CDMA: PPP connection restart on unexpeted peer LCP reconfiguration request

Vladimir Dvorak dvorakv na vdsoft.org
Neděle Květen 29 18:56:16 CEST 2005


Tomas Sieger wrote:

>Hi,
>   I'm experiencing problems with my Eurotel CDMA modem.
>
>   I can successfully establish a PPP connection, but it gets
>shut down and restarted after a while. It seems that the
>reason is the peer (Eurotel) has sent an LCP request for
>reconfiguration, which causes ip-down to be started etc.
>   The time delay between connection establishment and
>shutdown varies from 2 seconds to several hours. It seems
>this delay depends on the time of day - on working days it
>is quite often - in order of minutes or tens of minutes,
>while in evenings and on weekends it takes much more time
>to experience it. Perhaps the network load is the key?
>
>I'm using wvdial 1.54.0 / pppd 2.4.2 on FC 3, kernel 2.6.9,
>Intel platform.
>
>Note: when I just set up the PPP connection, but do not actively use it
>(using default route via eth0), the problem does not appear.
>
>Please, take a look at the snippet of /var/log/messages attached.
>
>thanks in advance for any help
>best regards,
>   Tomas S.
>
>PS: I'm writing in English to ease other people to google
>help using English terms ;-).
>
>  
>
Tak nevim, zda mam psat anglicky v ceske konferenci; doufam, ze si
porozumime (nejen po jazykove strance ).

Rad se s vami podelim o svou zkusenost s restartovanim tohoto velice
"kvalitniho" pripojeni. Mam doma malou sit, ktera je pripojena pres
maskaradu do Internetu. NAT resi muj linuxovy pocitac, za nim pak je
heterogenni sit (XP, FreeBSD, W98). Pokud z nejakeho duvodu spojeni na
routeru prerusim a znovunahodim, rozebehne se po kratke dobe zajimavy
cyklus restartovani pripojeni, ktery trva a trva.
Behem analyzy jsem si uvedomil, ze vlastne za NATem jsou stanice, ktere
maji jiz sestavene nejake TCP spojeni a tudiz se snazi do Internetu
propasovat sve treba keep-alive pakety. Tyto ovsem muj NAT neprelozi
(protoze po nove nastartovanem spojeni dostal jinou IP adresu a nezna
pro tuto IP stavy ) a posle je eurotelackemu routeru se zdrojovou
adresou me vnitrni site. To se ET nelibi a posle mi "LCP reconfiguration
request". Ty stanice o teto situaci nevedi, ktera se deje mezi mym
firewallem a Eurotelem, a vesele dorazeji ACKy do Internetu. A toto je
duvod toho loopu restarovani pripojeni.
Muj workaround je takovy, ze vymazu ip_conntrack stavovou tabulku.

Pokud je to i Vas pripad, doufam, ze jsem pomohl.

 Vladimir Dvorak




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