simple linux routing question
I have 7 network cards. eth1 brings my network connection in. They each have their own bridge vmbrX. eth1 gets vmbr0 for right now. If I bring up vmbr3 (eth3) via dhclient, I lose my network connection. Is it necessary to put the other 6 network connections on a different subnet from my production network? Not sure how this works exactly.
Here is my routing table before and after bringing up eth3:
and /etc/network/interfaces:
I'm wanting to use these interfaces for dynamips, each of them having an independent network connection capable of reaching the internet. If someone could point me in the right direction I'd be grateful.
Here is my routing table before and after bringing up eth3:
labserver:~# route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.1.0 * 255.255.255.0 U 0 0 0 vmbr0 default 192.168.1.1 0.0.0.0 UG 0 0 0 vmbr0 labserver:~# route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.1.0 * 255.255.255.0 U 0 0 0 vmbr0 192.168.1.0 * 255.255.255.0 U 0 0 0 vmbr3 default 192.168.1.1 0.0.0.0 UG 0 0 0 vmbr3 default 192.168.1.1 0.0.0.0 UG 0 0 0 vmbr0
and /etc/network/interfaces:
# network interface settings auto lo iface lo inet loopback auto eth0 iface eth0 inet manual iface eth1 inet manual iface eth2 inet manual iface eth3 inet manual iface eth4 inet manual iface eth5 inet manual iface eth6 inet manual auto vmbr0 iface vmbr0 inet static address 192.168.1.10 netmask 255.255.255.0 gateway 192.168.1.1 bridge_ports eth1 bridge_stp off bridge_fd 0 auto vmbr1 iface vmbr1 inet manual bridge_ports none bridge_stp off bridge_fd 0 auto vmbr2 iface vmbr2 inet manual bridge_ports eth2 bridge_stp off bridge_fd 0 auto vmbr3 iface vmbr3 inet manual bridge_ports eth3 bridge_stp off bridge_fd 0 auto vmbr4 iface vmbr4 inet manual bridge_ports eth4 bridge_stp off bridge_fd 0 auto vmbr5 iface vmbr5 inet manual bridge_ports eth5 bridge_stp off bridge_fd 0 auto vmbr6 iface vmbr6 inet manual bridge_ports eth6 bridge_stp off bridge_fd 0
I'm wanting to use these interfaces for dynamips, each of them having an independent network connection capable of reaching the internet. If someone could point me in the right direction I'd be grateful.
Climb a mountain, tell no one.
Comments
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Forsaken_GA Member Posts: 4,024does vmbr3 actually have a link back to 192.168.1.1? If not, that's why you're losing connectivity. When you bring eth3 up, it's creating another default route out vmbr3, which is essentially black holing your traffic. If that's the case, then that's your fault, having a dhcp server set a default gateway that can't be reached through that interface is a no no.
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ehnde Member Posts: 1,103Forsaken_GA wrote: »does vmbr3 actually have a link back to 192.168.1.1? If not, that's why you're losing connectivity. When you bring eth3 up, it's creating another default route out vmbr3, which is essentially black holing your traffic. If that's the case, then that's your fault, having a dhcp server set a default gateway that can't be reached through that interface is a no no.
That's what has me baffled...eth0/vmbr1 and eth3/vmbr3 are both connected to the same switch, which is connected to my router doing the internet routing/nat/dhcp. I'll go back and review how I have these cables running and see if what you have suggested may be the cause.Climb a mountain, tell no one. -
Forsaken_GA Member Posts: 4,024Hold on, so you have two seperate interfaces connected to the same network segment?
If so, you have an arp problem. By default, Linux responds to arp requests for all of it's interfaces out all of it's interfaces, so if you have two interfaces connected to the same subnet.. that becomes a problem.
You need to do some research into the arp_filter kernel setting -
ehnde Member Posts: 1,103OK, will do. Thanks again for pointing me in the right direction.Climb a mountain, tell no one.
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ehnde Member Posts: 1,103Just added this to /etc/sysctl.conf:
net.ipv4.conf.vmbr0.arp_filter = 1 net.ipv4.conf.vmbr1.arp_filter = 1 net.ipv4.conf.vmbr2.arp_filter = 1 net.ipv4.conf.vmbr3.arp_filter = 1 net.ipv4.conf.vmbr4.arp_filter = 1 net.ipv4.conf.vmbr5.arp_filter = 1 net.ipv4.conf.vmbr6.arp_filter = 1
I restarted networking, didn't work. Restarted the server, still no go. But then I logged into my router (the one doing DHCP/nat for my home network) and saw this:
192.168.1.10 00:25:22:8A:31:94
192.168.1.15 00:25:22:8A:31:94
Of course my home router only sees the switch. Surely it shouldn't have problems cooperating with a switch, though.Climb a mountain, tell no one. -
ehnde Member Posts: 1,103Now I'm trying this: Ubuntu Linux - multiple NICs, same LAN... ARP responses always go out a single NIC - Server Fault but still no luck.
Right now in sysctl.conf I have:net.ipv4.conf.all.arp_ignore=1 net.ipv4.conf.all.arp_announce=2 net.ipv4.conf.all.arp_filter=0
Climb a mountain, tell no one. -
ehnde Member Posts: 1,103It's been suggested I manually create route maps using LARTC style ip, but I'm afraid this is a bit over my headClimb a mountain, tell no one.