I am having some headaches getting more than one IP address to work properly on a machine. I can make it work with neither multiple nics or aliased interfaces.
In both cases, connectivity to the same subnet works just fine. I do not have any connectivity to other subnets, however.
Symptoms:
eth0 is on one subnet, and eth1 is on another.
When I ping either interface from their respective subnets, all is well.
When I send a ping to eth0 from another subnet, all is well. The default gateway is located on the same subnet as eth0.
When I send a ping to eth1 from another subnet, I get no response.
When I send a packet from eth0 to another subnet while sniffing, it leaves eth0 and gets a response, and all is well.
When I send a packet from eth1 to another subnet while sniffing, it leaves -eth0- and recieves a response on eth1. It does not seem to get the recieved packet internally, however.
Ifconfig output:
eth0 Link encap:Ethernet HWaddr 00:50:DA:B5:BE:81
inet addr:164.229.232.10 Bcast:164.229.232.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:44370390 errors:0 dropped:0 overruns:0 frame:0
TX packets:45054387 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
Interrupt:11 Base address:0xe000
eth1 Link encap:Ethernet HWaddr 00:02:B3:2A:C7:A9
inet addr:164.229.233.2 Bcast:164.229.233.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:864453 errors:0 dropped:0 overruns:0 frame:0
TX packets:38706 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
Interrupt:10 Base address:0xe000
Here are some juicy bits of route -C -n
two standard entries for eth0, showing default gateway.
Source Destination Gateway Flags Metric Ref Use Iface
164.229.232.10 164.229.127.4 164.229.232.1 0 0 757 eth0
164.229.1.50 164.229.232.10 164.229.232.10 l 0 0 2566 lo
After performing a dns lookup from both addresses, i get these relevant entries:
164.229.14.3 164.229.232.10 164.229.232.10 l 0 0 653 lo
164.229.233.1 164.229.233.2 164.229.233.2 il 0 0 0 lo
164.229.233.2 164.229.14.3 164.229.232.1 0 0 1 eth0
164.229.14.3 bound for 164.229.233.2 never appears in the routing table.
I am stumped as to why this does not work, especially considering I have an iptables box at home. Enabling IP forwarding in /proc/sys/net/ipv4/ip_forward doesnt help anything. Any ideas?
Ben Lavender
System Administrator, Newsouth Communications
NCTAMS LANT DET NOLA