Kernel mode PPPoE or Penguins DO NOT ROAR!!!

Message

Jeld · Post by **Jeld** » Fri Aug 22, 2003 9:48 pm

Reason: The installation guide suggests using rp-pppoe package to connect to a PPPoE DSL provider. I have gone that road for a while and found several problems:

There is no /etc/init.d script for the service. I have seen
one on these forums, but it doesn't solve the second problem, which is
rp-pppoe package is a software redirector wasting prescious CPU cycles on redirecting PPP traffic to ethernet controller, while there is a perfectly
( well... individual results may vary ) working kernel module doing the same thing.
The setup is much too complex.
rp-pppoe web site name is ridiculous.

So, given all of these, and multiple posts about PPPoE on these forums, I have decided to make this small HOWTO.
-----------------------------------------------------------------------------------

Recompile the kernel with support for PPPoE redirection

Code: Select all

make menuconfig
And then under Network Support

<M>     PPP (point-to-point protocol) support  
[ ]       PPP multilink support (EXPERIMENTAL)                         
[*]       PPP filtering                               
<M>       PPP support for async serial ports                           
<M>       PPP support for sync tty ports                               
<M>       PPP Deflate compression  
<M>       PPP BSD-Compress compression                             
<M>       PPP over Ethernet (EXPERIMENTAL) 

mount /boot
make dep clean bzImage modules modules_install install

I recommend compiling PPP support as modules, since if it crashes ( happens in 2.6 series ) it will not take the whole system with it.

Emerge PPP daemon
Code: Select all
```
emerge ppp
```

Edit /etc/conf.d/net.ppp0
Set the following:

Code: Select all

PEER="Your ISP name"
DEBUG="no"
PERSIST="yes"      # You want to reconnect if the connection is dropped
ONDEMAND="no"
MODEMPORT="eth0" # Wierd isn't it
LINESPEED=""  # Doesn't matter
INITSTRING=""
DEFROUTE="yes"
HARDFLOWCTL="no"
ESCAPECHARS="no"
PPPOPTIONS=""
USERNAME=""
PASSWORD=""
NUMBER="" 

PEERDNS="yes" # Optional

AUTOCFGFILES="no"  # This one is important, if you do not set it to no, it will screw up your whole config.

Edit /etc/ppp/options to be the following one line
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```
plugin pppoe.so
```
Edit your /etc/ppp/pap-secrets to be the following
Code: Select all
```
"your user name" "your ISP name" "your password"
```
for example:
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```
"asdf@earthlink.net" "Earthlink" "blah1234"
```
Make sure to use the same ISP name as in net.ppp0 PEER setting
Create /etc/ppp/peers/(Your ISP name) ( e.g. /etc/ppp/peers/Earthlink )
Code: Select all
```
touch /etc/ppp/peers/Earthlink
```
Edit /etc/init.d/net.ppp0. Put the following at the start of the file
Code: Select all
```
depend() {
    need net.eth0
}
```
This is so that it only starts after the ethernet is up.

[green]Optional[/green] Edit /etc/ppp/ip-up script.
There are several things you can put there, most importantly updating your
/etc/resolve.conf if you are using usepeerdns setting, registering with DynDNS service and updating the /etc/hosts file. Here is mine that does all of these things.

Code: Select all

# Wait for the interface to be up.
while [ -e /proc/sys/net/ipv4/conf/ppp0 ]; do sleep 1; done
                                                                                                    
# Setup domain name resolution
echo -n "domain " > /etc/resolv.conf
cat /etc/dnsdomainname >> /etc/resolv.conf
cat /etc/ppp/resolv.conf >> /etc/resolv.conf
                                                                                                    
                                                                                                    
# Update dynamic DNS records
dyndnsupdate -u user:password -a $4 -h myhostname
                                                                                                    
# Update /etc/hosts file
sed -i "s/.*myhostname /${4}\tmyhostname /" /etc/hosts

If you are using fetchmail you might put a call to that here, or start other internet services which require an internet connection.

Start the service
Code: Select all
```
/etc/init.d/net.ppp0 start
```
Put it in startup
Code: Select all
```
rc-update add net.ppp0 default
```

That's it folks. Enjoy. Hope it works for you.

plate · Post by **plate** » Sun Aug 24, 2003 12:14 pm

Great stuff! Thanks a lot.

Moved from Networking & Security.

uriahheep__ · Post by **uriahheep__** » Wed Oct 01, 2003 3:55 pm

I followed all of the above instructions, but it doesn't work:

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Oct  1 08:37:20 [pppd] Plugin pppoe.so loaded.
Oct  1 08:37:20 [pppd] PPPoE Plugin Initialized
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module escape
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module escape
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module crtscts
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module crtscts
Oct  1 08:37:20 [modprobe] modprobe: Safe mode parameter starts with '-'
Oct  1 08:37:20 [modprobe] modprobe: Safe mode parameter starts with '-'
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module nocrtscts
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module nocrtscts
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module cdtrcts
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module cdtrcts
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module nocdtrcts
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module nocdtrcts
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module xonxoff
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module xonxoff
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module modem
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module modem
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module local
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module local
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module sync
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module sync
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module vj
Oct  1 08:37:20 [modprobe] modprobe: Can't locate module vj
Oct  1 08:37:20 [pppd] pppd 2.4.1 started by root, uid 0
Oct  1 08:37:20 [pppd] Sending PADI
Oct  1 08:37:20 [pppd] HOST_UNIQ successful match
Oct  1 08:37:20 [pppd] HOST_UNIQ successful match
Oct  1 08:37:20 [pppd] Got connection: 268
Oct  1 08:37:20 [pppd] Connecting PPPoE socket: 00:90:1a:40:90:12 6802 eth0 0x8088488
Oct  1 08:37:20 [pppd] Using interface ppp0
Oct  1 08:37:20 [pppd] Connect: ppp0 <--> eth0
Oct  1 08:37:20 [pppd] Couldn't increase MTU to 1500.
Oct  1 08:37:20 [pppd] Couldn't increase MRU to 1500
Oct  1 08:37:20 [pppd] Couldn't increase MRU to 1500
Oct  1 08:37:20 [pppd] LCP terminated by peer
Oct  1 08:37:20 [pppd] Couldn't increase MTU to 1500.
Oct  1 08:37:20 [pppd] Couldn't increase MRU to 1500
Oct  1 08:37:23 [pppd] Connection terminated.
Oct  1 08:37:23 [pppd] Doing disconnect

I've also tried setting the MTU/MRU to 1492 and it does the exact same thing. And yes, rp-pppoe works:

Code: Select all

Oct  1 08:40:02 [pppd] Plugin pppoe.so loaded.
Oct  1 08:40:02 [pppd] PPPoE Plugin Initialized
Oct  1 08:40:02 [pppd] pppd 2.4.1 started by root, uid 0
Oct  1 08:40:02 [pppd] Using interface ppp0
Oct  1 08:40:02 [pppd] Connect: ppp0 <--> /dev/ttyp1
Oct  1 08:40:03 [pppoe] PPP session is 630
Oct  1 08:40:03 [pppd] local  IP address 68.121.244.15
Oct  1 08:40:03 [pppd] remote IP address 10.1.1.1
Oct  1 08:40:03 [pppd] primary   DNS address 206.13.28.12
Oct  1 08:40:03 [pppd] secondary DNS address 206.13.29.12

I'd much prefer to use the method that Jeld suggests, but I can't seem to figure out why I'm getting the "LCP teminated by peer" after it successfully connects.

I'm using the 2.4.1-r11 version of pppd on a 2.4.20 kernel...

uriahheep__ · Post by **uriahheep__** » Wed Oct 01, 2003 8:07 pm

Now it's working. For some reason, it wants

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name "username@isp.net" # Yes, my real email address goes here and no, this isn't it...

in the options file as well as the "plugin pppoe.so" line.

Not sure why this is, since I set up the /etc/conf.d/net.ppp0 file and /etc/ppp/peers with the name of my ISP as per above... Same with the pap-secrets file.

Wayne- · Post by **Wayne-** » Mon Oct 20, 2003 1:49 am

The reason for that is the way PPP hands over login name on the PPPoE protocol. On the PPPoE side, the ISP is part of the user's login name, so you are "thisuser@thisisp". With that, the master server receiving your authentication request can direct it to the proper ISP, who will then verify that you are one of his customers. The ISP settigs in the PPP config are there just to sort thing out so you can dial to one "isp" instead of another one.

bone · Post by **bone** » Thu Dec 04, 2003 9:47 pm

BUMP.. someone was a duplicate post.

bone · Post by **bone** » Thu Dec 04, 2003 9:48 pm

I cant seem to get this going at all.

I have literally set everything up the way the first post said, the only things in my /etc/conf.d/net.ppp0 file are the following

[Code]
PEER="swbell"
DEBUG="no"
PERSIST="yes" # You want to reconnect if the connection is dropped
ONDEMAND="no"
MODEMPORT="eth0" # Wierd isn't it
LINESPEED="" # Doesn't matter
INITSTRING=""
DEFROUTE="yes"
HARDFLOWCTL="no"
ESCAPECHARS="no"
PPPOPTIONS=""
USERNAME=""
PASSWORD=""
NUMBER=""

PEERDNS="yes" # Optional

AUTOCFGFILES="no" # This one is important, if you do not set it to no, it will screw up your whole config.
[/Code]

and I only have two lines in my /etc/ppp/options file:
[Code]
plugin pppoe.so
lock
[/Code]

When I type /etc/init.d/net.ppp0 start, i get an error that seems to be showing my the syntax of pppd, and some of the options that should be passed to it.

I didnt do anything special to the emerge of ppp, could this be why?

HELP.

P.S. Sorry, I am at work or I could give you the exact error that the /etc/init.d/net.ppp0 start command generated.

UPDATE: I just realized that I didnt have the username, password, or number fields set in my /etc/conf.d/net.ppp0. could this be the problem? I know what to set the username and password to, but what do I set the number to?

Jeld · Post by **Jeld** » Thu Dec 04, 2003 10:27 pm

Do you have PPP over Ethernet support in the kernel?

bone · Post by **bone** » Thu Dec 04, 2003 10:39 pm

Yes, I do have all the correct stuff in the kernel. The thing here is I have did this before (for the past two years) but always used rp-pppoe. I have begun to hate the overhead/CPU cycles that the rp-pppoe software implementation is using and decided to try this other way.

bone · Post by **bone** » Thu Dec 04, 2003 11:08 pm

See this post: http://forums.gentoo.org/viewtopic.php? ... light=pppd

Thats the same exact error message that I got. I guess I will try the options that he tried and see if I can get this thing going.

Thanks

den_RDC · Post by **den_RDC** » Wed Dec 31, 2003 4:31 am

It worked here, although i did use the german options file in order to get it work (and i realized my german is in a very bad chape). anyway, i still got some problems : some websites just stall. I reasearched it and it seems this has something to da with an MSS value (whatever that means). Rp-pppoe does mss-clamping to get around whatever the issue is, but i can't seem to find anything remotly similar. Any clues?

voosuz · Post by **voosuz** » Wed Dec 31, 2003 2:28 pm

den_RDC wrote:It worked here, although i did use the german options file in order to get it work (and i realized my german is in a very bad chape). anyway, i still got some problems : some websites just stall. I reasearched it and it seems this has something to da with an MSS value (whatever that means). Rp-pppoe does mss-clamping to get around whatever the issue is, but i can't seem to find anything remotly similar. Any clues?

i had exactly the same problem. i spent a few hours messing around with MTU/MRU and whatever else i could find but couldn't get it working either. in the end i just put the adsl-start command in the init.d script and am now using the rp-pppoe daemon again. ugly, i know, but at least it works as expected.

den_RDC · Post by **den_RDC** » Fri Jan 02, 2004 8:48 pm

well, i finally found a solution that does the mss clamping trick.
A oneliner :

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iptables -I FORWARD -p tcp --tcp-flags SYN,RST SYN -m tcpmss --mss 1400:1536 -j TCPMSS --clamp-mss-to-pmt

Execute this command after your iptables firewall script (if u do it before the script it might not work if your script flushes the tables). This will not work for the local host (the router/firewall itself). If that's a problem, just execute it again but replace FORWARD with OUTPUT. This also needs the right iptables module present or compiled in the kernel (don't know wich one, i enabled them all on my setup).

For more information visit http://blue-labs.org/howto/mtu-mss.php
It explains nicely what's causing this problem (braindead admins

)

Kihaji · Post by **Kihaji** » Thu Jan 08, 2004 7:33 pm

den_RDC wrote:It worked here, although i did use the german options file in order to get it work (and i realized my german is in a very bad chape). anyway, i still got some problems : some websites just stall. I reasearched it and it seems this has something to da with an MSS value (whatever that means). Rp-pppoe does mss-clamping to get around whatever the issue is, but i can't seem to find anything remotly similar. Any clues?

The actuall issue here is that PPPOE adds 8 bits on top of your current MSS value (maximum segment size btw), so with your MSS set to 1500, it is really being sent out at 1508, which a lot of sites will not accept. Lowering it 1492 sends it out at 1500, which is what you want.

Now if I can only get this working...

Jeld · Post by **Jeld** » Fri Jan 16, 2004 8:46 pm

Unfortunately, I have switched providers, and now I do not have PPPoE guiney pig to do evil experiments on. I will not be able to provide any support for my HOWTO. Sorry.

den_RDC · Post by **den_RDC** » Sun Mar 21, 2004 1:11 am

Kihaji wrote:
den_RDC wrote:It worked here, although i did use the german options file in order to get it work (and i realized my german is in a very bad chape). anyway, i still got some problems : some websites just stall. I reasearched it and it seems this has something to da with an MSS value (whatever that means). Rp-pppoe does mss-clamping to get around whatever the issue is, but i can't seem to find anything remotly similar. Any clues?
The actuall issue here is that PPPOE adds 8 bits on top of your current MSS value (maximum segment size btw), so with your MSS set to 1500, it is really being sent out at 1508, which a lot of sites will not accept. Lowering it 1492 sends it out at 1500, which is what you want.

Now if I can only get this working...

Actually, you are confusing MSS and MTU.
Besides, sending a PPPOE packet with 1508 bytes out over ethernet would not work, since ethernet (at least 10/100mbit) has a maximum frame size of 1518 bytes, wich results in a maximum MTU of 1500 bytes. (gigabit ethernet can send bigger frames, the so called jumbo-frames)

fincoop · Post by **fincoop** » Mon Mar 29, 2004 12:00 am

I got this howto to work, thanks very much. I found that the TCP MSS clamping via Iptables is mostly effective, but this forums page wouldn't load for example, so I dropped the MSS to 1300.

Now, what about UDP or other IP connections?

There has to be a way to lower the MTU/MRU to a lower value successfully?

Thanks

fincoop · Post by **fincoop** » Wed Mar 31, 2004 12:32 am

fincoop wrote:I got this howto to work, thanks very much. I found that the TCP MSS clamping via Iptables is mostly effective, but this forums page wouldn't load for example, so I dropped the MSS to 1300.

Now, what about UDP or other IP connections?

There has to be a way to lower the MTU/MRU to a lower value successfully?

Thanks

Went back to RP... can't deny that it works very well.

Paranoid · Post by **Paranoid** » Mon Apr 05, 2004 11:31 pm

Well just wanted to post that I had success with the above listed config plus adding the name="username@isp" to the options file. Very happy, haven't noticed any stalling as I haven't clamped the mss-but then in rp-pppoe I had clamping turned off anyways. Perhaps it's just my imagination but web page loads seem to be a little snappier now too

Thanks for the good info.

Although I do have one complaint-the ppp kernel plugin is now named rp-pppoe.so, WTF?

OhSh33t · Post by **OhSh33t** » Thu Apr 08, 2004 2:09 pm

fincoop wrote:
fincoop wrote:I got this howto to work, thanks very much. I found that the TCP MSS clamping via Iptables is mostly effective, but this forums page wouldn't load for example, so I dropped the MSS to 1300.

Now, what about UDP or other IP connections?

There has to be a way to lower the MTU/MRU to a lower value successfully?

Thanks

Went back to RP... can't deny that it works very well.

I don't know if this helps. As I'm just lurking through the forums right now. But you should be able to set the mtu on any interface you want via.... E.G.

Code: Select all

# /sbin/ifconfig ppp0 mtu 1492
or
# ifconfig ppp0 mtu 1492
then
# ifconfig ppp0 
(you'll notice that the mtu is now 1492)
When I'm root I use full path for all commands. Personal choice.. So the second one works just like the first. man ifconfig might have some additional info.

When I had a pppoe connection I had to make sure all machines behind the firewall also had there MTU's set to 1492.

Hope that helps. Please let me know. I will be helping a friend setup pppoe
on a really old Intel MMX 200MHz machine.. I keep here'ing the rp-pppoe chews up allot of cpu cycles.. I think that would be bad for him.

Thanks,

-=LeXuS=- · Post by **-=LeXuS=-** » Sun May 09, 2004 12:31 pm

Hi,

ive got a small problem with this howto... all things seems to work, but after starting net.ppp0 the script runs into this line and waits.... and wait....

Is it a typo?

while [ -e /proc/sys/net/ipv4/conf/ppp0 ]; do sleep 1; done

I think it shout be

while [ ! -e /proc/sys/net/ipv4/conf/ppp0 ]; do sleep 1; done

Bye

AndCycle · Post by **AndCycle** » Sat Jun 05, 2004 11:26 am

some update to this topic

with current net-dialup/rp-pppoe ebuild v3.5

1. There is no /etc/init.d script for the service.

we got /etc/init.d/rp-pppoe in current ebuild

2. rp-pppoe package is a software redirector wasting prescious CPU cycles on redirecting PPP traffic to ethernet controller, while there is a perfectly
( well... individual results may vary ) working kernel module doing the same thing.
3. The setup is much too complex.

no longer a real problem in current ebuild,
it's very simple to do this job to make rp-pppoe using kernel mode now

I compiled the kernel with ppp support like Jeld said as module,

emerge rp-pppoe and ppp,

modified /etc/ppp/pppoe.conf, searching for LINUX_PLUGIN,
changed it into "LINUX_PLUGIN=/usr/lib/pppd/2.4.2/rp-pppoe.so"
(gentoo put this plugin at different path

)

and it works

hoschi · Post by **hoschi** » Sun Jun 06, 2004 2:25 pm

hello,
do you know whats going wrong?

her is a pic of what linux says me

http://www.hottemptation.org/night/error02.png

AndCycle · Post by **AndCycle** » Sun Jun 06, 2004 4:16 pm

hoschi wrote:hello,
do you know whats going wrong?

her is a pic of what linux says me
http://www.hottemptation.org/night/error02.png

oops, sorry I didn't mention that,
kernel mode can be directly used by rp-pppoe now,
so no longer need to modified or using the net.ppp

the only step I take from Jeld is recompile kernel with ppp modules and emerge ppp,
rest of work is modified /etc/ppp/pppoe.conf, adsl-setup, then /etc/init.d/rp-pppoe start

hoschi · Post by **hoschi** » Sun Jun 06, 2004 5:19 pm

yes,
it is a error in the howto!

edit the /etc/ppp/options, and add:
plugin pppoe.se
name "your user name"
lock

and so you don't need rp-pppoe, ok, it is now only comsetic, but a emerge less to do

ps: ich wrote three bash-scipts, for start, stop and status and now ist really my "own" way for getting a internet-connection

thank you, bye