[asterisk-users] Voice broken during calls (again...)

[Marek Greško]

Hello,

this is a correct response:

>From 62.156.246.57 (62.156.246.57) icmp_seq=1 Frag needed and DF set
(mtu = 1492)

So PMTU discovery is working. No problem here. You got correct message
to lower the packet size from 62.156.246.57. This is probably the last
hop before your site.

Marek



2020-06-23 9:40 GMT+02:00, Luca Bertoncello <lucabert at lucabert.de>:
> Am 23.06.2020 09:28, schrieb Marek Greško:
>
> Hi
>
>> if you need clampmss then it is highly probable there is a PMTU
>> discovery problem. The clampmss does not work for UDP.
>
> Is there a way to check if I have this problem?
>
>> I probably counted the size incorrectly. So you are able to ping with
>> size 1464 and not with 1466. How about trying same ping sizes from the
>> internet towards your site? I mean trying to ping from sites with
>> higher MTU than yours without lower MTU links in the path.
>
> lucabert at ns:~$ ping -4 -M  do -s 1465 bpi.d.lucabert.com
> PING bpi.d.lucabert.com (93.241.91.232) 1465(1493) bytes of data.
>  From 62.156.246.57 (62.156.246.57) icmp_seq=1 Frag needed and DF set
> (mtu = 1492)
> ping: local error: Message too long, mtu=1492
> ping: local error: Message too long, mtu=1492
> ping: local error: Message too long, mtu=1492
> ^C
> --- bpi.d.lucabert.com ping statistics ---
> 4 packets transmitted, 0 received, +4 errors, 100% packet loss, time
> 3965ms
> pipe 2
>
> With paket size of 1464 it works...
>
>> You know MTU is a size of l2 frame, so using ipv6 you are able to use
>> higher payload sizes because of ip header size.
>
> OK, thanks!
> Luca Bertoncello
> (lucabert at lucabert.de)
>
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