Potential Port Forwarding Issue (maybe CGNAT?)
I'm creating a 1.20.1 forge server with ~70 mods for some of my friends. However, whenever I try to connect to it via my external IP address (I think that's what it's called) most of the time I connection time out, and only occasionally successfully connect. I've checked my portforwarding through https://canyouseeme.org/ and it comes back valid. Connecting to the server via the local device IP address works so that's why I'm inclined to believe it's a portforwarding issue. Looked into it a bit and I don't believe I suffer from CGNAT with my ISP (AT&T Fiber). The IPv4 address from my router configuration interface matches the public ip on https://whatismyipaddress.com/ and it doesn't fall into any of the CGNAT ranges. Previously, I have hosted forge servers on this computer with my last ISP (Xfinity), but that was cable instead of fiber, not sure if that would have any impact at all.
Looking for any troubleshooting techniques / solutions
Open Port Check Tool -- Verify Port Forwarding on Your Router
A free open port check tool used to detect open ports on your connection. Test if port forwarding is correctly setup or if your port is being blocked by your firewall or ISP.
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In this test, the [INFO] Public IPv4 and [INFO] Public IPv6 lines had the same IPv6 format address
Odd
you port forwarded, internally (ur machine) and externally (ur router) ?
only my router ...
you uh, need to do on ur pc too :yes:
thats why it shows Not Open tcp port
how to do that?
I selected my PC as the device to port forward in my router
Database Mart
YouTube
How to Open a Port in Windows Firewall
#WindowsVPS #windowsFirewall #VPS hosting #Port
Sometimes, well-known applications (for example, SQL Server ) get blocked by the Microsoft Defender Firewall. When this happens, you'll need to manually create a rule to allow them to access the network. This video will teach you the steps to open a port to allow an app to communicate outside the n...
thats a pretty good video i found ngl, damn
ah its a windows SERVER, but good enough
roughly the same process for a windows pc
I added both inbound rules for 25565 TCP and UDP and the Command Line test still says TCP not open. Not sure if you saw earlier in my post but https://canyouseeme.org/ sees the open port, also I have hosted before on this computer fine
Open Port Check Tool -- Verify Port Forwarding on Your Router
A free open port check tool used to detect open ports on your connection. Test if port forwarding is correctly setup or if your port is being blocked by your firewall or ISP.
inbound and outbound?
yes
hmm not too sure
iβd check online or ask ai (common situation most high level thinking modes will give good answers)
i gotta sleep lol
can you connect locally
yes connecting locally works
via
local host
or
the 192.168 local device address
from another device?
yes
localhost only from hosting pc
but the 192.168.x.x works
yeah thats normal
do you know if you have a somewhat static wan ip
what does that mean
is your public ip somewhat static
I believe so
In the time I've spent trying to troubleshoot / setup
my public ip has remained the same
and connecting to public ip only works sometimes?
yeah
other times it connection times out
wtf
yeah idfk
is the hosting pc windows or linux?
windows
I tried hosting on my mac mini as well
same issue
Run in powershell
with server on?
yeah
and paste output here
pasting ip ok?
you can blur that out, it doesnt matter that much
ok well
its the exact same as this
again
PS C:\Users\dawso> iex (Invoke-RestMethod -Uri "https://raw.githubusercontent.com/DominicTWHV/Is-It-CGNAT/refs/heads/main/windows.ps1")
[INFO] Public IPv4: 2600:1702:5c61:c040:31ef:a3b9:8c68:2306
[INFO] Public IPv6: 2600:1702:5c61:c040:31ef:a3b9:8c68:2306
Please now confirm your Minecraft is turned ON and running properly.
Which port does your Minecraft server run on? (e.g., 25565): 25565
[INFO] Default Gateway: 192.168.1.254
[INFO] Running traceroute for IPv4...
Tracing route to DAWSON-PC.attlocal.net [2600:1702:5c61:c040:31ef:a3b9:8c68:2306] over a maximum of 2 hops: 1 <1 ms <1 ms <1 ms DAWSON-PC.attlocal.net [2600:1702:5c61:c040:31ef:a3b9:8c68:2306] Trace complete.
[INFO] --------------------------------------
[INFO] No CGNAT detected. Only one or no internal IPs found.
[ERROR] Error checking port 25565. Ensure you have internet access.
[ERROR] You should not be behind CGNAT for IPv4, but your TCP port 25565 is not open.
PS C:\Users\dawso>
ah i think i know whats up
do you have ipv4?
I believe so
on my router configurator there's an "IPv4 Broadband"
that is very weird, normal ipv4 conditions should not display ipv6 in the output field
i have never seen this happen before actually
this is what my router tells me
and when I check my ip online
it shows the "Broadband IPv4 Address"
for IPv4
the same one?
yes
wtf π
unless the v4 api i used is down
you want me to try to run the linux command line on my mac?
can you try visiting https://api.ipify.org/ and see whats the output?
the linux version is outdated, i never got to updating that
the output is my IPv4
like
the actual IPv4
hm, interesting
this number
broadband ipv4
are you using your main pc to host?
I want to use my secondary mac mini to host but I've been troubleshooting on my main
so yes
have server files on both computers rn
this is weird as fuck
what router is that?
BGW320-505
AT&T provided it when we upgraded to Fiber plan
shit goes for $60 on ebay π
it may or may not be a router issue tbh
cant think of anything else
you think maybe IP passthrough would work?
would probably trash your entire network
it should be the same thing as bridge mode
which if works, turns off nat
rip
you could try playit.gg
does that support modded?
ye, its just a tunnel
hold on
modded?
forge or fabric?
forge
which modpack
custom
I have a curseforge code if you want to see the mods π
uh no need
how many mods
72
any heavy ones?
create + addons
thats about it
can you move the mods and world somewhere else and then try without any mods?
tried
make sure dont delete them
doesnt work?
yup
ill try again
i mean, gg, i cant come up with anything else. If this time it still doesnt work, you may be stuck with playit
I tried playit.gg
it works
how reliable is the tunnel do you know?
somewhat reliable
yeah I just tried again with pure vanilla server and same issue
damn
gg
might be a router issue then
wtf man
yeah
we all know isps dont give good things to their customers anyways
real
Just to confirm, can your friends connect via your external IP fine?
Is this only your connection via your own external IP?
If so, this requires a setup called hairpin nat, which isn't always setup on ISP routers. Internally, when on the same internet connection as the server, you should be using the internal IP to connect, while people outside should be using your external IP to connect.
I have not tried this Ill get back to you
Yup this worked, anyone not on my hosting internet can connect
Yeah, then that's something called hairpin nat, you can either fix this if your router supports it, or add a DNS overwrite for your machine/local network to go to the local address instead
Yeah ill probably just connect locally via the local device address
Thank you so much
No worries, have fun
Read the whole discussion hoping someone would mention that, I always thought it was how it worked for everyone (external IP not working from within local network), isnβt that the default ?
It's the default for most, but it's possible to enable or is enabled by default for some.
Thanks for the knowledge π