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Port Range doesn't affect DCC CHAT requests

Posted By: Vilius

Port Range doesn't affect DCC CHAT requests - 17/02/11 01:31 PM

Hello,

I have a Port Range set 1024-1030 for DCC Send, Get and Chat request. At least DCC Send works fine and honnor the settings, however DCC Chat doesn't work. The client connects to completely random ports. 54235, 60710, 47889, and so on. Can anyone confirm?
Posted By: Riamus2

Re: Port Range doesn't affect DCC CHAT requests - 17/02/11 04:09 PM

Who is initiating the chat? You or someone else?
Posted By: Vilius

Re: Port Range doesn't affect DCC CHAT requests - 19/02/11 11:57 AM

I guess someone else, because I get DCC CHAT _request_.
Posted By: Riamus2

Re: Port Range doesn't affect DCC CHAT requests - 19/02/11 04:34 PM

You cannot control the port someone else uses when initiating chat. That is up to them. Just like if someone sends something to you. It will use their port range and not yours.
Posted By: argv0

Re: Port Range doesn't affect DCC CHAT requests - 20/02/11 12:22 AM

Note that if they are set to "Passive DCCs", it will reverse the connection protocol (the receiver chooses the port). However, I believe that the sender has to set passive mode on-- if you set it, and the sender does not, it won't make a difference.
Posted By: Riamus2

Re: Port Range doesn't affect DCC CHAT requests - 20/02/11 02:44 PM

Right. I considered mentioning that, but because the OP said the ports weren't matching his/her port range, I think it's safe to assume the sender doesn't have passive mode enabled. And you are right that the sender has to have it on for it to have any effect.
Posted By: Vilius

Re: Port Range doesn't affect DCC CHAT requests - 20/02/11 07:25 PM

That's strange. Then why DCC Send works in desired range? Send is also initiated by remote client.
Posted By: Riamus2

Re: Port Range doesn't affect DCC CHAT requests - 21/02/11 11:12 AM

"Send" would mean you are sending it to someone. Do you mean you're receiving it? If so, that also is not controlled by your port settings. As mentioned, the sender *could* use passive DCC, which can change who controls the ports, but this is usually not the case because it limits who can receive the files.
Posted By: argv0

Re: Port Range doesn't affect DCC CHAT requests - 21/02/11 07:00 PM

Send works in the desired range because, as we pointed out, the sender initiates the connection (it is not initiated by the remote client). Whoever initiates the connection chooses the port-- they can also choose to let the receiver choose the port, which is what passive mode is.
Posted By: Vilius

Re: Port Range doesn't affect DCC CHAT requests - 23/02/11 07:18 PM

Understood.

I'm just stugling to keep DCC working through our new corporate firewall which does block all outbound traffic except allowed ports. I'm in control of it but I don't want to open wide range of ports just for DCC. Maybe anyone has a suggestion how to solve this?
Posted By: Riamus2

Re: Port Range doesn't affect DCC CHAT requests - 23/02/11 07:38 PM

If you don't care too much about compatibility, then passive is a good option. It will work with anyone who either doesn't have a firewall/router or who can forward ports in anything they do have. If anyone you need to talk to or send things to can do that, then you can completely avoid forwarding ports in your firewall.

Otherwise, just make sure someone inside the company is initiating the dcc send or chat and that their port range matches your firewall port range. Make sure they don't have passive on. And make sure their port range is set to include chat and send. As long as all of that is done, it should work if the port range is forwarded correctly.
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