Forums Bug Reports mIRC6.16 DCC Chat Port Number Bug

Regardless of whether I specify ports in the options or not, a port number over 57000 is always sent in the PRIVMSG when I intiate a DCC chat. I've tested port status by specifying the ports and using $portfree immediately before and after the chat command in a script. The ports show as free before the command but the first port in the range shows busy during the connect. From that I assume the correct port is being used on my machine even thought an incorrect port number is being sent.

I cannot say if this first occurred in version 6.16 or not since I upgraded from 6.12. The only possible reason I can guess that I am experiencing this and nobody else has reported it previously is that I am running Win XP Pro (32bit) on a 64-bit cpu.

chnaged your hardware setup to the internet at all, like a router otr a NAT? that does port remapping, and might be the problem. (might not be as well).

Thanks for the suggestion, Dave. But that couldn't possibly cause a problem like this. The port number is selected in the mIRC client initiating the chat and a PRIVMSG containing port number and ip address is sent. The initiating client is supposed to select the port nmber from the range set in the options. Even if there were a mapping problem, the client couldn't possibly know that and would still select from the set range.

Maybe it would go outside that range if all ports within range were busy, but I don't think so. But it doesn't matter since, as shown in my test, ports within range were free.

It really does look like a bug and not a prolem with system configuarion.

I believe that the reason dave asked is that some forms of nat will change the port within the ctcp that mirc sends out, which could conceivably cause a problem. mIRC might be sending out a port in the right range, only to have the nat change it in the outgoing ctcp. Ideally, the reciever would connect to that port on the internet side, but the router would remap the traffic internally back to whatever port mirc picked in the first place.

If you haven't already, you might try opening a debug window (/debug @debug, for example) and try an outgoing dcc. look at the port number that is sent out and compare it to what the reciever sees.

A NAT designed to change the message section of a datagram? That seems highly unlikely. But, I'll give what you suggested a try. Stranger things have happened. Thanks

Hrung hit the nail on the head, and yes NAT's do do that. exactly that, but some NATs they miss the dcc resume request comming back from the reciever tho and aresume request on some unknown port number gets recieved by mirc and it just ignores it as an invalid request.