How does your port forward rule look? Do you have multiple routers at home?

Possibilities:
- UFW enabled on your Ubuntu Server?
- Your server is behind another router than the one the internet comes in on.
- Port forward error? You look like you know your stuff, but just a consideration.
- Your ISP puts you behind CG-NAT (Does the public/WAN IP on your router look different than the one GMod dedi server console shows you?)

One way or another, we'll get your server online.

Originally posted by ꧁Jay꧂:

How does your port forward rule look? Do you have multiple routers at home?

Possibilities:
- UFW enabled on your Ubuntu Server?
- Your server is behind another router than the one the internet comes in on.
- Port forward error? You look like you know your stuff, but just a consideration.
- Your ISP puts you behind CG-NAT (Does the public/WAN IP on your router look different than the one GMod dedi server console shows you?)

One way or another, we'll get your server online.

- Do you have multiple routers at home?
No, just the one connected to the ISP's modem.

- UFW enabled on your Ubuntu Server?
Yes, with ports 27015 & 27005 open on both UDP/TCP (Same with the router).

- Your server is behind another router than the one the internet comes in on.
ISP Modem -> Home Router (ASUS RT-AX86S) -> Server. It's very odd because its a very simple layout and I have another Ubuntu server with the same networking layout running a Minecraft server on port 19132 and players are able to connect just fine. I even tried hosting a test server on the Ubuntu bare metal machine (same one the Minecraft server is running on) and ran into the same issue. At first I thought it might be hardware on the server but now I am beginning to believe its most likely port, ISP, or network related.

- Port forward error? You look like you know your stuff, but just a consideration.
Double checked, re-checked. Even tried DMZ to forcefully open ports for that local IP address but no luck.

- Your ISP puts you behind CG-NAT (Does the public/WAN IP on your router look different than the one GMod dedi server console shows you?)
They are the same. When I boot up the server it shows the exact IP address that is on my router admin panel for WAN.

V From console V
Connection to Steam servers successful.
Public IP is xx.xx.xx.xx. <- Same as router WAN

However, I do get this,

Network: IP 192.168.50.215, mode MP, dedicated Yes, ports 27015 SV / 27005 CL

And I've gotten this when I don't bind the IP on the startup command, (Loopback IP Address)

Network: IP 127.0.1.1, mode MP, dedicated Yes, ports 27015 SV / 27005 CL

Now, shouldn't this line within the startup actually show my public IP?

Network: IP (Public IP), mode MP, dedicated Yes, ports 27015 SV / 27005 CL

I've actually tried bind the public IP address to startup but got a port binding error spammed on the startup boot. I know that likely isn't the issue but I've quite literally gone insane trying these potential fixes.

I've ran a Gmod server on a VPS a while back and both this line above and the Public IP at the bottom of the startup were the same public IP. I'm not sure on the networking implications on that side of things (VPS vs self host) but I can't see how that is any different compared to my setup.

Also, I'm sorry if my response seems overwhelming or a bit confusing. I am trying to get all my thoughts out on the issue and trust me, there are a lot of thoughts.

Might end up calling the ISP but I have a feeling its something to do with the router.

Hey Ploopy,

I don't know what timezone you're in, but perhaps we could schedule a window to tackle this.

To respond to your comments regarding the strict IP binding, on VPS they typically have a public IP directly assigned to the network adapter but at home it's rare for that to be the case- so it is correct to be your 192 address.

You could perhaps try port forwarding a non-standard port? Maybe do a "tcpdump -i any dst port SRCDS_Port_Here" and try to have people connect, if you aren't seeing any data populate then the traffic is not reaching your VM and would take that part of the equation out.

Your ISP may have had made a change on their end for all we know, it is strange for it to have worked in the past but suddenly no longer.

Are you close to US East, by chance?

Originally posted by ꧁Jay꧂:

Hey Ploopy,

I don't know what timezone you're in, but perhaps we could schedule a window to tackle this.

To respond to your comments regarding the strict IP binding, on VPS they typically have a public IP directly assigned to the network adapter but at home it's rare for that to be the case- so it is correct to be your 192 address.

You could perhaps try port forwarding a non-standard port? Maybe do a "tcpdump -i any dst port SRCDS_Port_Here" and try to have people connect, if you aren't seeing any data populate then the traffic is not reaching your VM and would take that part of the equation out.

Your ISP may have had made a change on their end for all we know, it is strange for it to have worked in the past but suddenly no longer.

Are you close to US East, by chance?

Whats odd is that its showing the port is open (27015) while the server is running but somewhere in the background not properly being routed to the gateway? Very unsure of this. I am able to ping both my gateway and google DNS on the host machine. I just tried using a different router from our previous ISP (We just switched) and used a completely different public IP address and still no luck connecting from the outside (Tested this using phone hotspot). I even when one step further and created a new Ubuntu VM with a fresh install of Garry's Mod but still no change. I think I can cross the ISP being an issue considering that I have used both my old and new ISP and got the same result.

Different machines, different ISPs, different gmod server saves, fresh installs, what else could I possibly do?

I am on CST so one hour behind you. I really appreciate the help so far but if you're up for it we could hop on discord for a 1 on 1 to hopefully diagnosis the problem. Let me know your schedule and, again, I really appreciate the help so far. Thanks!