[2941] in RedHat Linux List
RE: Continuing networking problems...
daemon@ATHENA.MIT.EDU (Al Longyear)
Wed Nov 6 06:29:05 1996
From: Al Longyear <longyear@sii.com>
To: "'redhat-list@redhat.com'" <redhat-list@redhat.com>
Cc: "'kbf@phy.duke.edu'" <kbf@phy.duke.edu>
Date: Wed, 6 Nov 1996 03:27:19 -0800
Resent-From: redhat-list@redhat.com
Reply-To: redhat-list@redhat.com
>----------
>From: Kyle Ferrio[SMTP:kbf@phy.duke.edu]
>Sent: Tuesday, November 05, 1996 5:52 PM
>To: redhat-list@redhat.com
>Subject: Continuing networking problems...
>
>Ok. I -must- be missing something obvious.
>
>Local mail wasn't getting delivered.
>So I added a default route in the netcfg "Routing" window:
>
>Default Gateway: 127.0.0.1
>Default Gateway Device: lo
DON'T DO THAT!!!!!
>
>stop and restart networking ; still no mail delivery
>
>Worse, ppp no longer works. pppd just hangs.
NO KIDDING. That is what happens when you do that! PPPD won't be the
only program to just 'hang' if you attempt to make a default route and
don't have an external router.
>I guess the newly installed default route is intercepting the pppd
>defaultroute, and goes no place.
The pppd process has code within it to not replace an existing default
route. This is done for a reason, which may be not as significant now as
it was a couple of years ago when it was started.
The reason is that if you permit a user to run the pppd process and they
use a bogus IP address for the peer system the only real damage that
they could do is to generate a host route to that IP address UNLESS they
also decided to change the default route to that location as well. So,
in order to prevent the default route from being destroyed, we prevented
the default route from being added if there is presently an existing
default route. The theory is that the administrator would have
configured the proper default route during the system startup and it is
not up to the pppd process to change it.
>So let me rephrase my question. I want to be able to do local mail
>delivery all the time and ppp only when needed.
1. Create a bogus hostname. The hostname does not need to be the name
which corresponds to any name associated with an IP address in the DNS
tables. You don't need to change the hostname.
2. Create an entry in the /etc/hosts file with a bogus IP address, such
as 10.10.10.10 (this is a valid IP address reserved for local networks.)
Assign your hostname to this IP address.
3. Get rid of the default route. Do not use one. Let the pppd process
add the default route as needed.
If your IP address assigned to you by the service provider varies
dynamically with each call then you can not directly receive SMTP mail
from the service provider. You need to use POP or IMAP protocols to
retrieve it. You can use fetchmail to help with this process if you
want. Fetchmail is on http://www.ccil.org/~esr.
If the IP address is fixed, that is does not change with each call, then
you should be able to receive SMTP mail. However, you need to make sure
that either sendmail or smail or qmail (whichever MTA -- mail transport
agent -- that you are using) knows that the name associated with that IP
address is one of the names for this computer and the mail destined for
this RHS (right hand side) of the address is 'local'. For sendmail, put
the name in the /etc/sendmail.cw file or on the "Cw" macro line in the
/etc/sendmail.cf file.
Sorry, I don't use the other MTAs so you will have to ask someone else
where the information would go for them.
Then you need to verify that the delivery agent for sendmail is working
-- if you use sendmail. This would be a program called 'mail-local' or
'procmail' or 'deliver'. You should be able to run it with just the name
of the local user as one of the parameters (see the Mlocal mailer in
/etc/sendmail.cf. The $u is the user name.) Then just type the headers,
followed by a blank line, followed by some text, followed by Ctrl-D
(Control + D) to signal EOF. The mail should be delivered to the mail
spool.
The 'qmail' mailer has its own delivery agent.
For future reference:
There are usenet groups dedicated to the mail system. You will probably
have much better response if you ask the appropriate usenet group --
comp.mail.smail, comp.mail.misc (for the delivery agents), or
comp.mail.sendmail.
>
>How should the Routing / Hosts / Names in netcfg be set?
>
>I had all this working under slackware in the past, but I'm reluctant to
>muddle things up by mixing in old (possibly inappropriate) conig files.
>
--
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