topic Re: Dynamic DNS in Network Security

Dynamic DNS

Haziyah Ibrahim — Wed, 27 Oct 2021 07:19:32 GMT

How to configure Dynamic DNS on cisco asa ASDM? I want to connect it with No-IP.com. My public IP 202.186.57.121.

I've created a hostname for my connection, but I don't know how to verify if my configuration successful or not.

Re: Dynamic DNS

balaji.bandi — Wed, 27 Oct 2021 07:23:13 GMT

is your Public IP fixed or changes ? if fixed you can verify the same on Dyna DNS Site.

some reference :

https://www.cisco.com/c/en/us/td/docs/security/asa/asa84/configuration/guide/asa_84_cli_config/basic_ddns.html

you can test from external using FQDN name see if that packet reaches your ASA.

Re: Dynamic DNS

Haziyah Ibrahim — Thu, 28 Oct 2021 07:47:21 GMT

I've configured the Dynamic DNS, but I noticed that my public IP address changed. Can you explain why this happened?

Re: Dynamic DNS

balaji.bandi — Thu, 28 Oct 2021 08:53:08 GMT

I've configured the Dynamic DNS, but I noticed that my public IP address changed. Can you explain why this happened?

If you have Piublic IP Fixed or Dynamic ? if Dynamic then that changes based on the ISP DHCP Pool.

if that IP is fixed and changed, the question goes to ISP.

Look at at logs, we can not explain with out seeing what is configured what changed over there ?

Re: Dynamic DNS

paul driver — Thu, 28 Oct 2021 09:56:53 GMT

Hello
that’s the whole point of DDNS is if your isp assigned ip address changes(which can do frequently) But you have a dns recored that needs to be updated based on the old/new ip address of that isp assigned ip - then the DDNS client( your rtr/fw) would contact the isp provider that providing DDNS and the related dns recored would be updated with the new assigned isp address