IPFW ipfw setup keyword - with and without ...

[absduser]

Here are two simple rulesets:

10 allow tcp from any to any established
20 allow tcp from any to any 22
65535 deny ip from any to any

OR:

10 allow tcp from any to any established
20 allow tcp from any to any 22 setup
65535 deny ip from any to any

The difference is that the second ruleset has 'setup' modifying the rule that lets in the traffic we want.

From what I can tell, in actual day to day use, these two rulesets behave identically.

Am I correct:

I *think* the difference between these is that the second ruleset (with 'setup') is slightly stricter because TCP *fragments* that are not part of any connection would be allowed through the first ruleset, but would be blocked by the second ruleset.

Because only a TCP fragment would be *neither* part of connection setup *nor* part of an established connection.

Is that correct ?

 

[absduser]

Is it possible for a moderator to change these to the general "networking" forum where perhaps more people could see them ?

I was not aware I was asking such a difficult question so perhaps it would be useful to have an answer for future searchers/readers ?

Thanks.