multiple network interfaces questions, RHEL 3 new install

[Bob McClure Jr]

On Fri, Jan 21, 2005 at 02:08:26PM -0600, Chuck Campbell wrote:
> Our new dual Opteron server (x86_64) running RHEL3, update 3 (Taroon)
> has a K8s pro motherboard with on board networking.  It also has two
> broadcom Gigabit Ethernet NICs.
> 
> The system sees eth0 as the motherboard 100bT, and eth1 adn eth2 as the
> two Broadcom interfaces.  
> 
> Questions:
> I want to use one GB interface to talk to the other cluster machines,
> the other GB interface to be the samba server, and not mix traffic between
> them.
> 
> I'd like to use the 100bT interface for mail only.

Are they on separate subnets?  That's the only way you prevent a mix
of traffic

> Where can I find info on setting things up this way (or is it impossible) ?
> I know that I can bind samba to a particular interface, but how do I control
> what interface talks to the local intranet and what interface only talks
> to other cluster machines?

Only by subnetting.  The port (Samba, mail, et al.) is irrelevant to
the ethernet device.  The network interface card cares only about IP
address.

> Will they need to be different sub-nets to make this work?

Yes, if you don't want to mix differing traffic on the same wire.

> The output of netstat -r is here:
> [root at cluster_master etc]# netstat -r
> Kernel IP routing table
> Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
> 172.17.2.0      *               255.255.255.0   U         0 0          0 eth0
> 172.17.2.0      *               255.255.255.0   U         0 0          0 eth1
> 172.17.2.0      *               255.255.255.0   U         0 0          0 eth2
> 169.254.0.0     *               255.255.0.0     U         0 0          0 eth2
> default         172.17.2.1      0.0.0.0         UG        0 0          0 eth0
> 
> I don't know what or where the 169.254.0.0 address is...
> 
> The output of ifconfig -a is here:
> [root at cluster_master etc]# ifconfig -a
> eth0      Link encap:Ethernet  HWaddr 00:E0:81:2C:74:33
>           inet addr:172.17.2.29  Bcast:172.17.2.255  Mask:255.255.255.0
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:928092 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:218612 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:1000
>           RX bytes:1134994584 (1082.4 Mb)  TX bytes:40338127 (38.4 Mb)
>           Interrupt:18 Base address:0xbc00 Memory:feafb000-feafb038
>  
> eth1      Link encap:Ethernet  HWaddr 00:E0:81:2C:73:86
>           inet addr:172.17.2.30  Bcast:172.17.2.255  Mask:255.255.255.0
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:88001 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:70 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:1000
>           RX bytes:6950013 (6.6 Mb)  TX bytes:4480 (4.3 Kb)
>           Interrupt:24
>  
> eth2      Link encap:Ethernet  HWaddr 00:E0:81:2C:73:87
>           inet addr:172.17.2.31  Bcast:172.17.2.255  Mask:255.255.255.0
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:85921 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:70 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:1000
>           RX bytes:6791141 (6.4 Mb)  TX bytes:4480 (4.3 Kb)
>           Interrupt:25

You can have each service on a different IP address (and so, on a
different NIC), but it's pointless if you want to keep traffic for
service A from getting in the way of traffic for service B.  It's all
still on the same network.

> <snippage>
> 
> -- 
> ACCEL Services, Inc.| Specialists in Gravity, Magnetics |  1(713)993-0671 ph.
>  2401 Fountain View |   and Integrated Interpretation   |  1(713)993-0608 fax
>      Suite 320      |                                   |
>  Houston, TX, 77057 |          Chuck Campbell           | campbell at accelinc.com
>                     |  President & Senior Geoscientist  |

Cheers,
-- 
Bob McClure, Jr.             Bobcat Open Systems, Inc.
robertmcclure at earthlink.net  http://www.bobcatos.com
Wise men still seek Him.