asterisk users - Feb 2021 - Change by Deutsche Telekom end of februar. Can someone help me?

Am 15.02.2021 um 21:40 schrieb Michael Maier:

Hi Michael,
> They're switching to DNS NAPTR / SRV[1]. If you are using Asterisk /
> pjsip and hostnames (tel.t-online.de e.g. for the AllIP service), you
Mmm... I'm using tel.t-online.de, but I'm not sure I'm using
pjsip...

module show say me:

res_pjsip.so                   Basic SIP resource
46         Running              core

Do I use pjsip?
> won't have any problem (using asterisk 14 or higher), because it's
> default. But you may have problems with the handling of the calls,
> because Telekom needs the client always to use the same server for all
> activities after the register has been done (the SRV entries contain 3
> servers and asterisk will use them "randomly" if it detects a
problem -
> regardless which server of the list has been used for registration -
> this won't work with Telekom and will lead to not working outbound
calls
> / interrupted calls e.g.). This won't happen very often (because they
> have been extremely stable in the past), but I could see it nevertheless
> already. If you want to be really sure to not face this problem, you
> have to create a workaround by adding a rpz zone e.g. with an own bind,
> which is fed by an own job and presents asterisk just one server when
> looking up the SRV entries after the NAPTR call. NAPTR / SRV works like
> this (example for tel.t-online.de):
You mean, I have to create a "fake" Zone tel.t-online.de in my Bind
with
these settings? Looks like dangerous, if they changes something...

Thanks
Luca Bertoncello
(lucabert at lucabert.de)

Hi Luca,

On 15.02.21 at 21:48 Luca Bertoncello wrote:
> Am 15.02.2021 um 21:40 schrieb Michael Maier:
> 
> Hi Michael,
> 
>> They're switching to DNS NAPTR / SRV[1]. If you are using Asterisk
/
>> pjsip and hostnames (tel.t-online.de e.g. for the AllIP service), you
> 
> Mmm... I'm using tel.t-online.de, but I'm not sure I'm using
pjsip...
> 
> module show say me:
> 
> res_pjsip.so                   Basic SIP resource
> 46         Running              core
> 
> Do I use pjsip?
pjsip show registrations
> You mean, I have to create a "fake" Zone tel.t-online.de in my
Bind with
> these settings? Looks like dangerous, if they changes something...
If you do that statically -> yes, you're right. You have to do it
dynamically. I attached a script, which can be used to dynamically build
a rpz each 15 minutes e.g. It directly asks the telekom nameserver for
naptr and srv entries. It looks like this:

server 192.168.62.13
zone rpz-tonline
update delete tel.t-online.de.rpz-tonline.
update delete _sips._tcp.tel.t-online.de.rpz-tonline.
update delete _sip._tcp.tel.t-online.de.rpz-tonline.
update add tel.t-online.de.rpz-tonline. 60      NAPTR   10 0 "s"
"SIPS+D2T" "" _sips._tcp.tel.t-online.de.
update add tel.t-online.de.rpz-tonline. 60      NAPTR   30 0 "s"
"SIP+D2T" "" _sip._tcp.tel.t-online.de.
update add _sips._tcp.tel.t-online.de.rpz-tonline.      60 SRV  10 0
5061 s-eps-110.edns.t-ipnet.de.
update add _sip._tcp.tel.t-online.de.rpz-tonline.       60 SRV  10 0
5060 s-epp-110.edns.t-ipnet.de.
send

You have to configure bind to use the rpz for all lookup calls resolving
*.tel.t-online.de. I assume that the individual t-ipnet.de entries are
"statically" and therefore resolved directly (w/o rpz). But this could
be added to the script, too (would be a new rpz).

At the moment, I'm using only one DNS server for digging the NAPTR and
SRV entries - this could be enhanced to use 2 servers if the first
fails. If the first fails, the script currently stops and does nothing.
I assume, that the DNS server is stable.

The script unregisters and registers the telekom trunks, if a change is
detected. This is done as long as there is no call active. This works
for me - but may not wort for others - feel free to change the code.
Independently you have to add your own trunk names to get it working
(telekomPJSIP-a, ...).

You can verify if it's working by checking for entries like this in
journalctl:
Feb 16 19:35:46 myfw named[1516]: client @0x7ff574027bd0
192.168.62.13#25869 (tel.t-online.de): rpz QNAME NODATA rewrite
tel.t-online.de via tel.t-online.de.rpz-tonline
They are appearing at the moment asterisk starts a lookup.


Hope this helps!


Thanks
Michael
-------------- next part --------------
A non-text attachment was scrubbed...
Name: check-t-online.pl
Type: application/x-perl
Size: 5021 bytes
Desc: not available
URL:
<http://lists.digium.com/pipermail/asterisk-users/attachments/20210216/668328fd/attachment.bin>