[asterisk-users] IAX port

Ishfaq Malik ish at pack-net.co.uk
Tue Feb 10 07:04:24 CST 2015


On 10 February 2015 at 12:55, jg <webaccounts173 at jgoettgens.de> wrote:

>
>> Some firewalls have a 'consistent NAT' option that needs to be enabled,
>> otherwise you get the symptoms described.
>>
>>  While reading about NAT, I came across this web site:
> http://nattest.net.in.tum.de/
> The test tool looks at various NAT related properties and prints the
> results related to TCP/UDP binding properties, TCP/UDP hole punching, etc.
>
> In my case a very short value was reported for the UDP timeout, such that
> depending on the sequence of packets, the entry in the mapping table might
> already have been deleted. This could explain the random nature of my
> connection problem. Port predictability does not seem to be a problem.
>
> Does that make any sense?
>
> jg
>
>
Yes

UDP timeout being too short is another thing I've experience with firewalls
(admittedly limited and once removed experience). Actually, this one can be
a (mild) problem on Draytek routers and can be resolved by telnetting into
the router and using the portmaptime command.

Also, turn of stateful packet inspection if it is an option.


-- 

Ishfaq Malik
Department: VOIP Support
Company: Packnet Limited
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