Port forwarding with a Linksys router

[Despard]

OK, even though I'm a volunteer/tech I manage to get stuck sometimes. This is one of those times, and it's really annoying me. Networking isn't my speciality, though I am learning more about it. I'm having huge problems with setting up port forwarding on my LinkSys router.

My iMac G5 is connected to a router along with three PCs. It accesses the internet fine (obviously!) though I want to make it an ftp server, i.e. forward ports 20-21 to the relevant ports on my Mac.

So first I configured my Mac to have a static IP (192.168.1.24 in this case) instead of using DHCP from the router. That works fine. Then I configured the port forwarding on the router to forward ports 20-21 to ports 20-21 on my Mac, at the IP address 192.168.1.24.

But this doesn't have any effect. For some reason, nobody can connect to my ftp server. I tried a similar thing a while ago with a p2p program, and that didn't work either.

I have scanned for open ports using the Network utility (from Aqua and the command line) and the only open port on the router is port 80.

Anyone got any thoughts? This is really irritating!

Carl

 

[scruffy]

Does your ISP block inbound ports 20 & 21? Wouldn't be that surprising if they did.

When you scan the router for open ports, where are you scanning from - are you actually behind the router? Because you don't care what it looks like from the inside, you care what it looks like from outside...

 

[g/re/p]

I could be mistaken, but for what you want to do the WAN
port on your router may need to be configured with a static
ip provided by your ISP.

 

[Despard]

Does your ISP block inbound ports 20 & 21? Wouldn't be that surprising if they did.

I don't know. I'll try and find out.

When you scan the router for open ports, where are you scanning from - are you actually behind the router? Because you don't care what it looks like from the inside, you care what it looks like from outside...

Good point! I have tried using one of those web-based port scanning utilities... I'll try again later.

 

[nixgeek]

I could be mistaken, but for what you want to do the WAN
port on your router may need to be configured with a static
ip provided by your ISP.

Not necessarily. You can set up a dynamic domain name with someone like DynDNS.org or No-IP.com. This is helpful if you want to host from your location but don't have a static IP. Most routers have this option available and they update the service with the new IP lease once it's given. There's even software for your computer provided by these DDNS companies to do the same thing.