Static IP

[Rick Stevens]

Scott Mertens wrote:
> On Tue, 2005-04-12 at 10:21 -0700, Rick Stevens wrote:
> 
>>Scott Mertens wrote:
>>
>>>On Tue, 2005-04-12 at 10:00 -0700, Rick Stevens wrote:
>>>
>>>
>>>>Scott Mertens wrote:
>>>>
>>>>
>>>>>New Linux User:  Red Hat Enterprise Linux ES release 4 (Nahant)
>>>>>
>>>>>I am in the process of setting up Printer sharing on this Linux box for
>>>>>WIN XP users. I think some of my problems might be resolved if I can set
>>>>>up a static IP for this box.  Currently it gets one from a Linksys
>>>>>router connected to ISP.
>>>>>
>>>>>How can I tell Linux to use a static IP, but use DNS and other info
>>>>>provided by ISP/Linksys router?
>>>>
>>>>First off, get into the router and write down the DNS info it uses.
>>>>Also check the router's "DHCP Pool" (those are the addresses that the
>>>>DHCP server will give out) and the router's IP address and netmask.
>>>>
>>>>Run "redhat-config-network" (or "RedHatIcon->System Settings->Network"
>>>
>>>>from the Gnome GUI) and configure the NIC for a fixed IP address.  You
>>>
>>>>will want to select a fixed IP that is NOT in the DHCP pool for the
>>>>router.  Your netmask will probably be 255.255.255.0, but use the one
>>>>you saw that the router was using.  Your default gateway will be the
>>>>router (usually 192.168.0.1) and you'll put in the DNS servers you
>>>>grabbed from the router.  That should be it.
>>>
>>>
>>>Thanks, I'll give that a try.
>>
>>Go for it, Scott.  We'll be waiting for a status report.
> 
> 
> Is there just a file I can edit?  My practice is to always make a backup
> of files before editing, and I'm not sure the GUI will do that.  Also
> running the following as you suggest throws an error.
> 
> [root at RHServer01 ~]# redhat-config-network
> -bash: redhat-config-network: command not found

That's odd.  Hmmm.  Try "system-config-network".  One or the other
should be in /usr/bin.

Anyway, yes, you can edit files if you wish.  You're interested in
these two files:

	/etc/sysconfig/network
	/etc/sysconfig/network-scripts/ifcfg-eth0

/etc/sysconfig/network contains three lines generally.  Here's a typical
file:

	NETWORKING=yes
	HOSTNAME=hostname.domainname.tld
	GATEWAY=xxx.xxx.xxx.xxx

The values in there should be pretty obvious.  Put your desired hostname
as the value of the "HOSTNAME=" line, and the IP address of your gateway
in the "GATEWAY=" line (as I said, your gateway is probably
192.168.0.1, but use whatever the router's LAN port's address is).

The second file, /etc/sysconfig/network-scripts/ifcfg-eth0, sets up the
specifics for your NIC.  The only data that is REQUIRED in that file
are the following:

	DEVICE=eth0
	BOOTPROTO=static
	IPADDR=xxx.xxx.xxx.xxx
	NETMASK=yyy.yyy.yyy.yyy
	ONBOOT=yes

Make sure you set the "DEVICE=" to the proper device.  If you only have
one NIC, then "eth0" is the right value (it should match the name of the
file).

"BOOTPROTO=static" is what makes the device use a static IP rather than
one from DHCP (which is triggered by "BOOTPROTO=dhcp").  Obviously, you
put your desired IP address in the "IPADDR=" line and your netmask in
"NETMASK=".

The final line, "ONBOOT=yes" tells the system to bring up this interface
at boot time.

Once you've got all that set up, do "/etc/rc.d/init.d/network restart"
and the system should switch over to your new network settings.

Hope that helps.
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- Rick Stevens, Senior Systems Engineer     rstevens at vitalstream.com -
- VitalStream, Inc.                       http://www.vitalstream.com -
-                                                                    -
-           What is a "free" gift?  Aren't all gifts free?           -
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