How is my PPPoE DSL link coming back after it fails?



  • Shortly before 10am my PPPoE DSL connection died.

    The first mention of it in the log is about 5 minutes later:

    
    Oct 19 10:03:01   check_reload_status: rc.newwanip starting
    Oct 19 10:03:03   php: : Informational: rc.newwanip is starting .
    Oct 19 10:03:03   php: : rc.newwanip working with (IP address: 216.8.131.217) (interface: wan) (interface real: xl0).
    Oct 19 10:03:08   php: : Informational: DHClient spawned /etc/rc.newwanip and the new ip is wan - 216.8.131.217.
    Oct 19 10:03:08   php: : Creating rrd update script
    Oct 19 10:03:08   php: : pfSense package system has detected an ip change 216.8.131.235 -> 216.8.131.217 ... Restarting packages. 
    

    What i don't understand is that the first pfSense realizes there is a problem is when something detected a new ip. i thought that when using PPPoE DSL, the router itself requests an IP from the ISP's DHCP server. If that were the case then i would see some log activity from the router saying how it would be initiating a PPPoE connection, logging in, getting an ip, the new ip it got, etc.

    So my DSL modem must have lost connection shortly before 10am. i assume the modem kept trying to reconnect, and after 5 minutes of retries it was finally able to re-establish a connection over the phone lines to the ISP. Does this mean that when my modem connects, my ISP is assigning me an IP? And if the IP is assigned to me when my modem connects, but before my router "dials" the PPPoE connection, does that mean that the PPPoE protocol allows for the calling router to be told what IP it has been operating on since the modem connected?

    Additionally, how does pfSense finally realize that the connection had a problem? Is it only because check_reload_status watchdog process detected an IP change? How is check_reload_status detecting an IP change when the router itself didn't change the IP? Is check_reload_status connecting to some checkmyip.org type service that you guys are running and seeing that the IP has changed - which then triggers a PPPoE reconnect?

    What would happen if when my modem reconnected, the ISP happened to gave me the same IP. Would pfSense never realize that it needed to reconnect using PPPoE because check_reload_status never saw a new ip; and i'd be stuck offline until i manually initiated a disconnect/reconnect?

    Put it another way: how is my PPPoE DSL link coming back after it "fails"?


  • LAYER 8 Moderator

    I assume you're running the WAN Interface in PPPoE Dialup Mode as you're talking about a DSL Modem in front of pfSense and some other router?
    So I also assume the answer you're looking for is quite simple. As your connection failed, pfSense recognized that on the WAN IF as the established PPPoE connection via you modem didn't exist any longer. So if you enabled "Dial on Demand Mode" on the WAN side (Interfaces, WAN) and set an idle-timeout of 0sec, pfSense is trying to re-establish the PPPoE link on demand (e.g. if some packets should be sent).
    After logging in is successful the WAN IF receives its new IP adress from the provider. The modem itself has IMHO (speak: only german DSL background) no capability to do any layer 3 activity itself (e.g. receiving IP adress from provider and hand out to pfSense).

    I have a lot of "mpd: ..:" messages after a DSL dis- and reconnect in the system log, telling me the PPPoE daemon has reestablished connection and gained new IP adresses (and DNS servers).

    HTH
    Greets Grey



  • Jack,

    would you mind inserting your text as 'code' as opposed to 'table'
    This seems to render it in an annoying white on light grey which is pretty heavy to read.
    Highlighting your posts to be able to read it is sub optimally…

    I'm going to contact the admins and see if they can change the style sheet or whatever causes this to a readable version.



  • @Grey:

    I assume you're running the WAN Interface in PPPoE Dialup Mode as you're talking about a DSL Modem in front of pfSense and some other router?

    There is no other router. My modem is plugged into the WAN network card of the pfSense machine. pfSense is not in Dial on Demand mode.

    As your connection failed, pfSense recognized that on the WAN IF as the established PPPoE connection via you modem didn't exist any longer.

    How does pfSense recognize that the PPPoE connection doesn't exist anymore? Does it log any of this activity? Does it log trying to reconnet using PPPoE?

    I have a lot of "mpd: ..:" messages after a DSL dis- and reconnect in the system log, telling me the PPPoE daemon has reestablished connection and gained new IP adresses (and DNS servers).

    i get no such messages, as you saw in the log. The first mention in the log of a new connection is a new WAN ip being detected.



  • @jahonix:

    Jack,

    would you mind inserting your text as 'code' as opposed to 'table'
    This seems to render it in an annoying white on light grey which is pretty heavy to read.
    Highlighting your posts to be able to read it is sub optimally…

    I'm going to contact the admins and see if they can change the style sheet or whatever causes this to a readable version.

    On my screen tables look no different than any other text, except that it's all aligned into cells (there's not even any table or cell borders). i've not fiddled with any stylesheets or color preferences - if any even exist.

    i was weary of using a code block, since it won't wrap nicely - but i can go back and edit it all the same.



  • Not that it's really important, here's a screen capture from: http://forum.pfsense.org/index.php/topic,6532.msg37521.html#msg37521

    ![pfSense forum table colour.png](/public/imported_attachments/1/pfSense forum table colour.png)
    ![pfSense forum table colour.png_thumb](/public/imported_attachments/1/pfSense forum table colour.png_thumb)


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