Unable to register SIP via WiFi

Question

We run a FreePBX server on our LAN and softphones can register using the local SIP server IP.

I need these softphones to be able to register over the internet too so we have configured the firewall and created a dns entry for sip.ourdomain.com.

When the softphones are configured to use sip.ourdomain.com then can register over the internet fine however when they are in the office and are connected to the wifi they are unable to register.

I suspect this is because when in the office they are trying to register to sip.ourdomain.com which resolves to the public IP that redirects to the sip server on the local LAN.

How can this be resolved?

Edit1

LAN is 192.168.1.X/24 & SIP Server is 192.168.1.8

does your SIP server has an internal private IP address? I see you tagged nat — Rui F Ribeiro, May 09 '18 at 23:12
Yes, 192.168.1.8. Tagged NAT as from the WAN IP to internal IP — Dercni, May 09 '18 at 23:16
Bring up a simple DNS server on the LAN and resolve that IP on it. I do that on my Zeroshell router for example. — ajeh, May 10 '18 at 00:06

Rui F Ribeiro · Accepted Answer · 2018-05-10T07:20:43.533

2

What you may need is defining in your infra-structure a split view DNS or multiview DNS architecture.

Thus in your internal network, your internal DNS server will resolve sip.ourdomain.com to 192.168.1.8 and externally to the current public IP address.

Another alternative is enforcing a public IP address for the SIP server instead of a private IP address.

I usually advise network administrators using public IP addresses for SIP servers and VPN servers for not having to deal with some corner cases of NAT problems.

edited May 10 '18 at 07:20

answered May 09 '18 at 23:18

Rui F Ribeiro

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Thanks created an A record on the LAN DNS server that points sip.ourdomain.com to 192.168.1.8 – Dercni May 10 '18 at 01:42

Unable to register SIP via WiFi

1 Answers1