Hi Henning,
I browsed the files but was unable to find one using Kamailio as SBC
without exposing the Asterisk core.
Most examples indeed expose the node and let media flow directly (
Day1/08-David.Casem-Building-A-Global-VoIP-Network.pdf - interesting
solution with e/iBGP which we would also be able to deploy).
There was just a single presentation that I was able to locate that had
the proxy only on the edge:
Day2/15-Sebasitan.Damm-Anti-Fraud-With-HTables.pdf
At least it looks like they are located behind the SBC.
After the research my impression is, that co-locating the B2BUA with the
Edge-Proxy and firewall-ing it, seems best practice.
We will try to add some security by bridge-firewalling and BGP.
If anyone has a hint for a presentation with high-security edge-proxy, I
would appreciate it. Thank you.
Kind regards,
Kevin
Am Do., 16. Aug. 2018 um 19:12 Uhr schrieb Henning Westerholt <
hw(a)kamailio.org>gt;:
Am Donnerstag, 16. August 2018, 11:57:03 CEST
schrieb Kevin Olbrich:
I am working successfully with Kamailio in my lab
setup where Kamailio
is
the SBC for Asterisk.
The network layout is looking like this:
SIP-Phone <== PUBLIC NET ==> Kamailio (SBC) <== PRIVATE NET ==>
Asterisk
<== PUBLIC NET ==> Carrier
Each public network is reachable from the internet and has a local
firewall
with IP whitelists.
The internal SIP transactions are UDP-only but for external phones I
would
like to also listen for TCP/TLS.
For this layout to work with rtpproxy (before we move on to
RTPengine), we
have to enable mhomed in Kamailio.
We also have some routing issues with packets leaving with the wrong
IP via
rtpproxy (when call between carrier and external
phone needs to be
bridged).
Most examples show that Asterisk is deployed on the same network as the
external interface of Kamailio (-> Asterisk exposed to the public
network).
In our tests, this works much better but I have
great security concerns
because this Asterisk instance itself does not need to be reachable
from
external.
How do other users deploy Kamailio in front of Asterisk or similar as
SBC
to secure internals?
There is lot of docs for Kamailio's config but IMHO less for the setup
as
DMZ (SBC) proxy.
Hello Kevin,
this is indeed a common setup to protect asterisk and to have also much
greater flexibility with regards to balancing and/or SIP message
adaptions.
To get some ideas, have a look to the last years conferences available
here:
https://www.kamailio.org/events/
There should be some talks about using Kamailio to in front of asterisk,
the
talk name is usually in the file name.
I think even on this year cluecon Fred Posner did a talk about Kamailio
as
Edge Proxy, and also on astricon there were some talks about this
scenario if
I remember correctly.
You should also find in the Kamailio World or FOSDEM talks a lot of
information about this scenario. You find all the talks available from
Kamailio World in our youtube channel:
https://www.youtube.com/kamailioworld
Best regards,
Henning
--
Henning Westerholt
https://skalatan.de/blog/
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