Tomato 1.23 PPPoE Disconnection

Discussion in 'Tomato Firmware' started by mike91k, Jan 19, 2009.

  1. mike91k

    mike91k Addicted to LI Member

    Hi there,

    Can somebody help me as I don't know what to do with the router which disconnects from time to time. The router is installed in an apartment with 20 units and perhaps around 30 users. I checked with the ISP and they confirmed that it wasn't because of them as the line is doing all okay.

    This is what I see in the log every time the disconnection happens.

    Jan 19 17:55:41 gm-router daemon.warn pppoe[15032]: LCP appears to be disconnected (pending: 5).
    Jan 19 17:55:41 gm-router redial[15031]: WAN down. Reconnecting...
    How do I turn on the PPoE debugging ?
  2. der_Kief

    der_Kief Super Moderator Staff Member Member

    This is from the Tomato changelog :
    Some PPPoE logging is now optional. See Admin/Logs to re-enable.

    Last jear i had similar problems and after alot of testing the problem appear to be a inactivity timeout from my provider (15min) ! Altought my ISP assured its not the problem by them.
    So dont feel sure what your ISP tell you !

  3. mike91k

    mike91k Addicted to LI Member

    As I have checked, the ISP only disconnect clients every 24 hour. There's no disconnection due to inactivity. However, the usage in the apartment is quite high so the router can hardly idle.

    I checked in Admins/Logs, the option for PPPoE was already selected. I thought I would be able to see more detailed and technical information on PPPoE instead of just connection/disconnect information.
  4. der_Kief

    der_Kief Super Moderator Staff Member Member

    You can try and set debug_pppoe=1 and see if this still works. Jon has implemented this once in a testing version.
    Maybe you should also go through the corresponding FAQ section here.

  5. mike91k

    mike91k Addicted to LI Member

    Okay, now I can see more logging details on PPPoE. I thought that the WRT54G might be malfunctioning, so I replaced it with a new one, which is flashed to tomato 1.23. Still, there's a disconnection.

    I have replaced the ADSL modem with a spare one, again, the disconnection is still there.

    I have attached the logs along with this post. Please help....anyone!

    Note: For security reason, the external IP addresses are masked.

    Attached Files:

  6. pfoomer

    pfoomer LI Guru Member

    Line Quality


    have you considered it may be a line quality or interference problem, which is causing the modem to disconnect?

    You will need to get access to the web page for the ADSL modem, and see if you can get the line quality levels.
  7. mike91k

    mike91k Addicted to LI Member

    I have already checked the line quality with the ISP. They confirmed that it's all good. I personally also logged on to the ADSL modem to see the SNR value, which turned out to be an average of 31, for which I believe is okay.
  8. pfoomer

    pfoomer LI Guru Member



    31dB, if for down stream is good, so if its not the line, is there a recent source of interference, have you recently moved cables?

    Apparently some device (halogen lamps for instance) can affect ADSL communications.
  9. Planiwa

    Planiwa Network Guru Member

    I have very similar problems. I too am looking for better diagnostic information.

    What happened immediately before:

    What is behind such messages as:

    From what/where/why/how?

    The following may be of some help (i.e. monitoring the modem's stats and logs live):

    How to access bridged modem through router:

    router: (change router to be on different subnet as modem)
    modem : plugged into router's WAN port ; router handles PPPoE

    iptables -I POSTROUTING -t nat -o vlan1 -d 192.168.[B]1[/B].0/30 -j MASQUERADE
    ip addr add 192.168.[B]1[/B].2/30 dev vlan1 brd +

    (this will log a message:
    Jan 21 01:01:09 ROUTER kernel: vlan1: add 01:00:5e:00:00:01 mcast address to master interface)

    Now you should be able to access the modem by http(s), ssh, telnet, from the LAN, or the router, or the universe via the router, as applicable.
  10. mike91k

    mike91k Addicted to LI Member

    Nope, I didn't move any cables. Infact, I have tested by removing all other equipments such as WAP54G access point, D-Link 5 ports Gigabit Switch, and connect the cable from the users to the router directly. Still, it didn't help.

    Thank you. I will give it a try.

    For a better diagnosis, I have got some output from tcpdump running on tomato, for which can be viewed on Ethereal or Wireshark. Though, I don't know exactly what to look for. :redface:
  11. Mercjoe

    Mercjoe Network Guru Member

    This is strange, I have recently (as in the last 2 days) started to get the LCP disconnect warnings in the logs. I have had absolutely trouble free PPPoE for over 4 years and I have been using Tomato since .4 (or so) and have started having these random disconnects suddenly with this in the logs.

  12. mike91k

    mike91k Addicted to LI Member

    Here's an interesting information: I monitored the router by opening up three command prompt sessions. On the first one, I let it ping to router's IP continuously. Second one to the ISP's DNS server. Third one to the IP address of the access point.

    I noticed that before the disconnection was going to occur, the ping results on the router's IP and ISP's are timed out. The one with access point is all okay. This means that the router hangs for some reason then disconnects the connection.

    So something is causing the router to freeze. Suggestions are welcome :biggrin:
  13. Planiwa

    Planiwa Network Guru Member

    Last Time:

    /var/log/messages.0:Jan 20 00:16:38 ROUTER daemon.warn pppoe[77]: LCP appears to be disconnected (pending: 5).
    /var/log/messages.0:Jan 20 00:16:38 ROUTER pppoe[77]: Sending LCP Termination-Request
    /var/log/messages.0:Jan 20 00:16:41 ROUTER pppoe[77]: Sending LCP Termination-Request
    /var/log/messages.0:Jan 20 00:16:44 ROUTER pppoe[77]: Connection terminated.
    /var/log/messages.0:Jan 20 00:16:44 ROUTER daemon.notice pppoe[77]: Disconnected.
    /var/log/messages.0:Jan 20 00:16:44 ROUTER daemon.notice pppoe[77]: Connect time 105.0 minutes.
    /var/log/messages.0:Jan 20 00:16:44 ROUTER daemon.notice pppoe[77]: Sent 18237225 bytes, received 118953986 bytes.
    /var/log/messages.0:Jan 20 00:16:44 ROUTER pppoe[77]: Sending PADT.
    /var/log/messages.0:Jan 20 00:16:50 ROUTER pppoe[77]: Exiting
    /var/log/messages.0:Jan 20 00:16:50 ROUTER pppoe[5840]: Starting
    /var/log/messages.0:Jan 20 00:16:50 ROUTER pppoe[5840]: Sending PADI.
    This time:

    /var/log/messages:Jan 23 01:35:21 ROUTER daemon.warn pppoe[5878]: LCP appears to be disconnected (pending: 5).
    /var/log/messages:Jan 23 01:35:21 ROUTER pppoe[5878]: Sending LCP Termination-Request
    /var/log/messages:Jan 23 01:35:24 ROUTER pppoe[5878]: Sending LCP Termination-Request
    /var/log/messages:Jan 23 01:35:26 ROUTER pppoe[11988]: Starting
    /var/log/messages:Jan 23 01:35:26 ROUTER pppoe[11988]: Sending PADI.
  14. nothize

    nothize Serious Server Member

    Combing with #11, would this be caused by some sort of network attack(eg. SYN FLOOD) that used up some memory/bandwidth and under low memory condition PPPOECD failed to work correctly?

  15. M0g13r

    M0g13r LI Guru Member

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