The first question is, "Do you have an ADSL modem, or do you have an ADSL modem and router?"
An ordinary ADSL modem doesn't block ports, although your operating system (Windows XP), or your Internet Service Provider can block ports.
Usually the ports an ISP will block are things like FTP, or HTTP server ports. They don't want you using your ADSL for file or web servers.
A router usually blocks ALL ports coming in from the Internet, but doesn't block ports going out to the Internet. When using DCC, the computer that is sending the file has to have a port open coming in to it (I know it seems backwards). Unless you want to send files, or start DCC chat sessions, you shouldn't need to open any ports. Sometimes people asking you to get files from their DCC file server don't have their system configured correctly. Don't assume the problem is caused by your system.
The "identd" port is a separate issue. You probably do need to allow connections to come in to your computer for port 113, to make "identd" work. You can make port 113 available for one computer on your network, or in some cases multiple computers. Most Internet providers don't block port 113.
You are responsible for (and authorized) to maintain the equipment on your premises. If your ISP has locked you out of the settings for your modem or router, there are a few things you can do.
Ask them for the password, since the equiment is on your premises. If you are in the United States, contact the FCC regarding the exact regulations. If your ISP is violating the regulations, file an FCC complaint.
Download the manual for your modem and router from the manufacturer's web site. The manual will tell you the default password to get into the modem or router. Try that first. Most service technicians don't bother setting passwords. First, it takes extra time, and second, unless they set the exact same password for everyone, they would have a record keeping nightmare.
Most modems or routers have a factory reset function, that will reset them to default settings (including the password). Usually you press and hold the reset button for a long time. You should only use that as a last resort, since you have to know how to configure the modem or router after you reset it. You can call your ISP for help with that, but it's better if you understand how to do it. Your ISP tech support may not know how.
Another option is to change to a different ISP that has better technical support, or will give you the password to get into your ADSL modem or router.
