Re: PPPoE Modem hangup after random time - how to debug?

Michael Richardson
2020-04-26T01:38:35Z

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David Balažic <xerces9@gmail.com> wrote:
>> OK, more data:
>> I started tcpdump with the -e option as suggested on openwrt forum:
>> tcpdump -e -v -i eth1.3902 pppoed
>>
>> on disconnect, this was logged (times are UTC):
>>
>>
>> tcpdump: listening on eth1.3902, link-type EN10MB (Ethernet), capture
>> size 262144 bytes
>> 18:23:09.204991 a4:7b:2c:9e:c7:44 (oui Unknown) > 44:4e:6d:fd:c7:39
>> (oui Unknown), ethertype PPPoE D (0x8863), length 97: PPPoE PADO
>> [Service-Name] [AC-Name "SIMB_TABOR_BNG1"] [Host-Uniq
>> 0x44************long_number******************************AA]
>> [AC-Cookie ".5b************v"]

> Isnt this strange? The dst addr is not my router or any other known.
> Also the Host-Uniq value is different.
> As if is traffic meant for someone else.

oh, I understand.
thank you for noting this.
So, it's as if you are getting a PPPoE message for someone else, and when
that happens, the interface is dying.
Is it always the same ethernet address?

Do you have ebtables? Could you arrange to filter out packets like that?
That would point to there being some kernel bug.

Clearly, your ISP has some other bug that they are sending stuff down the
wrong pipe, but that could just be hash collisions that they assume are
"harmless".

--
] Never tell me the odds! | ipv6 mesh networks [
] Michael Richardson, Sandelman Software Works | IoT architect [
] mcr@sandelman.ca http://www.sandelman.ca/ | ruby on rails [

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