I have, a machine running RHEL ES 4.7 with 2 physical interfaces.
eth0 Link encap:Ethernet HWaddr 00:14:22:1C:B4:EA inet addr:10.7.13.61 Bcast:10.7.13.255 Mask:255.255.255.0 inet6 addr: fe80::214:22ff:fe1c:b4ea/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:590936429 errors:0 dropped:0 overruns:0 frame:0 TX packets:590246457 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:361946964 (345.1 MiB) TX bytes:3358327885 (3.1 GiB)
eth1 Link encap:Ethernet HWaddr 00:14:22:1C:B4:EB inet addr:10.254.214.16 Bcast:10.254.214.255 Mask:255.255.255.0 inet6 addr: fe80::214:22ff:fe1c:b4eb/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:423509 errors:0 dropped:0 overruns:0 frame:0 TX packets:19440 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:35948215 (34.2 MiB) TX bytes:2850651 (2.7 MiB)
lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:115612666 errors:0 dropped:0 overruns:0 frame:0 TX packets:115612666 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:96931918 (92.4 MiB) TX bytes:96931918 (92.4 MiB)
By default both interfaces route through the default gateway.
$ route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 10.7.13.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 10.254.214.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1 0.0.0.0 10.7.13.1 0.0.0.0 UG 0 0 0 eth0
The LAN, 10.254.214.0/24 that eth1 is a part of, is configured to not route at all. (Actually it's a VLAN, if that's germane). However, when I remove the route entry with:
# route del -net 10.254.214.0 netmask 255.255.255.0
I lose connectivity with the nodes on the LAN. When I do an $ nmap -sP 10.254.214.0/24
the only thing that shows up is Host 10.254.214.16 appears to be up which is the IP address of eth1.
I shouldn't need a routing gateway to reach these devices. In addition, even when the routing entry is there (or not) a ping from eth1 $ ping -I eth1 10.7.13.1
gives me destination unreachable, so the entry is pointless. BTW, $ ping -I eth0 10.7.13.1
works fine as it should.
I guess it's not a big deal. If it works don't fix it. But I'm still curious. Any ideas? === Al