Stephen A. Fuqua (SAF) is a Bahá'í, programmer, and conservation and interfaith advocate in the DFW area of Texas.

November 9, 2003

Configuring RP-PPPOE in Red Hat Linux 9

I finally got DSL again a few months ago, after 2 years of dial-up. Worked like a charm on my iBook, but not so on the Linux box. Actually, it wasn't so bad at first, but the DNS lookups were taking forever. Then it started dropping carrier. Often. To the point where, after a few minutes of using the computer, it was dropping every few seconds. Here's how I fixed it.

Relevant System Parameters

  • Red Hat Linux 9
  • tulip and rt1839 chips in two network cards (for masquerading, of course)
  • SBC Yahoo! DSL

Symptoms

  • dropping carrier every few seconds
  • can't see the internal network (ping can't find the computer), even with all ip filtering turned off

Hardware

I thought it was a hardware issue at first, for when I removed one of my cards everything worked. I could either connect to the outside world or to the inside world without a hitch. So I went out and bought a cheap DLink card to replace the SMC I had taken out.

That didn't solve it. So I went Googling.

Googling

I found one post out there that looked helpful, suggesting that there is a timeout conflict going on in the ifcfg-ppp0 file. One of the listed symptoms was a strange error message reading "Inactivity timeout... something wicked happened on session 4214," which I hadn't at first noticed in my log file. So I tried their suggestion of shortening the LCP_INTERVAL.

Much to my surprise, this didn't work either. But I had a feeling I was on the right path. And then I remembered that I have a DSL connection at work that has never timed out. I forget about it because I never have to do anything with that box other than log in periodically to install security updates.

So I SSHed over, tried to look at the ifcfg-ppp0, and was stumped. No ifcfg-ppp0. (box = Mandrake 7 upgraded to 8). But I did find a file called pppoe-config, I think, in /etc/ppp/. And this file had the settings I wanted. And indeed, it had some very different timeout numbers. I copied these over, and voíla, I've not had a problem since!

The Settings

So the thing that did it was changing both the PPPOE_TIMEOUT and the LCP_TIMEOUT. Here's (most of) the end-product in my ifcfg-ppp0:

USERCTL=no
BOOTPROTO=dialup
NAME=DSLppp0
DEVICE=ppp0
TYPE=xDSL
ONBOOT=yes
PIDFILE=/var/run/pppoe-adsl.pid
FIREWALL=NONE
PING=.
#PPPOE_TIMEOUT=20
LCP_FAILURE=3
#LCP_INTERVAL=80
LCP_INTERVAL=20
PPPOE_TIMEOUT=80
CLAMPMSS=1412
CONNECT_POLL=6
CONNECT_TIMEOUT=60
DEFROUTE=yes
SYNCHRONOUS=no
ETH=eth0
PROVIDER=DSLppp0
USER=redacted
PEERDNS=yes