topic Re: How cgnat allocate ports in General Topics

How cgnat allocate ports

victor_cortez — Fri, 12 Mar 2021 18:01:34 GMT

Hello folks,

How checkpoint calculate ports of cgnat for each ip?

For example in my case show 904 ports for each client. What they mean "...to the same destination" ?

if my source is /8 to /22 how many ports for each client? when will it realease the port for another ip to use? just when the sessions is closed?

Re: How cgnat allocate ports

PhoneBoy — Fri, 12 Mar 2021 20:13:52 GMT

It means to same destination IP.
Source port and destination IP are used to differentiate connections between hosts you doing HIDE NAT for.
I presume the calculation is based on the number of addresses you are hiding for (/8) versus the number of public IPs you have (/22), assuming about 50k available ports for each public IP.
And like noted: it’s per destination IP accessed (not per source).

Generally the port is released for reuse a short time after the connection is closed/timed out.