Category Archives: PPPoE

Extending PPPoE access network with network bridge

Linux, Networking, PPPoE, Technical

In a situation, I had to extend my PPPoE network over a wireless bridge. I do not want to have nor maintain 2 PPPoE servers. I didn’t bother failed to understand how PPPoE works and made a wireless bridge without WDS. When one user log in from the bridged side of the network, it works flawlessly. When more users are trying to log in, the user which logged in earlier gets disconnected. Apparently this is caused by MAC address problem[1]. From the PPPoE server’s side, users logging in from the bridged side of the network have the same MAC address which is the bridge device’s MAC address. From the users’ side, they are able to see correct MAC address of every device on the other side of the network. The PPPoE server gets confused when it sends PPPoE packets because multiple users have the same MAC address and there is no way for the server to direct reply to individual user.

[1]Wireless AP is connected to the side of the network where the PPPoE server is connected to, and wireless client is connected to the other side of the network. Every device connected to the same side of the wireless AP gets the wireless client’s MAC address for every device connected over the wireless bridge, however every device over the bridge gets to see the real MAC address of every device connected to the same side of the wireless AP. I believe that if I interchange the wireless AP and client (so now PPPoE server is connected to the wireless client instead), it may work properly since the PPPoE server will get the correct MAC address of all devices over the bridge. Devices connected to the wireless AP obviously will get the same MAC address for the PPPoE server and PPPoE users connected to the same side of the wireless client, but the most important thing is that the PPPoE users over the bridge can communicate properly with the PPPoE server. Since this is a one-to-many and many-to-one situation, this should work, but not for many-to-many situation. This explanation sounds quite confusing due to my limited English. If you could rewrite this part, please let me know.

RP-PPPoE server problem in Fedora Core 5, 6, Fedora 7, 8

Linux, Networking, PPPoE, Technical

Since Fedora Core 5, pppoe-server that comes with rp-pppoe RPM package has always been broken. Someone actually filed a bug report, but unfortunately there was no response. Apparently the problem is caused by ppp conflicting with syslogd. If you stop syslogd and klogd, then pppoe-server will run properly. Fedora Core 4 does not have this problem though. I’m not sure if the newly released Fedora 7 has got this issue sorted out. I’m guessing that they haven’t.

If you have installed Fedora 7 and found out that the issue has been fixed, please let me know ASAP. Thanks! 🙂

Update (Jul 03, 2007): Problem confirmed in Fedora 7.

Update (Mar 14, 2008): Problem fixed as stated on bugzilla ticket.

PPPoE Server HOWTO for MikroTik RouterOS 2.9

MikroTik, Networking, PPPoE, RouterOS, Technical

If you wish to run a PPPoE server, MikroTik RouterOS provides a convenient way to set one up in a few minutes (with built-in traffic shaping feature too!). Previously I used Fedora Core for my PPPoE servers, but I couldn’t find a working solution to keep ghost PPPoE sessions from bogging down my Linux server. I tried MikroTik DOM with RouterOS to replace my Linux-powered PPPoE servers, so far the results are very good.

Below is a mini guide that may be able to help you get your PPPoE server running in a few minutes using RouterOS.

First, make sure that your RouterOS server’s WAN connectivity has been properly configured. Remember that you need at least 2 network interface cards (NICs). This guide assumes that both NICs are ethernet — ether1 and ether2. If you haven’t set anything up on the new system, let me help you with the checklist: (based on my experience, the following issues are the most common)

  • Make sure that the Internet-facing NIC has an IP address assigned on it and the default gateway is set (/ip route add gateway=…)
  • If NAT is used, ensure that src-nat/masquerade firewall rule has been added (/ip firewall nat …) and it is working properly

Once you have verified the server’s connectivity, create a PPP profile (/ppp profile add name=”pppoe-profile” local-address=10.1.1.1 dns-server=… rate-limit=128k/128k). Every user account that uses this profile will get 128Kbps upload and download limit. If you wish to have different types of accounts (for example some customers pay for 256Kbps), create a new PPP profile (change the rate-limit attribute).

Next, create a user account assigned to the new PPP profile (/ppp secret add name=”andryan” password=”test” service=pppoe profile=”pppoe-profile” remote-address=10.1.1.2). When this user logs in successfully, this user gets assigned 10.1.1.2. To dynamically assign IP addresses, there is an example here.

Finally, create a PPPoE server instance (/interface pppoe-server server add service-name=”pppoe1″ interface=ether2 one-session-per-host=yes default-profile=”pppoe-profile”) and enable it. Now your RouterOS PPPoE server is ready to answer PPPoE requests and authenticate your PPPoE clients. 🙂

Good luck!

References:
http://www.mikrotik.com/testdocs/ros/2.9/interface/pppoe.php