/sysctl.conf file. |
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dE_logics Advocate
Joined: 02 Jan 2009 Posts: 2253 Location: $TERM
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Posted: Tue Oct 15, 2013 5:01 am Post subject: |
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Carnildo wrote: | dE_logics wrote: | Changing network bits to 22 is not the point here -- I'm trying to bridge 2 separate networks. |
The first thing to do is get your terminology correct. A "bridge" connects two pieces of the same subnet. A "router" connects two subnets. |
No, a router's task is to route packets across multiple (or single) route(s) which includes connecting networks, like subnets. However connecting subnets is the primary task of a bridge. Besides there's no reason why there should not be internetwork communication, or why subnets should not be able to communicate to each other.
The problem on my end, as Neddy pointed out, was that the node (on X) to which I was sending packets to did not have routes added for subnet 192.168.2.0/24, so it could not respond to network Y. _________________ My blog |
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