Solved V20 WebClient not working in local network

[gvsoft]

Hello and greetings,

We have upgraded to hosted V20 (Update 8) and setup the split DNS for the FQDN and everything is working fine OUTSIDE our local lan.
The problem is in the local network where we are getting the below message.



Our FQDN resolves to the server IP correctly and can ping both FQDN and server ip.

The web client only works through the internal server ip. What else is needed to be done? I cant figure it out.

 

[Alphabetic]

If you cant access 3CX via the FQDN internally, you must have a routing issue.

Whats the network topology? Are you doing something like NAT hairpinning?

does FQDN inside the domain resolve to internal IP?

 

[Kevin Attard Compagno]

If your FQDN to reach the web client from OUTSIDE the lan is https://example.com...

...then you MUST be able to use the exact same URL to reach it from INSIDE the LAN.

If not, then your split-DNS setup (particularly the local part) is suspect.

@gvsoft & @Alphabetic - if the internal DNS is resolving correctly, then NAT hairpinning should not even be involved in this context.

 

[Alphabetic]

If your FQDN to reach the web client from OUTSIDE the lan is https://example.com...

...then you MUST be able to use the exact same URL to reach it from INSIDE the LAN.

If not, then your split-DNS setup (particularly the local part) is suspect.

@gvsoft & @Alphabetic - if the internal DNS is resolving correctly, then NAT hairpinning should not even be involved in this context.

I've seen this exact issue happen when split DNS was set up on an older Draytek. The ping was returning the correct IP but the router just could not determine that the request was to be handled internally. Syslog showed it was trying to go out and in, and this router wasnt having it.

 

[Kevin Attard Compagno]

@Alphabetic - I understand the case, and I have seen it myself. If we wanted to be REALLY pedantic, that, technically is not a "hairpinning" issue per se, but a "get a router that does not have such silly routing bugs" issue. I am hoping that @gvsoft is NOT using a router from yesteryear.

 

[gvsoft]

@Alphabetic - I understand the case, and I have seen it myself. If we wanted to be REALLY pedantic, that, technically is not a "hairpinning" issue per se, but a "get a router that does not have such silly routing bugs" issue. I am hoping that @gvsoft is NOT using a router from yesteryear.

We are using a Zyxell USG FLEX 500

 

[gvsoft]

does FQDN inside the domain resolve to internal IP?

No it resolves to the external ip.

 

[Alphabetic]

No it resolves to the external ip.

This isnt split DNS.

Where is your DNS server?

 

[Alphabetic]

@Alphabetic - I understand the case, and I have seen it myself. If we wanted to be REALLY pedantic, that, technically is not a "hairpinning" issue per se, but a "get a router that does not have such silly routing bugs" issue. I am hoping that @gvsoft is NOT using a router from yesteryear.

It was an old router tbf, just took some time to come to this conclusion.

 

[gvsoft]

Ok, so I had made the split DNS on the 3cx server and not the "proper" server. So after the split dns is working and Alphabetic thank you because you helped me figure out the mistake with your question.

 

[Alphabetic]

No worries, its what we're here for