  | | | Dual NIC Cards | Dual NIC Cards 2006-04-14 - By Bret Stern
Back > -- --Original Message-- -- > From: redhat-install-list-bounces@(protected) > [mailto:redhat-install-list-bounces@(protected)]On Behalf Of Rick Stevens > Sent: Friday, April 14, 2006 10:18 AM > To: Getting started with Red Hat Linux > Subject: Re: Dual NIC Cards > > > On Fri, 2006-04-14 at 11:02 -0700, Rick Stevens wrote: > > On Thu, 2006-04-13 at 23:18 -0600, karlp@(protected) wrote: > > > On Thu, April 13, 2006 10:41 pm, Bret Stern said: > > > > > > > > I have dual network cards in a new box > > > > i'm putting together. Fedora 4 > > > > > > Me, too. > > > > I have machines with up to 6. > > > > > > Both cards are set to activate on boot, but > > > > only one starts on boot. The other will start > > > > manually. > > > > > > Mine both start on boot. > > > > > > > > > > > One card has a static ip. > > > > One card gets assigned an ip address (dhcp) > > > > > > I assigned static IPs to both. That may be why one of yours > doesn't start. > > > Is the one that starts the static or DHCP assigned nic? > > > > > > > > > > > Can both cards have the same hostname? > > > > (go ahead have fun with that question) > > > > > > They have to have the same hostname. I don't see an option in > the gui setup > > > to give a different hostname for each card. > > > > Ah, fertile ground for misunderstandings. You must keep in mind that > > there are differences between hostnames, nodenames and FQDNs (fully > > qualified domain names). > > > > A machine can only have one hostname (as displayed by "hostname" or > > "uname -n"), and is the true hostname. By default, it's "localhost" or > > the FQDN "localhost.localdomain". > > > > A machine _may_ have a nodename under NIS/NIS+ and is set and displayed > > by the "domainname" command. Unless you run NIS/NIS+, you needn't worry > > about this, and if you do run it, 95 times out of 100 you'll set it to > > be the same as the hostname. > > > > Now, each IP address on the machine _may_ have a FQDN associated with > > it, but it's not required. Each FQDN can have a number of DNS aliases > > associated with it (called CNAMEs in DNS parlance). > > > > Confused yet? > > > > > > I've heard you can only have a gateway address > > > > on one nic card. Is this correct? > > > > > > Yes, it's correct. > > > > Uhm, this must be clarified. There is only one _default_ gateway, and > > that is the "route of last resort". In other words, if you try to send > > traffic to a node that is not on a network directly connected to one of > > your NICs (as determined by the IP address/netmask combination) AND you > > don't have a route forcing traffic for the remote node's network through > > one of your NICs, THEN the traffic goes out the default gateway. If you > > do have a route for the network, it goes out the NIC that has that > > route. > > > > As an example, assume a machine with two NICs. eth0 has an IP of > > 192.168.0.2. eth1 has an IP of 10.0.0.2. The default gateway is > > 192.168.0.1 (obviously on eth1). > > DOH! That should read "(obviously on eth0)." That's what happens when > your boss is talking to you while you compose responses! >
So you only assign a gateway entry to ONE of the nic cards? > > > > Now, let's say you try to ping 10.24.1.1. The traffic will go out eth0, > > since the default gateway (actually, the default route) is on eth0. > > However, you really want any traffic for 10.0.0.0/8 to go out on eth1. > > You set up a static route: > > > > route add -net 10.0.0.0 netmask 255.0.0.0 dev eth1 > > > > Now, any traffic for the 10.0.0.0/8 network will go out eth1. You > > can repeat that for as many networks (or hosts, if the netmask is /32) > > as you wish on each NIC (well, up to some practical limit). > > > > -- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- -- > > - Rick Stevens, Senior Systems Engineer rstevens@(protected) - > > - VitalStream, Inc. http://www.vitalstream.com - > > - - > > - If this is the first day of the rest of my life... - > > - I'm in BIG trouble! - > > -- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- -- > > > > __ ____ ____ ____ ____ ____ ____ ____ ____ ____ > > Redhat-install-list mailing list > > Redhat-install-list@(protected) > > https://www.redhat.com/mailman/listinfo/redhat-install-list > > To Unsubscribe Go To ABOVE URL or send a message to: > > redhat-install-list-request@(protected) > > Subject: unsubscribe > -- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- -- > - Rick Stevens, Senior Systems Engineer rstevens@(protected) - > - VitalStream, Inc. http://www.vitalstream.com - > - - > - IGNORE that man behind the keyboard! - > - - The Wizard of OS - > -- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- -- > > __ ____ ____ ____ ____ ____ ____ ____ ____ ____ > Redhat-install-list mailing list > Redhat-install-list@(protected) > https://www.redhat.com/mailman/listinfo/redhat-install-list > To Unsubscribe Go To ABOVE URL or send a message to: > redhat-install-list-request@(protected) > Subject: unsubscribe
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