| Page Properties | ||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
...
Solution: Allow the setting of an IP address that will be used to modify the SIP headers, such as From and Contact, as well as the SDP headers defining the RTP connection information to the external IP of the EC2 instance.
The SR140 needs to be aware of the NAT device's public IP address. This public IP address will be used in place of the private IP address. This setting can be a single value for the whole system assigned when SR140 starts (in configuration file).
Assumptions
Requirements
| # | Title | User Story | Importance | Notes |
|---|---|---|---|---|
| 1 |
...
Below is a list of questions to be addressed as a result of this requirements document:
| Question | Outcome |
|---|---|
| No. There will be two new keywords. nat_sip_address and nat_media_address in the callctrl.cfg file. |
2. Who will obtaining the public IP address? Is it the responsibility ofthe customer or is the SR140 required to figure out what external IP of the system is? | The customer will obtain the public IP addresses for SIP and Media and enter them under the keywords nat_sip_address and nat_media_address, respectively. |
| 3. If there is a new keyword for the public IP address in the callctrl.cfg file, will this keyword take precendence over the other keywords such as sip_Contact, sip_ip_interface and sip_From? | The two NAT keywords in the callctrl.cfg file will take precedence over the other keywords such as sip_From, sip_Contact, etc. |
| 4. What about the Request URI and the To: header fields? Will these use the public IP address? | These should use the IP address of the remote side which is receiving the fax. |
| 5. Support for both IPv4 and IPv6 or just IPv4? | IPv4 only. |
| 6. What about the port for the public IP address? | Leave the ports alone. The ports for the public IP addresses will be the same as the ports for for the private IP addresses. From HMP: Each private port number will be mapped to the same public port number on the NAT device The UDP and TCP ports in SIP and SDP won't be translated since the NAT device will be configured for matching private / public ports. |
| 7. |
2.
3.
4.
5.
6| What about incoming SIP messages. | Incoming SIP messages can be left as is. When sending from the AWS machine to my laptop, the SR140 recognizes and processes From HMP: Media server inbound SIP and SDP
Inbound SIP and SDP don't have private IP address issues at the media server
since the source transport addresses in SIP messages and SDP payloads are set
to the endpoint's public transport address.
The NAT device handles forwarding of the inbound IP datagrams to the media
server's private address. |
| 8. The HMP implementation only translates the From: Via: and Contact: fields for requests? What about the Contact: field in reponses. | This has now been changed as part of the check in for revision 4680. |
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-instance-addressing.html
http://bot.whatismyipaddress.com/