I'm having a devil of a time: running FC2 through eth0 RCA modem on comcast.net. That connection did something, now instead of being localhost at login, I'm x1-6-04-4f-00 or something like that, which happens to be the hw addy of the eth0. How do I change this, or at least nickname it, to get back to localhost? I'm a newbie wanting to learn! :) Thanks.
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Paul wrote:
I'm having a devil of a time: running FC2 through eth0 RCA modem on comcast.net. That connection did something, now instead of being localhost at login, I'm x1-6-04-4f-00 or something like that, which happens to be the hw addy of the eth0. How do I change this, or at least nickname it, to get back to localhost? I'm a newbie wanting to learn! :) Thanks.
============================================= Never forget another important date again http://AllReminders.net =============================================
paul, you could try this.... redhat--->System Settings--->Networking login as root click DNS tab look at "Host Name" _________________ (mine says "My_World") there you can change the name . if your PC is the only one hooked up, then it shouldn't be a problem. i had to reboot afterwards so you'll probably have to as well. Good luck and let me know if this helped. jim
From James Lawrence's reply to paul@sark.us on Saturday, June 26, 2004
6:07 PM:
Paul wrote:
I'm having a devil of a time: running FC2 through eth0 RCA modem on comcast.net. That connection did something, now instead of being localhost at login, I'm x1-6-04-4f-00 or something like that, which happens to be the hw addy of the eth0. How do I change this, or at least nickname it, to get back to localhost? I'm a newbie
wanting to
learn! :) Thanks.
localhost@localdomain is not really a valid hostname in a networked environment. Comcast has strict internal guidelines requiring unique hostnames thoughout their network. They have set up their DHCP servers to force a unique hostname whenever they find a machine without one (either no name at all or one that is currently in use). I'm not sure which category they group localhost in, but since customers are not allowed to use it the distinction is mute.
Eric Diamond eDiamond Networking & Security eric<at>ediamond[dot]net
On Sat, Jun 26, 2004 at 09:46:17PM -0600, Eric Diamond wrote:
From James Lawrence's reply to paul@sark.us on Saturday, June 26, 2004
6:07 PM:
Paul wrote:
I'm having a devil of a time: running FC2 through eth0 RCA modem on comcast.net. That connection did something, now instead of being localhost at login, I'm x1-6-04-4f-00 or something like that, which happens to be the hw addy of the eth0. How do I change this, or at least nickname it, to get back to localhost? I'm a newbie
wanting to
learn! :) Thanks.
localhost@localdomain is not really a valid hostname in a networked environment. Comcast has strict internal guidelines requiring unique hostnames thoughout their network. They have set up their DHCP servers to force a unique hostname whenever they find a machine without one (either no name at all or one that is currently in use). I'm not sure which category they group localhost in, but since customers are not allowed to use it the distinction is mute.
Erik is correct. note the '@' sign should be a dot.
The key thing here is that each network connection has a name and that the system inherits a name almost as a side effect.
The first interesting line in /etc/hosts looks like:
127.0.0.1 localhost.localdomain localhost
This line names the special case, local loopback interface (lo0). i.e. lo0 is an interface:
One common edit of this line might look like.
127.0.0.1 localhost.localdomain localhost box1.paul.localdomain box1
And now the system admin can use an alias "box1.paul.localdomain" or "box1" for the system. This may confuse things later but, the alias maps back to the 127.0.0.1 address and the localhost.localdomain name. In the file "/etc/sysconfig/network" you might do this with a line that looks like:
HOSTNAME=box1.paul.localdomain
or perhaps
HOSTNAME=box1
When the system boots it picks up the host name and matches it to a line in the hosts file (/etc/hosts;. See /etc/sysconfig/network and eventually all these other files too:
/etc/sysconfig/network/networking/* /etc/sysconfig/network/network-scripts/*
There may be hard links to /etc/hosts that should not be broken. While exceptions apply, Some of us will see:
/etc/sysconfig/networking/profiles/default/hosts
Note the same inode number:
# ls -il /etc/sysconfig/networking/profiles/default/hosts /etc/hosts 6734009 -rw-r--r-- 2 root root 2619 Jun 16 07:30 /etc/hosts 6734009 -rw-r--r-- 2 root root 2619 Jun 16 07:30 /etc/sysconfig/networking/profiles/default/hosts
Timing is important. Names and numbers for the important interfaces mostly need to be in /etc/hosts to bootstrap the process. X-server connections will be made to 127.0.0.1 so this must exist and be correct. Once connected to the internet the domain name service DNS can look up additional host name and IP address pairs as needed. Some of this can be discovered with a broadcast help packet which is how DHCP works.
Next when you connect to Comcast, for your ethernet link, as the connection process begins you first get an additional interface activated (commonly eth0). Next a dynamic host name process (DHCP) fetches an IP address and the public name for this interface. It names it and brings it up. Other network hints for DNS and routing are shared via this DHCP process. If you did not name localhost via the HOSTNAME variable you correctly can expect to get a host name that looks like x1-6-04-4f-00 or something at this stage.
Now you have two named interfaces. One name you appear to have control of on lo0 and the other is assigned to you by your ISP dynamically each time you connect on eth0.
If you attempt to lookup the IP address associated with box1.paul.localdomain you should get 127.0.0.1. If anyone else attempts to look it up they will not get a good answer. This is what I mean that you appear to have control of the host name.
The x1-6-04-4f-00 or something name should work for both internal and external connections. It is this :x1-6-04-4f-00 or something" named interface that your 'services' will use to connect to and from the world. The nature of DHCP is that this will change so you do not need to write it down. You should not expect it to be a constant!
The HOSTNAME= line is important because it decides which name to use for system services even if there are twohundredfortyfive named network interfaces (chill, Linux does not support that many by default).
The key point is that you will commonly have two active network connections: localhost.localdomain on lo0 and another on eth0, genericname.yourisp.toplevel. Again it is the interfaces that have names.
The devices lo0 and eth0 are only two of a long list of names for devices that map to a kernel device driver. On FC1 see /etc/modules.conf:
alias eth0 via-rhine
In FC2 see /etc/modprobe.conf:
alias eth0 via-rhine
If your hardware is different you will see different driver names. If you have multiple network cards you can see multiple lines sort of like this: $ grep eth /etc/mod* /etc/modules.conf:alias eth0 via-rhine /etc/modules.conf:alias eth1 tulip
Again, The key thing to recall is that network connections have names.
<end part A, Lesson 1, chapter 1>
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Eric Diamond -
James Lawrence -
Paul -
Tom Mitchell