How can i static ip?

[j4uonline]

System: ubuntu 20.04, centos 7.9

command serve

how can i static ip?

I test with “serve” and it working

i use proxy and add it into extension oxylabs proxy chrome, and then check ip into the web https://whatismyipaddress.com is ok.

But when i watch youtube about 1 mimutes, and check ip again, it change?
And repeat the action, and it change again and again.

How can i control the ip, in case stop the change it and make it static?

thank for read and support.