Problems in opening the 5029 port

Hello, I'm having some problems in opening a server in SRB2.
I just don't know how to open the port, I'm not an expert in this kind of stuff and I wasted three days in trying to open the port.
Main problem is this: in my router I can't find the "Port forward" option anywhere, all I see under NAT is:
Virtual Servers
Port Triggering
DMZ Host
ALG

I tried to set the 5029 port, my IP and "UDP" in both Virtual Servers and Port Triggering but still it looks like that nothing changes, Am I doing something wrong ?
Searching in the forums didn't help me a lot and also my router is an "Atlantis", and the HTTP page to configure it looks pretty different than the others, so not even tutorials around the web are helping me out.

I looked up Atlantis routers and got this page. http://screenshots.portforward.com/routers/Atlantis_Land/WebShare_111/Virtual_Server.htm It looks like the Virtual Servers tab is what you want.

Pick a rule address that isn't being used, set start and end to 5029, and set the local address to your computer's local address. If you need to find that, open a command prompt window (you can do this by opening the Start menu and searching for "cmd", then opening the first program that shows up - you may have to right-click and Run as Administrator?), then type "ipconfig" (without quotes) and hit enter. Look for the option that says "IPv4 Address" and that's your local address. Copy that in the field given. (You may also want to set up a similar rule for port 28900, which is what the Master Server uses, but I'm not sure on that end.)

If that doesn't work (like it doesn't on my router for some reason), you can put your local IP in the DMZ, which should send all incoming connections on all ports to it, but don't leave it like this unless you know what you're doing. If you have to do that you should take it back off whenever you aren't hosting.

If you find yourself having to set this up again constantly, you may want to assign your computer a reserved IP in your router's settings. Unfortunately, I can't find any information online for how to do this on an Atlantis router, so you'll just have to look around all of the settings pages for anything that mentioned reserved IPs.

If you find yourself having to set this up again constantly, you may want to assign your computer a reserved IP in your router's settings. Unfortunately, I can't find any information online for how to do this on an Atlantis router, so you'll just have to look around all of the settings pages for anything that mentioned reserved IPs.

Click to expand...

Isn't setting up a static IP easier and generally the thing we usually tell people to do when they want to host, without needing any info on the router?

They're the same thing. Some routers just call them reserved instead of static.

Aren't static IPs set up from the network adapter properties, for which you don't really need to know which brand your router is, and reserved IPs set up only in (certain) routers?

Okay, I'm updating this situation:
I opened the 5029 port and it worked actually very well for a pair of days (considering my not-so-great internet connection), then today I opened a server, let two of my friends to join it and we played for 15 minutes, then I invited another friend to play with us, but he wasn't able to find my server on the list.
I checked the Master server from this page (https://mb.srb2.org/masterserver.php) and I see "unknown "and "?/?" on my server, like it wasn't working (which is pretty strange, considering the fact that I was actually playing with two friends in that moment) and right now I'm not able to open working servers anymore.
I don't think that 5029 port is the problem right now, and it doesn't work even if I disable antivirus and firewall... any idea about what could be the problem ?

Edit: now seems to be working again... I don't know what happened :/