CentOS - Jul 2015 - Multiple network cards - routing issue?

On Sat, 18 Jul 2015 21:34:27 -0700
Gordon Messmer wrote:
> Does the system work correctly if you don't run those "ip
route" commands?
It's exactly the same.  And what I mean by exactly the same is EXACTLY the
same.

I rebooted the system which should clear out my route commands and whatnot, and
discovered that everything (route -n and ip route show and whatnot) are exactly
the same as before.  Therefore, the ip route and ip rule commands apparently had
no effect whatsoever -- what I got after entering the ip route commands is
exactly what I have without entering those commands.

Interesting.  But since it's still exactly the same, it's still not
working; it still fails in exactly the same way too.

-- 
MELVILLE THEATRE ~ Real D 3D Digital Cinema ~ www.melvilletheatre.com

On 07/18/2015 10:12 PM, Frank Cox wrote:
> Interesting.  But since it's still exactly the same, it's still not
working; it still fails in exactly the same way too.
Yes, but that means you need to start with the standard troubleshooting 
stuff.  Do you have link?  Is the Ethernet cable working?  Do you see 
any traffic if you run "tcpdump -nn -i eth1"? Double-check your IP 
address and gateway in the configuration file. Is the gateway's MAC 
address listed in the output of "arp"?

On Sat, 18 Jul 2015 22:37:30 -0700
Gordon Messmer wrote:
> On 07/18/2015 10:12 PM, Frank Cox wrote:
> > Interesting.  But since it's still exactly the same, it's
still not
> > working; it still fails in exactly the same way too.
> 
> Yes, but that means you need to start with the standard troubleshooting 
> stuff.  Do you have link?  Is the Ethernet cable working? 
[root at audio ~]# ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen
1000
    link/ether 00:26:5a:07:f0:da brd ff:ff:ff:ff:ff:ff
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen
1000
    link/ether 00:26:5a:07:ef:8d brd ff:ff:ff:ff:ff:ff
4: eth2: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:40:05:86:66:4a brd ff:ff:ff:ff:ff:ff
5: sit0: <NOARP> mtu 1480 qdisc noop 
    link/sit 0.0.0.0 brd 0.0.0.0

I double-checked that I had the ethernet cable plugged into the right port on
the server by unplugging it and then eth1 said "NO CARRIER".  As far
as I know, that means that the cable and port are working.


 Do you see > any traffic if you run "tcpdump -nn -i eth1"?

I see no traffic on eth1 with that command until I log into another session and
type "ping google.com".  Then I get this output:

[root at audio ~]# tcpdump -nn -i eth1
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth1, link-type EN10MB (Ethernet), capture size 96 bytes
00:11:00.412188 arp who-has 204.83.15.254 tell 204.83.15.1
00:11:01.412135 arp who-has 204.83.15.254 tell 204.83.15.1
00:11:02.412112 arp who-has 204.83.15.254 tell 204.83.15.1

3 packets captured
3 packets received by filter
0 packets dropped by kernel

 Double-check your IP  address and gateway in the configuration file.

Seems to be correct.
>  Is the gateway's MAC  address listed in the output of "arp"?
Apparently not.

[root at audio ~]# arp
Address                  HWtype  HWaddress           Flags Mask            Iface
192.168.1.1              ether   00:24:01:F3:93:21   C                     eth0
204.83.15.254                    (incomplete)                              eth1

I don't know what that means; this is the first time I ever typed the arp
command.

-- 
MELVILLE THEATRE ~ Real D 3D Digital Cinema ~ www.melvilletheatre.com