Blocking Scanners Plus Questions.

[azrobert]

I have a DD-WRT router that has an option on Port Forwarding to limit the forwarding to a source IP address. I use the Oleg method to block scanners and it works perfectly, but this and other methods on the forum will let the scanner calls into your network and the OBi rejects them. If you include each of your provider's IP in a Port Forwarding entry the scanner calls are blocked at the router and never enter your network. No need to setup blocking in the OBi.

If your Provider uses SRV records you can get a list of the servers on a Windows machine like this:
Open a Command Prompt window.
Key the following:
nslookup
set type=srv
_sip._udp.callcentric.com

The _sip.udp. does not work for sip2sip, so do the following:
nslookup
ping proxy.sipthor.net

Negatives:
Not all routers have this option.
This might require more entries in your router.
If your provider changes IP, calls might fail.

Questions for any network guru.

Question 1
Why doesn't "_sip._udp.proxy.sipthor.net" work?
_sip._udp.callcentric.com produced 2 more servers than ping.
alpha14.callcentric.com and alpha16.callcentric.com
Why?

Question 2
I always thought Port Forwarding was not required for a registered provider. I tried turning Port Forwarding off and outbound calls worked perfectly, but inbound were inconsistent. Some rang, others didn't. Turning Port Forwarding back on fixed the problem. I don't know if another problem was happening at the same time. I did not try to reproduce the problem.
Is Port Forwarding required for registered providers?

Thanks
Twinkle Toes (Inside Joke)

[giqcass]

Port forwarding shouldn't be needed with registered services when everything is doing what it is supposed to do.  The only way for the router to know where to send traffic is if the ports are forwarded or if the device opens the port from the inside and say send this traffic to me.  Registration should open the ports but I can think of a couple of things that might be happening.

1)Perhaps registration time is too high.  The router might think the Obi is done with the port. 
2)Another device might have grabbed the port for itself.  If you used another sip program or device with the same port that could cause an issue.

[azrobert]

I have a 1 hour registration time. I didn't know that could cause a problem.

Thanks for the info.

[giqcass]

Mine are all set to 60 seconds. It was the default so I left it alone.