on 1/29/2008 5:24 PM Jason Pyeron spake the following:
without-----Original Message-----From: centos-bounces@xxxxxxxxxx [mailto:centos-bounces@xxxxxxxxxx] On Behalf Of Les MikesellSent: Tuesday, January 29, 2008 18:25 To: CentOS mailing list Subject: Re: Network routesYou probably want to remove the default route through NE.TW.KB.1 and add routes for the specific networks that you can reach though it. Normally routing is done toward a destination network/addressregard to the route of a packet you might be replying to. As for an 'outage', how do you define/detect the outage? Normally if you wantroutes to bedetermined dynamically you would set up a routing protocol with the next-hop routers - or for simple failover the alternative gateway routers might be configured via hsrp or vrrp to have a floating IP address that the rest of the LAN uses as the default gateway address.Droping the failover requirements, pings still do not respond off the local subnet. [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
But none of the destinations have a gateway address. So all of the traffic is trying to go from every interface to the default gateway. Do both interfaces go out the same router?As an example in my system, I have a local interface and a wan interface. Only the wan interface needs to use the default route, as it is the only interface that talks to the outside world. But my internal interface has routes to other private networks through IPSec tunnels on other routers.
So the internal interface has multiple routes and each has a gateway address of the router that handles that route.
Are your network-a and network-b addresses actually public addresses or rfc-1918 private addresses?
It took me a while to get mine right, so don't feel bad.
[root@host20 ~]# tcpdump -n 'icmp[0] = 8 or icmp[0] = 0' tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes 20:27:02.789177 IP 192.168.1.114 > 192.168.1.20: icmp 64: echo request seq 0 20:27:02.789277 IP 192.168.1.20 > 192.168.1.114: icmp 64: echo reply seq 0 20:27:03.786470 IP 192.168.1.114 > 192.168.1.20: icmp 64: echo request seq 256 20:27:03.786509 IP 192.168.1.20 > 192.168.1.114: icmp 64: echo reply seq 256 20:27:04.778574 IP 192.168.1.114 > 192.168.1.20: icmp 64: echo request seq 512 20:27:04.778612 IP 192.168.1.20 > 192.168.1.114: icmp 64: echo reply seq 512 20:27:05.778262 IP 192.168.1.114 > 192.168.1.20: icmp 64: echo request seq 768 20:27:05.778299 IP 192.168.1.20 > 192.168.1.114: icmp 64: echo reply seq 768 20:27:08.032006 IP CO.MC.A.ST > NE.TW.RKB.IP1: icmp 64: echo request seq 0 20:27:09.026055 IP CO.MC.A.ST > NE.TW.RKB.IP1: icmp 64: echo request seq 256 20:27:10.032333 IP CO.MC.A.ST > NE.TW.RKB.IP1: icmp 64: echo request seq 512 20:27:11.025881 IP CO.MC.A.ST > NE.TW.RKB.IP1: icmp 64: echo request seq 768 20:27:13.022155 IP CO.MC.A.ST > NE.TW.RKB.IP1: icmp 64: echo request seq 1280 13 packets captured 13 packets received by filter 0 packets dropped by kernel Why are there no replies being sent? -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- - - - Jason Pyeron PD Inc. http://www.pdinc.us - - Sr. Consultant 10 West 24th Street #100 - - +1 (443) 269-1555 x333 Baltimore, Maryland 21218 - - - -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- This message is for the designated recipient only and may contain privileged, proprietary, or otherwise private information. If you have received it in error, purge the message from your system and notify the sender immediately. Any other use of the email by youis prohibited.
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