Solved IP range for 3CX hosted SMTP servers

[Wendell Urth]

Hi there,

I am hosting / trialling a 3CX standard server (free version at moment) on Windows 2016 and understand that the email is routed via a 3CX owner SMTP server. I will be using this to send voice mail attachments, and to one domain only.

My own, internally hosted email services, are protected by firewall, IDS etc. I would like to know the IP address ranges from where the 3CX SMTP traffic will originate if that is at all possible please? I'll then be able to white list this traffic so that email is delivered correctly.

Note: I fully intend to purchase a licenced version but am testing all the required functionality before committing.

Thanks again for your help,
W

 

[YiannisH_3CX]

Hello @Wendell Urth

You can get the IPs by performing an nslookup to the following address: smtp-proxy.3cx.net
Please note that the IPs are subject to change so if you can create a rule based on the FQDN i would recommend doing so.

 

[Wendell Urth]

Many thanks YiannisH, that's perfect and i'll only need for the duration of my testing so should satisfy my needs.

Have a good weekend,
W

 

[YiannisH_3CX]

Glad i could help. Have a good weekend also

 

[RodSlinger]

Thanks!!!! That just helped me out also. I sent an email about this but of course didn't get the response due to the inbound IP block.