[plug] Adding PPP

[Leon Brooks]

Shackleton, Kevin wrote:
> I have bought a modem and an ISP account, to overcome problems getting
> out through our firewall and because our Exchange server seems to be
> down a lot lately (though not today!).  Must be because it's supporting
> nearly 1000 users! Wow.

This machine (mail.smileys.net) supports several hundred, as well as
being proxy, name, web and FTP server for up to 20 users at once, and
it's a non-event. P266+96M+4.3G+really-horrid-Oak-PCI-VGA-card.

> So now I need to set up on my Linux PC (RH5.0) the PPP protocol.  Also
> I'd like to try out using the machine as a gateway. (To see how -
> obviously this would circumvent our firewall if I left the eth0 line
> connected).

I use mkdir /etc/ppp/peers, make a file in there named example with
something like this in it:

/dev/ttyS1
115200
lock
defaultroute
crtscts
connect "chat -vf /etc/ppp/peers/example.chat"

...and then make example.chat:

REPORT CARRIER
ABORT BUSY
ABORT "NO DIALTONE"
ABORT "NO CARRIER"
ABORT VOICE
TIMEOUT 10
"" ATZ
OK ATDT####-####
TIMEOUT 75
CONNECT ""
TIMEOUT 15
ogin:--ogin: ########
assword: \q########

Replace ###es with dialin number, username and password, respectively.
Your dialin is probably not called "example" either. (-:

Now (chmod +s /sbin/pppd), any user can "pppd call example" to dial, and
"killall pppd" to hangup (but must be _same_ user or root to hang up).
man pppd for details.

> Looking at adding PPP to the existing LAN configuration, I've run into
> problems straight away - the file /etc/resolv.conf has the entries:
>         search agric.wa.gov.au
>         nameserver <our nameserver>
> while the HOWTO says it should say:
>         domain <isp domain>
>         nameserver <isp nameserver>

Well, change it, dear Liza, dear Liza... (-: always make copies before
editing! :-)

> Dos anyone know about setting up PPP without trashing eth0?  Also, when
> using something like Netscape for mail, how do you specify the transport
> protocol to use?

I make several files /etc/ppp/peers/resolve.conf.example and so on, and
add a line to the pppd script which says:

	welcome /etc/ppp/peers/example.welcome

...and put something like this in [whatever].welcome:

#!/bin/sh
cp /etc/ppp/peers/resolv.conf.[whatever] /etc/resolv.conf

Since this is run as root, one must be careful what one does in it.