09-12-2023 07:36 AM
Hello,
I have one issue regarding PAT. We are trying to register our local Phone server to ISP SIP server. On our local Phone Server we have private IP and the we do PAT for accessing to internet. And during this PAT I see that the source port of is changing. How I can disable source port changing during PAT?
Solved! Go to Solution.
09-12-2023 11:38 PM
I changed NAT configuration from interface to IP NAT Pool and right now source ports are the same.
09-12-2023 08:57 AM
Or how I can manually set static source port just for one host?
09-12-2023 09:54 AM - last edited on 09-13-2023 10:28 PM by Translator
post the config ?
show run
(removing any passowrd)
09-12-2023 10:28 AM - last edited on 09-13-2023 10:29 PM by Translator
interface Port-channel1.395
description Internet
encapsulation dot1Q 395
ip address *.72.*.102 255.255.255.248
ip nat outside
ip nat inside source route-map NAT interface Port-channel1.395 overload
ip route 0.0.0.0 0.0.0.0 *.72.*.97 name Default-Gateway track 255
ip access-list extended NAT
220 permit ip host 10.10.3.10 host *.67.*.200
230 permit ip host 10.10.3.10 host *.157.*.124
route-map NAT permit 10
match ip address NAT
09-12-2023 01:06 PM
There is no any additional config
09-12-2023 03:18 PM - last edited on 09-13-2023 10:31 PM by Translator
as per the information provide you have NAT using your port-channel interface
check the example
route-map
with NAT
coming back to your question what is the need to source port change in NAT ?
09-12-2023 11:22 PM - last edited on 09-13-2023 10:32 PM by Translator
There is some issue regarding SIP registration. ISP told me that he saw registration sourced with
port 65060
but when I was checking NAT was with
port 8172
09-12-2023 11:29 PM
I also have in another office Cisco 800 Router and there is no port changing during the NAT
09-12-2023 11:38 PM
I changed NAT configuration from interface to IP NAT Pool and right now source ports are the same.
09-13-2023 01:43 PM
glad all good and thank you sharing the solution
09-14-2023 07:04 AM
Hello Irakli,
To maintain the source port during PAT, you can't use traditional PAT. Instead, consider using a static NAT or port forwarding (Static PAT) rule that maps your internal phone server's IP and desired source port to a specific external port on your public IP address. This keeps the source port consistent for your SIP communication.
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