on 1/29/2008 2:53 PM Jason Pyeron spake the following:
-----Original Message----- From: centos-bounces@centos.org [mailto:centos-bounces@centos.org] On Behalf Of Ross S. W. Walker Sent: Tuesday, January 29, 2008 17:38 To: CentOS mailing list Subject: RE: [CentOS] Network routes
Jason Pyeron wrote:
I am unable to ping NE.TW.RKB.IP1 from an outside network. Other machines which do not have access or routes for NET.WOR.KA.0 respond
just fine.
How do I get it to respond on both NET.WOR.KA.0 and NE.TW.RKB.0 given all default traffic should go through NET.WOR.KA.1 unless it is in reply to traffic from NE.TW.RKB.1 or there is an outage.
[root@host20 ~]# route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface NET.WOR.KA.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1 192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 NE.TW.RKB.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth1 0.0.0.0 NET.WOR.KA.1 0.0.0.0 UG 0 0 0 eth1 0.0.0.0 NE.TW.RKB.1 0.0.0.0 UG 20 0 0 eth0
[root@host20 ~]# ifconfig eth0 Link encap:Ethernet HWaddr 00:17:31:0F:04:AE inet addr:NE.TW.RKB.IP1 Bcast:NE.TW.RKB.255 Mask:255.255.255.0 eth0:pn Link encap:Ethernet HWaddr 00:17:31:0F:04:AE inet addr:192.168.1.20 Bcast:192.168.1.255 Mask:255.255.255.0 eth1 Link encap:Ethernet HWaddr 00:01:03:E9:42:D0 inet addr:NET.WOR.KA.IP2 Bcast:NET.WOR.KA.255 Mask:255.255.255.0 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0
You can have only 1 default route.
You can use RIP or some other routing protocol to advertise defualt routes to the host from the gateways based upon route availability or weight, or you can deploy reverse NAT'ing on the gateways so external IPs will be masqueraded as the internal IP of the gateway and thus be routed to the appropriate gateway based on which IP they arrived on.
-Ross
But I have 2 physical network cards, on 2 different networks. Should they not both have default routes?
You would think so, but it will confuse the system so bad that traffic won't know where to go. The default route is the route that packets need to take to leave your network to enter the outside world. Every thing under your control should have static routes of some kind, or a routing daemon.