NetAutoClose - which port is used?

[Wolfgang Orth]

Hello Bruce and all,

over which port are the NetAutoCloseClients and -Server communicating?

I assume its UDP on Ports 2326, 2327, 2328, 2329 and 2330.

For some reasons I have Port 9 on my mind, no idea why.

Are these standard ports, which we couöd expect to be available on a LAN or may paranoid admins locked them too?

And why are there 5 consecutive ports?

Does the program rotate the port numbers? ]2326,  2327,  2328,  2329,   2330 from message to message?  ;-)

Thanks for any information, confirmation or correction,
Wolfgang

[Bruce]

Hi Wolfgang,

>> over which port are the NetAutoCloseClients and -Server communicating?

the "base port" is set using;
NetOptions(Net:SetDgPort, xx)
I don't recall the default values offhand, but it's worth noting that both UPD and TCP ports (with the same numbers) are used. You can use TCPVIEW.EXE to see what port range your app is using.

>> And why are there 5 consecutive ports?
The number of ports is set using
NetOptions(Net:SetMaxInstances,yy)
The default is indeed 5.
The reason for having more than 1 is because each Exe "uses up" one of the ports. Thus, when set to 5, 5 instances of the same program (or related programs) can be run on the same machine and they can still communicate with each other. Often you can set this down to 1 or 2 if you like. However bear in mind that on Terminal Service servers you might need a lot more than 5.

>> For some reasons I have Port 9 on my mind, no idea why.

me neither. We definitely don't use 9 for a default for anything.

>> Are these standard ports, which we could expect to be available on a LAN or may paranoid admins locked them too?

Obviously Admin's can do whatever they like on a LAN. However typically on a _Lan_ the machines on the Lan are free to communicate with one another. It's only once you get onto the Wan that things get blocked.

Cheers
Bruce

[Wolfgang Orth]

> but it's worth noting that both UPD and TCP ports (with the same numbers) are used

According to the manual the first UDP port is 2326, while the first TCP port is 2376. Each other following ports have a difference of 50.

Anyway, seems as if all works fine, as expected.

But maybe I don't get any negative response, because nobody makes use of it. But, hey, thats life!