The IP trying to reach the 192.168.164.2 interface is 10.19.176.22.<div><br></div><div>I removed the iptables package for good measure after I noticed this problem. No luck. </div><div><br></div><div>I just tried a live Ubuntu 7.10 off of a USB drive and the routing works just fine. At this point, I am fairly certain this is a bug in Ubuntu 8.10 (and also 8.04 LTS). It would be great to have a workaround. Any suggestions are appreciated.</div>
<div><br></div><div>Thanks,</div><div>Venkat. <br><br><div class="gmail_quote">On Tue, Feb 17, 2009 at 7:42 PM, J Cruit <span dir="ltr"><<a href="mailto:j@packetgod.com">j@packetgod.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
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.<br>
<br>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.<br><br>--j<br><br><div class="gmail_quote"><div><div>
</div><div class="Wj3C7c">On Tue, Feb 17, 2009 at 5:04 PM, Venkat Chandra <span dir="ltr"><<a href="mailto:vc.lists@gmail.com" target="_blank">vc.lists@gmail.com</a>></span> wrote:<br>
</div></div><blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex"><div><div></div><div class="Wj3C7c">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. <div>
<br></div>
<div>The <span style="font-family:'courier new',monospace">/etc/network/interfaces</span> file is as under:</div><div><br></div><div><div><div><span style="font-family:'courier new';font-size:12px">auto lo</span></div>
<div><span style="font-family:'courier new';font-size:12px">iface lo inet loopback</span></div><div><span style="font-family:'courier new';font-size:12px"><br>
</span></div><div><span style="font-family:'courier new';font-size:12px">auto eth0</span></div><div><span style="font-family:'courier new';font-size:12px">iface eth0 inet static</span></div>
<div><span style="font-family:'courier new';font-size:12px"> address 10.19.175.242</span></div><div><span style="font-family:'courier new';font-size:12px"> netmask 255.255.255.240</span></div>
<div><span style="font-family:'courier new';font-size:12px"> network 10.19.175.240</span></div><div><span style="font-family:'courier new';font-size:12px"> broadcast 10.19.175.255</span></div>
<div><span style="font-family:'courier new';font-size:12px"> gateway 10.19.175.241</span></div><div><span style="font-family:'courier new';font-size:12px"> dns-nameservers 10.19.173.245</span></div>
<div><span style="font-family:'courier new';font-size:12px"><br></span></div><div><span style="font-family:'courier new';font-size:12px">auto eth1</span></div>
<div><span style="font-family:'courier new';font-size:12px">iface eth1 inet static</span></div><div><span style="font-family:'courier new';font-size:12px"> address 192.168.164.2</span></div>
<div><span style="font-family:'courier new';font-size:12px"> netmask 255.255.252.0</span></div><div><br></div></div><div>The output of <span style="font-family:'courier new',monospace">netstat -nr</span> is as under:</div>
<div><span style="font-family:'courier new',monospace"><br></span></div><div><div><span style="font-family:'courier new',monospace">Kernel IP routing table</span></div>
<div><span style="font-family:'courier new',monospace">Destination Gateway Genmask Flags MSS Window irtt Iface</span></div><div><span style="font-family:'courier new',monospace">10.19.175.240 0.0.0.0 255.255.255.240 U 0 0 0 eth0</span></div>
<div><span style="font-family:'courier new',monospace">192.168.164.0 0.0.0.0 255.255.252.0 U 0 0 0 eth1</span></div><div><span style="font-family:'courier new',monospace">169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth1</span></div>
<div><span style="font-family:'courier new',monospace">0.0.0.0 10.19.175.241 0.0.0.0 UG 0 0 0 eth0</span></div><div><br></div><div><br></div><div>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. </div>
<div><br></div><div>If I were to do:</div><div><span style="font-family:'courier new',monospace"><br></span></div><div><span style="font-family:'courier new',monospace">$ sudo route delete default device eth0<br>
</span></div><div><span style="font-family:'courier new',monospace">$ sudo route add default gw 192.168.164.1 device eth1 </span><br></div><div><br></div><div>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. </div>
<div><br></div><div><br></div><div>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:</div>
<div><span style="font-family:'courier new',monospace"><br></span></div><div><span style="font-family:'courier new',monospace"># route delete default device eth1<br>
</span></div><div><span style="font-family:'courier new',monospace"># route add default gw 10.19.175.241 device eth0</span></div><div><br></div><div>and the routing table:</div><div><span style="font-family:'courier new';font-size:12px"><br>
</span></div><div><span style="font-family:'courier new',monospace">[root@localhost ~]# route </span></div><div><span style="font-family:'courier new',monospace">Kernel IP routing table </span></div>
<div><span style="font-family:'courier new',monospace">Destination Gateway Genmask Flags Metric Ref Use Iface</span></div><div><span style="font-family:'courier new',monospace">10.19.175.240 * 255.255.255.240 U 1 0 0 eth0 </span></div>
<div><span style="font-family:'courier new',monospace">192.168.164.0 * 255.255.252.0 U 1 0 0 eth1 </span></div><div><span style="font-family:'courier new',monospace">default 10.19.175.241 0.0.0.0 UG 0 0 0 eth0 </span></div>
<div><span style="font-family:'courier new';font-size:12px"><br></span></div><div><span style="font-size:12px"><span style="font-family:arial,helvetica,sans-serif">And I was able to reach both the eth0 and eth1 interfaces at this point from appropriate machines on the network.</span></span></div>
<div> <br></div><div>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. </div>
<div><br></div><div>Any idea why Ubuntu would behave differently? I'd appreciate any suggestions on what I could try so that both interfaces are reachable simultaneously.</div><div><br></div><div>Thanks,</div><div>Venkat. <br>
</div></div></div>
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