Hello, we have a sip server. SIP internal line has no problems. But unfortunately we couldn't get it to work on the outside line. A router was recommended for this. I don't know how to configure the router. I would like your support regarding this.
Firewall: Fortigate - Router: Cisco 2901
Please have a look at these documents and let us know any specific questions you might have after reading through them.
Cisco Unified Border Element Configuration Guide Through Cisco IOS XE 17.5
Explain Cisco IOS and IOS XE Call Routing
