telnet on local LAN question

[Craig White]

On Mon, 2011-08-15 at 22:04 -0700, Paul Allen Newell wrote:
> Greetings
> 
> I am trying to figure out how to get communication between my F14 boxes 
> on a local wired LAN. The best test case I can come up with to prove 
> that I don't know what I am doing wrong is telnet.
> 
> Each machine has a /etc/hosts looking like (where <name> is the machine 
> name and <other> is any other machine:
> +++
> 127.0.0.1 <name>    localhost.localdomain    localhost 
> <name>.localdomain    localhost4
> ::1 <name>    localhost6.localdomain6    localhost6 <name>.localdomain
> 
> 192.168.2.10 <other1>.localdomain <other1>
> 192.168.2.11 <other2>.localdomain <other2>
> 192.168.2.12 <other3>.localdomain <other3>
> +++
> 
> For the other machines, its name is removed in the 192.168.10.x list and 
> 192.168.2.13 <name>.localdomain <name> is added
> 
> Each machines has a /etc/sysconfig/network of:
> +++
> NETWORKING=yes
> HOSTNAME=<name>.localdomain
> NTPSERVERARGS=iburst
> +++
> 
> I didn't see any reference to <name> or <otherX> in 
> /etc/sysconfig/network-scripts/ifcfg-eth0, so I am not including it ... 
> if there should be something, I'd love to know! I can't think of any 
> other place for <otherX> or <otherX>.localdomain, but that's out of 
> ignorance as I haven't encountered this sort of problem before.
> 
> The splash screen for all machines is <name>.localdomain. The command 
> hostname returns <name>.localdomain.
> 
> Ping works great between all of the machines for both <otherX> and 
> <otherX>.localdomain, lists the 192.168.10.x address like a happy camper 
> should
> 
> But a telnet <otherX> 25 or telnet <otherX>.localdomain 25 fails.
> 
> I can't tell if I need to add information about the other machines 
> somewhere else on <name> or if they really are known but something is 
> blocking it.
> 
> I also can't use mail/mailx between the machines. I noticed that 
> mail/mailx always resolves <otherX> to <otherX>.localdomain (and sending 
> to self is resolved to <name>.localdomain), so I changed network to use 
> the localdomain suffix and added it in /etc/hosts before the instance of 
> <other>. Neither telnet or mail/mailx worked with just <name>, so I am 
> pretty certain that I didn't break anything by changing <name> to 
> <name>.localdomain.
> 
> Some machines were already using hostname of <name>.localdomain and my 
> records aren't good enough to know how I specified the name of the 
> machine when I installed F14 (it never was an issue as everything worked 
> until I tested mail/mailx and telnet so I never documented exactly how I 
> should set machine name on install).
> 
> It seems that the telnet problem is a simpler one than the mail/mailx 
> and if I can at least get telnet working, then I am closer to getting 
> mail/mailx working.
> 
> Any suggestions?
----
by default, the typical smtp servers aren't listening for connections on
any interface other than 127.0.0.1 - which smtp daemon are you using? Is
it configured to listen on the 192.168.2.x interface?

As far as name resolution goes, unless you have a local dns server, you
will have to manage /etc/hosts file on each computer if you want
computers know each other by name. I much prefer using DNS over managing
separate files on separate computers but that is for you to decide.

localdomain is fine - some people also use .local (which comports with
other service providers such as avahi) - it really doesn't matter as
long as what you use is consistent from machine to machine and fits DNS
standards (alpha-numerics and dashes)

Also - I think you sort of discovered, on redhat systems (and Fedora is
of this class)... /etc/sysconfig/network
 NETWORKING=yes
 HOSTNAME=lin-workstation.azapple.com
 NTPSERVERARGS=iburst
is a reasonable configuration

Craig


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