Firewall Killed The Chatter

I have been using mIRC on my home PC for a few years. I find it to be an invaluable tool for keeping in touch with people and also find it to be a useful research tool. I just started working for a new company and thought that it would be useful for me to have access to my mIRC clients while at the office. So I tried to install mIRC on the PC at my office, but I just can’t seem to get it to work. I believe I installed it correctly, but no matter what I try, it still won’t connect to the mIRC service. My Internet access and e-mail all function fine, so I know it’s not my connection. What am I missing?

It’s helpful if you can send us as much information as possible so that we have a better chance of solving these kinds of problems Specific information about your network environment and perhaps a copy of any error messages you might have received would be useful in this case. In spite of this, though, I think this problem is straightforward enough for me to explain your current difficulties.

Since you’re using mIRC (the Windows version of Internet Relay Chat) on your home PC, I think it’s a safe bet that you installed it correctly at the office. Further, since you have access to the Web and e-mail, we can also rule out any problems with your Internet connection. This strongly suggests that your company could be using a firewall to block the ports that mIRC uses when establishing a connection.

This is a common practice in a corporate environment. Many companies have strict firewall and security policies in place and seriously frown upon employees installing software on their workstations without first gaining authorization from the network administrator. An application like mIRC is typically blocked by the company firewall for a variety of reasons. In addition to being a potential security risk, applications like mIRC tend to decrease employee productivity levels. Not to mention the fact that mIRC has a reputation for hosting sexually explicate sites that could leave the company liable to a potential lawsuit.

However, if you could prove to your company’s network administrator that you have a business need for the mIRC client and get permission from your manager to use it, then he might be willing to open up the necessary ports on the firewall for you. I say might because mIRC could require wide range of ports.

For starters, mIRC makes use of UDP port 113 for establishing your identity. Then you’ll need to open up TCP ports 6660 – 6669. I believe that port 6667 is the one generally used, but to be safe you should probably open all of them. The area where your network administrator is undoubtedly going to have the biggest concern is regarding mIRC’s DCC functions. To use this feature, ports 1024 -5000 will need to be configured to allow mIRC traffic to pass over it. If this is something he’s willing to entertain, then he could find more detailed information on mIRC and its ports requirements at

Once these ports have been resolved you shouldn’t have any trouble accessing mIRC on you office PC.

I have two PCs that share an Internet connection through a cable modem. Both PCs connect to the network via RJ-45 Ethernet cables, and the cable modem connects to a NetGear RP614 router. One computer runs Windows 2000 Professional, and the other one runs Windows XP Home Edition. This is the machine that’s giving me a problem.

The Internet connection on my Win 2000 PC runs just as it always has, yet when I access the Internet with the XP system, the connection is extremely slow. Web pages take almost a minute to load and occasionally time out. This behavior is consistent whether or not the other PC is also online.

Both PCs can ping each other, and I can print over the network. I have uninstalled and re-installed the network adapters, the modem and the TCP/IP protocol. I tried upgrading the network drivers, but nothing has changed. I even tried moving the slow PC to a different port on the hub hoping that it might just be a bad port. It wasn’t. As a final act of desperation, I contacted my ISP and had it perform diagnostics on my cable connection and according to them everything checked out just fine.

The most frustrating thing is that this isn’t a new configuration. I have had all of this equipment in place for almost a year now and everything worked fine. Any suggestions on what I could try next to resolve this problem would be greatly appreciated.

Well, I have good news and bad news for you. The good news is I don’t think your problem has anything to do with your hardware or your network configuration. Just the fact that all of this hardware was purchased, installed and had been working for over a year pretty much rules it out. Now, could something have happened to the hardware to cause this? It’s possible, but the odds are against it.

This brings us to the bad news. From the way you described it, to me, it sounds like it has more to do with a software incompatibility or resource/memory shortage. Unfortunately, isolating the problem could be extremely difficult and it’s nearly impossible for me to instruct you on within this limited forum. Typically you need to identify exactly when things started to go wrong. You’ll find that it usually corresponds to a time when you installed a new piece of software, updated a driver or applied a service pack. The best way to prevent this in the future is to use a utility like Microsoft’s System Restore before installing or updating anything on the PC.

System Restore lets you can revert your system to a previous time when the system was stable and working properly. System Restore monitors changes to the system and some application files, and it automatically creates easily identified recovery points. You can configure System Restore to automatically create recovery points daily or at the time of significant system events (such as when an application or driver is installed). You can also create and name your own restore points at any time.

While this might be helpful for you in the future, it does nothing to resolve your immediate problem. This is where the real headache comes in. If you can’t isolate when the situation changed, the easiest thing is to reformat your PC’s hard drive and then reinstall Windows XP Home Edition (don’t forget to backup all your data files first).

Over the years I’ve discovered that Windows-based computers need to be erased and reformatted on almost a yearly basis in order to keep them running at peak efficiency. You see, over time Windows becomes bloated with numerous utilities, applications, driver updates, security patches and so on. That bloat has a tendency make the system unstable. Regrettably, reformatting the system is usually the only way to effectively get rid of these mysterious problems. It’s unquestionably a hassle, but it will usually give you the best results.

My only other suggestion is to thoroughly scan your system for viruses. The symptoms you described sound as though they could be viral in nature, and that’s worth investigating.

Adapted from, part of the Network.

Do you have a comment or question about this article or other small business topics in general? Speak out in the Forums. Join the discussion today!

Must Read

Get the Free Newsletter!

Subscribe to Daily Tech Insider for top news, trends, and analysis.