What is the IP of the system trying to reach the 192.168.164.2 interface? It sounds like the system may not have a route back to the client. With the default route pointing to the 10.19.175.241 address anything not in a local subnet will get routed out that interface. I've never seen Ubuntu behave differently than Fedora when it comes to routing, not sure what else could be going on there if there are no firewalls involved. --j On Tue, Feb 17, 2009 at 5:04 PM, Venkat Chandra <vc.lists at gmail.com> wrote: > One of the applications that I am working with requires a fairly unorthodox > network configuration. This machine is running Ubuntu 8.10 with all the > latest patches. This has multiple wired network interfaces. > The /etc/network/interfaces file is as under: > > auto lo > iface lo inet loopback > > auto eth0 > iface eth0 inet static > address 10.19.175.242 > netmask 255.255.255.240 > network 10.19.175.240 > broadcast 10.19.175.255 > gateway 10.19.175.241 > dns-nameservers 10.19.173.245 > > auto eth1 > iface eth1 inet static > address 192.168.164.2 > netmask 255.255.252.0 > > The output of netstat -nr is as under: > > Kernel IP routing table > Destination Gateway Genmask Flags MSS Window irtt > Iface > 10.19.175.240 0.0.0.0 255.255.255.240 U 0 0 0 > eth0 > 192.168.164.0 0.0.0.0 255.255.252.0 U 0 0 0 > eth1 > 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 > eth1 > 0.0.0.0 10.19.175.241 0.0.0.0 UG 0 0 0 > eth0 > > > The network cables from these two interfaces terminate on a Cisco 6509 > switch. Another machine of interest is also connected to this switch. Pings > from this other machine to the 192.168.164.2 interface are not returned. > > If I were to do: > > $ sudo route delete default device eth0 > $ sudo route add default gw 192.168.164.1 device eth1 > > then the other machine is able to ping 192.168.164.2. Of course I lose the > ability to reach the 10.19.175.242 interface. > > > I tried the Fedora 10 Live distribution on the same machine. I used the > NetworkManager applet to first configure eth0, checked the connectivity to > that interface before configuring the eth1 interface. I lost connectivity to > the eth0 interface at this point. I then did the following: > > # route delete default device eth1 > # route add default gw 10.19.175.241 device eth0 > > and the routing table: > > [root at localhost ~]# route > Kernel IP routing table > Destination Gateway Genmask Flags Metric Ref Use > Iface > 10.19.175.240 * 255.255.255.240 U 1 0 0 > eth0 > 192.168.164.0 * 255.255.252.0 U 1 0 0 > eth1 > default 10.19.175.241 0.0.0.0 UG 0 0 0 > eth0 > > And I was able to reach both the eth0 and eth1 interfaces at this point > from appropriate machines on the network. > > I tried using a bootable USB Live Ubuntu 8.10, and I repeated the exact > steps I had performed with the F10 and I was only able to reach one of the > interfaces and not both at the same time. I can run tcpdump on the > interfaces separately and I can see ICMP Requests coming in on both the > interfaces but only one of the interfaces responds with an ICMP Reply. > > Any idea why Ubuntu would behave differently? I'd appreciate any > suggestions on what I could try so that both interfaces are reachable > simultaneously. > > Thanks, > Venkat. > > _______________________________________________ > TCLUG Mailing List - Minneapolis/St. Paul, Minnesota > tclug-list at mn-linux.org > http://mailman.mn-linux.org/mailman/listinfo/tclug-list > > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://mailman.mn-linux.org/pipermail/tclug-list/attachments/20090217/ffdb578b/attachment-0001.htm