public IP of the 3CX server

[A-CBurr]

We setup a new ISP connection
Server is egressing out a new Public IP - have all inbounds good but the dynamic inbound xxxx.ca.3cx.us isn't updating.
switched to dynamic (dashboard shows new IP) but the dynamic never updated 24 hours later
turned off the inbound - and naturally causes issues - but can't figure out why its not updating..

changed back to static IP the new public IP for external - still no update to the dynamic... maybe get a new one I guess?

 

[Marconi]

How did you check that the FQDN hadn't updated? It may be that the DNS server you queried had a stale entry and wasn't showing the correct information. I would suggest you change the IP for the FQDN as required and, after giving DNS a decent time to update, run the following commands (they work on both Windows and Linux) from a command prompt (shell):

nslookup xxxx.ca.3cx.us 1.1.1.1
nslookup xxxx.ca.3cx.us 8.8.8.8
nslookup xxxx.ca.3cx.us 9.9.9.9

They will query the IP from the Cloudflare (1.1.1.1), Google (8.8.8.8) and Quad9 (9.9.9.9) DNS servers directly. If they are showing the correct (i.e.: new) IP address for the FQDN then you have a stale DNS cache at your end.

On Windows you can clear the DNS cache for a computer using the command ipconfig /flushdns in an Administrator command prompt. If you run the command on a Windows Server providing DNS then it will clear the cache and anyone connecting to it will get the updated information.

 

[Saqqara]

What version of 3cx are you running ?

 

[A-CBurr]

fair questions -
remote - using cloudflare - and doing flush and checking from other networks not using cflare -

on server itself 3cx debian - 18.0 Update 5 (Build 418)Version
dig +short txt ch whoami.cloudflare @1.0.0.1 - gives correct IP new static

nslookup xxxx.ca.3cx.us 9.9.9.9
nslookup xxxx.ca.3cx.us 1.1.1.1
both showing old IP

not updating the record from 3cx dynamic dns side

 

[A-CBurr]

so something in this thread is similar -
https://www.3cx.com/community/threads/fqdn-update-dynamic-ip-mechanism.60492/

enabling ping reply on that interface to see if that work...
currently my custom domain works fine... thinking of switching it but would require a backup and reload of config to resolve that name as the correct name...

voice.domain.com which is tied to CF so I could update on the next IP change as well easier / faster... but i'm fine with the dynamic name for now.
next Ip change could be within 45 days ---

----
Change off of Fiber > Cable mainly for practice while both connections are active
Move office > New Cable
maybe later get back to Fiber but fine for now with Cable less upload but better down and better price for a bit - let corp recover from move expenses for year or so!
---

 

[Marconi]

If you haven't already done so, I would suggest disabling "Automatically Bind to IPv6 Adapters" as this can cause problems with some systems. Remember to restart the "3CX PhoneSystem 01 SIP Server" service for this change to be applied (or just restart the 3CX server).

 

[A-CBurr]

that's been disabled for quite a awhile but always good to recheck and cycle it again
no change

I even temporarily disabled the other WAN interface just to see if that helps - Nope No change
one thing I also noticed - Server using internal DNS
not major execpt xxx.ca.3cx.us domain I have a zone in there that replies with internal -
so in the event this happens - internal clients softphones still work even if the external dns gets messed up like it is now.
call path stays internal - vs going out and back in again.

I changed dns to public and allowed the 3cx server outbound to public dns - still didn't update the dynamic domain.

dashboard currently showing correct wan IP when in dynamic Mode but not updating the darn dynamic domain
plan on having 3cx check and see if I have something else fouled up...

I just need to see the dynamic updater script and see what I can find if that log if it exists.

 

[Marconi]

OK, you've just mentioned a couple of interesting points that I'd like to clarify:

1) Does you 3CX server have more than 1 network card?
If it does, this could be causing some of the problems. It is best (where possible) to have only 1 network card on the 3CX server as more than 1 can and, from my personal experience does, cause unusual and difficult to diagnose network issues. Although 3CX supports using more than 1 network card I know VoIP professionals (i.e. 3CX advanced certified with years of experience) who say don't do it.

2) Are you running an internal DNS server with a xxx.ca.3cx.us zone defined?
If you are (and I have done this successfully), did you make sure to change the IP address in your local DNS server when you changed it on the 3CX server (I made the mistake of not updating the IP on the local DNS server once and have the grey hair to show for it)?

 

[A-CBurr]

1) Does you 3CX server have more than 1 network card?
Just 1

2) Are you running an internal DNS server with a xxx.ca.3cx.us zone defined?
Yes - is the internal IP vs external IP - this allows all internal clients to never leave the network
--- also thought this could be an issue with the updater - but shouldn't be..
so I aimed DNS to a public dns and left it there for 36 hours - and still no update....

Will restart the Configuration Services Service this evening - but rebooting the server hasn't helped either so not sure it will do much
rebooted a couple times last week - no difference.

 

[Marconi]

It certainly sounds like you're doing everything right so I expect that the problem is with the DNS for the 3cx.us domain. Unfortunately that is out of your control so, hopefully, someone from 3CX is following this post and can take a look for you.

 

[A-CBurr]

last night restarted Configuration Server service and now appears to be registering the correct IP

I also had a PM to

YiannisH_3CX
it was his suggestion to restart that specific service - so looks like that got it!