Could my router firewall be stopping a SIP connection?

Installing and Using OpenWrt
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With Skype being deceased and having run out of credits I have been trying to find a low cost provider to call landlines abroad from my windows laptop. I have tried several web based applications which have failed miserably and have today been trying to set up Zoiper, 3CX and MicroSip soft phones with LocalPhone as the Internet phone provider (their description…).

When I initiate a call all 3 fail to connect which may well be issues with the Localphone access however I thought I would ask if there is a setting in the firewall which may impact this?

If you need set up please let me know but will likely be tomorrow before I reply. Thanks in advance if anyone can shed some light.

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Have you opened the firewall for the audio streams?

Fail to connect - or no audio?

Or doesn't register?

(The SIP logs from both ends would clearly explain.)

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Not that I am aware of. How would I do that?

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Sorry if you mean the access to those programs on my windows firewall then yes. I thought you were referring to Openwrt firewall.

5

I use Localphone and have not noticed any problems. There’s no special configuration required on Openwrt. Just make sure that the SIP ALG helper isnt installed (it isnt by default)

As asked previously, is it failing to register ? or failing to make the call ?

do you have credit on the localphone account

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I was refering to the OpernWrt firewall.

You didn't mention that the soft phone was on Windows, but yes, audio must be able to pass thru all firewalls.

But I would follow this user's advise instead - as they use the same service and say that no [special] configuration is required. I am speaking of SIP in general.

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Thanks. Can you tell me what Soft Phone you are using with them? Their own Internet phone download is no longer available as apparently it doesn’t work anymore due to Windows code changes - which I am struggling to understand but that’s what they told me and then recommended the 3 I am trying.

I have literally just tried to make some calls. Connected fine to local Thai mobile numbers but would not connect to UK fixed or mobile which is what I need it for.

Logs for 2 say code 503 no route and one states “server too slow, network unreachable”

Yes I have credit which I only added once I had the supposedly confirmed set up details……

8

Softphones are typically bad, as the phone's normal power saving mechanisms tend to kill the apps.

Many SIP phones or pbx have a configurable setting to regularly SIP-ping the SIP server and thereby keep the SIP session active and the teach the router's firewall (conntrack table) to allow incoming SIP connections. If yours does, this is a proven and elegant approach that 'just works'. If your chosen devices don't, you need to set up these port forwardings (or traffic rules for IPv6) by hand. Both approaches work, but the former is preferable.

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Thanks for responding.

Turns out it was nothing to do with any firewalls.

The issue was that in one of localphone’s settings Caller ID was hidden (I don’t recall changing it but who knows). Changing that and a test call with one of the 3 went through first time.

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Ah! by default the caller ID presented by Localphone will be the 6 digit account number. You can register additional phone numbers to be used as CID, providing you can demonstrate you ‘own’ them. You can then select which of those is presented as the CID.

I dont routinely use a softphone, I have a Gigaset N300 IP DECT system, but do occoasionally use Zoiper when I’m away from home.

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