Interesting Problem

Discussion in 'Tarifa Firmware' started by Outer Marker, Jul 27, 2008.

  1. Outer Marker

    Outer Marker Guest

    I am using Tarifa version 32. Two weeks ago my ISP switched me from PPPoE to DHCP configuration. When I was on PPPoE configuration, I had my WRT54G do the PPPoE authentication for me... I had no software installed on my PC for PPPoE. Now I have confugured the WRT54G for DHCP since my ISP no longer supports the old way. I did a complete reset of the WRT54G to delete nvram of any old settings. Then I set it up with Tarifa 32 and DHCP.

    The problem is, every 3rd day, the router is no longer able to connect to the Internet. When I look at the status page, I see that the router is disconnected. I use the buttons on the router status page to renew DHCP... nothing, all zeros. If I reboot the router, it all works again!

    I asked my ISP what is special about 3 days, and they say that their DHCP leases are set for three days under DHCP config. Is this a bug in Tarifa 32? I wanted to downgrade to Tarifa 31 to see if the issue goes away, but can you tell me how to safely flash the router with 31? Can I just flash with 31, or do I need to do a hard reset of the router?

    Thanks in advance!

    -- Outer Marker
  2. jchuit

    jchuit Network Guru Member

    This is indeed an interesting problem, but to get more info you need to enable syslogd. If this is enabled the router will make a log file in tmp/var/log/messages. This log file can be opened with telnet (first enable it on the router).

    I must say, that I did see this problem before. Maybe it is some kind of bug in udhcpc, this udhcpd(c) package is very old and very difficult to debug.
    A newer package is available in Busybox (UDHCPD 0.9.9), but to inplement this a lot has to be changed and tested. (Maybe this is the way to go....)

    All Tarifa version do use the same UDHCPD package (0.9.8+broadcom patched+static leases).

    Restarting processes is originaly done by the KillAll program, if you hit DHCP renew the client should get a new ip adress, but the program isn't killed and the same for DHCP release.
  3. Outer Marker

    Outer Marker Guest

    Thank you very much for your prompt reply. I will turn on syslog this evening to see if any more information can be gathered for this issue.

    If UDHCPD 0.9.9 is the way to go, I would be happy to assist you in testing. However, if we need to implement a workaround for the future, I was thinking of a script to automatically reboot the router at night, every couple days. What would such a script look like, and where would I enter it? In the startup script section is my guess, but I am not sure of the syntax.

    Thanks for your excellent support of such an elegant firmware.
  4. Outer Marker

    Outer Marker Guest

    I think I found the answer to this problem. When I was using PPPoE, my router MTU was set to 1492. When I was switched to DHCP by my ISP, I used "Auto" which defaults to 1500. Today my Internet connection again dropped.

    Just for fun, I changed my router MTU back to 1492. I didn't even have to reboot the router, things just started working again right after I saved the new MTU value. After some further Internet research, some users are suggesting a lower MTU value is best for DHCP.
  5. jchuit

    jchuit Network Guru Member

    Improved renew and release.

    One cause could be, that is some situations a SIGUSR1 followed by a SIGTERM, the udhcpd and udhcpc process crashes.
    This could happen after a release and renew of the ip adress.

    Now in Tarifa 033 udhcpc and udhcpd services are stopped by a script, that kills the process by Process ID.
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