Presence for 3CX soft client using FQDN

[DARSFoG]

Long story short I have a very complicated network hosted firewall that is keeping presence from working.

3CX system
Internal IP: 192.168.1.7
External IP : xxx.xxx.xx1.228

Test System:
Internal IP: 192.168.1.224
External IPL xxx.xxx.xx1.224

Anything outside of the network can get presence. It's only machines/clients internally that can't. I can make calls from the soft-client just fine. Wireshark confirms that presences is trying to use the FQDN instead of the local IP of the 3CX system.

Is there anyway to change this behavior? I've never had this issue, but at the same time I've never had to deal with a very complicated hosted firewall.

Thoughts?

 

[Sopock]

Wireshark confirms that presences is trying to use the FQDN instead of the local IP of the 3CX system.

And in that complicated network there is no local DNS which should resolve it to 192.168.1.7?

 

[craigreilly]

Basically setup the FQDN on the internal DNS?
If you do not have an internal DNS server - then you need to reconfigure 3cx.

 

[DARSFoG]

There is an internal DNS and does have the FQDN resolving to the internal IP.

Here is the kicker that I should have included.

Nmap scan of local IP shows all required ports open.
Nmap scan of FQDN does not show required ports open.
Nmap scan of FQDN from outside network shows required ports open.

 

[Sopock]

yes, now situation is clear:
Why can't I access forwarded ports on my WAN IP from my LAN/OPTx networks

 

[craigreilly]

Nmap scan of FQDN does not show required ports open.

My guess is that NMAP is not using internal DNS server to resolve name of FQDN to internal IP. I haven't used it... but ut seems that is the case based on the 3 behaviors you state.

 

[Sopock]

From this example we can see how important is to have a mobile workstation/server powered by ESXi as drop-in replacement for DNS or even SG-1000?

 

[craigreilly]

Why do we need an ESXi powered machine?

 

[Sopock]

Only for convenience? It should be quickest way to confirm by simply starting pfSense appliance?

Is there anyway to change this behavior?

It's unlikely that 3CX softphone will change it?

 

[DARSFoG]

Just an update. I ended up backing up the config and reinstalling 3CX and it seemed to solve the issue. So... I have no idea.