[TriLUG] problems with multiple interfaces on a RHEL5.5 x64 machine

[Matt Pusateri]

Heath is on track here most likely.  What does netstat -rn show when only eth1 is up versus when eth2 is up.  Also when you are pinging external IP's are you pinging by IP or by hostname?  If it's by hostname, I would suspect that your name servers are getting set in resolv.conf when you get an address via DHCP.

Matt P.

On Nov 8, 2011, at 7:28 PM, Heath Roberts wrote:

> I don't know specifically about linux, but most unix distributions don't
> like having multiple interfaces on the same subnet.
> 
> As to why you have 'external' (by which I assume you mean off your own
> subnet) connectivity with the DHCP address and not the static one: When you
> have the DHCP interface active, it's learning routes (well, at least a
> default route) from DHCP. How are you configuring routes when only the
> static interface is up?
> 
> On Tue, Nov 8, 2011 at 7:20 PM, Warren Myers <volcimaster at gmail.com> wrote:
> 
>> Good evening, all
>> 
>> I am trying to use a statically-assigned address on one interface (eth1) of
>> a server and have a dhcp-assigned address on another interface (eth2) on
>> the same subnet (172.17.11.0/24).
>> 
>> When I setup a static IP for eth1 (following the directions found on
>> 
>> http://www.cyberciti.biz/faq/rhel-centos-fedoracore-linux-network-card-configuration
>> ),
>> I entered the following into `/etc/sysconfig/network-scripts/ifcfg-eth1`:
>> 
>> # ServerEngines Corp. Emulex OneConnect 10Gb NIC (be3)
>> DEVICE=eth1
>> BOOTPROTO=static
>> DHCPCLASS=
>> HWADDR=00:21:5A:9B:00:41
>> IPADDR=172.17.11.203
>> NETMASK=255.255.255.0
>> #TYPE=ethernet
>> ONBOOT=yes
>> 
>> 
>> If eth1 is the only adapter running, I cannot ping *ANY* external IP :(
>> 
>> When eth2 is also running, I can ping external addresses.
>> 
>> `ifconfig` returns the following:
>> 
>> eth1      Link encap:Ethernet  HWaddr 00:21:5A:9B:00:41
>>         inet addr:172.17.11.203  Bcast:172.17.11.255  Mask:255.255.255.0
>>         inet6 addr: fe80::221:5aff:fe9b:41/64 Scope:Link
>>         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>>         RX packets:4747 errors:0 dropped:0 overruns:0 frame:0
>>         TX packets:5495 errors:0 dropped:0 overruns:0 carrier:0
>>         collisions:0 txqueuelen:1000
>>         RX bytes:447100 (436.6 KiB)  TX bytes:1059019 (1.0 MiB)
>>         Memory:fbf60000-fbf80000
>> 
>> eth2      Link encap:Ethernet  HWaddr 00:21:5A:9B:00:42
>>         inet addr:172.17.11.245  Bcast:172.17.11.255  Mask:255.255.255.0
>>         inet6 addr: fe80::221:5aff:fe9b:42/64 Scope:Link
>>         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>>         RX packets:6745 errors:0 dropped:0 overruns:0 frame:0
>>         TX packets:10802 errors:0 dropped:0 overruns:0 carrier:0
>>         collisions:0 txqueuelen:1000
>>         RX bytes:1260318 (1.2 MiB)  TX bytes:12302950 (11.7 MiB)
>>         Memory:fbe40000-fbe60000
>> 
>> 
>> # cat /etc/sysconfig/network
>> HOSTNAME=<redacted>
>> NETWORKING=yes
>> NETWORKING_IPV6=no
>> GATEWAY=172.17.11.1
>> 
>> 
>> Am I missing something super obvious? If so, what is it?
>> 
>> Regards,
>> Warren
>> 
>> --
>> Warren Myers
>> http://warrenmyers.com
>> http://twitter.com/volcimaster
>> http://www.linkedin.com/in/warrenmyers
>> --
>> This message was sent to: Heath Roberts <htroberts at gmail.com>
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> 
> 
> 
> -- 
> Heath Roberts
> htroberts at gmail.com
> -- 
> This message was sent to: M. Pusateri <mpusateri at wickedtrails.com>
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