Cannot connect to friend's Local Server

[saltyJeff]

So my friends and I play l4d2 with one of us hosting a local server.
I have 2 friends, let's say Alice and Bob who are perfectly fine joining each other's server

However, when I try to join either a server hosted by Alice and Bob, I get the error "disconnected after 10 tries". When I host and Alice and Bob attempt to join my server, they get the same error.

Below is a pastebin of the console:

https://pastebin.com/T8vsALnB

I join servers by having one of Alice or Bob go to steam and hit invite friend.
As you can see around line 38 (Connecting to public(192.168.1.118:27015)) the public IP the steam invite feature gives me is a local one (192.168 range). Neither Alice nor Bob are on my local network so I don't understand why the steam invite is in the 192.168 range, and since they're not on my LAN of course I cannot connect to their servers. Also, direct connect using the connect command in the console doesn't work either. How can I connect to their servers and have them connect to mine?

Any advice on this error is appreciated. Thanks in advance.

[Fruittymcnutty]

I don't know if this will help you or not. It's been awhile since I spoke of this, so I might not be totally accurate. I was having trouble awhile back joining localhosted games, and having people even able to connect to mine. Someone that I used to be friends with told me to put this into the console.
/ip
or something like that. It should then show your public IP address. If it says "localhost", then you need to google "my ip" and copy your public IP address. then tab back into the game, and type /ip (paste your IP here, and disregard the "()")
Once you've done that, do /ip again, and it should show your public IP address. After I did that, I was able to host/join other people's games. I had no idea why it changed, though, so it might have been an update, or maybe my IP actually changed and I had to swap it manually?
This worked for me, I hope it does for you.
P.S. I'm not sure if there was a space between /ip and the address itself or not, but I feel like there was. Try both out if one doesn't work.

[flipya4real]

after you get their public ip, familiarize your self with the ping command and use it to ping their ip+port l4d operates on. if the packets fail the connection likely has a security problem like a local security (firewall, netsec, etc), or more likely a port being blocked in the router/modem firewall.

[Fruittymcnutty]

I didn't even need to get the other person's IP. This made me able to join via the regular menus.

[flipya4real]

Originally posted by Fruittymcnutty:

I didn't even need to get the other person's IP. This made me able to join via the regular menus.

it read to me like you were hosting. i might be off base but it looks like op is connecting to an external ip. just trying to help.

in any case i'd imagine you updated a connection line in a config file, depending on how long your client is open it may not get updated until next launch and internet services have massive pools of ip's. dsl is known to change fairly frequently.

[HarleyIsntReal]

Because you don't live very close, you get ♥♥♥♥ ping. You also can't play if you have certain mods. Why do people not understand that?

[Fruittymcnutty]

I was trying to BOTH host, and join. It failed on both before I did this. It used to work fine beforehand, then it suddenly said "Nope!" and I had to do this.

[Fruittymcnutty]

Originally posted by "Roach":

Because you don't live very close, you get ♥♥♥♥ ping. You also can't play if you have certain mods. Why do people not understand that?

If the host types something like "sv_consistency 0" into the console, people should be able to join if you're hosting mods that are normally blocking people from joining.

[saltyJeff]

To fix it I just revalidated game cache and reset my TCP stack. I just don't understand why I had to do that:
My Windows firewall is set up to allow L4D2 any ports it wants
NAT punchtrough means I shouldn't need port forwarding
I asked them for their external IP and was still unable to connect directly through the console "connect" command.

But the real question is why I would need to ask for their external IP at all? Shouldn't invite to game default to handing out an IP that isn't in the local subnet mask? Maybe there's someone at Valve engineering who can answer why. But after the game cache reset made it work again somehow so maybe the error was something with a file being written like @lebaneseblonde

I am using cable not DSL though, so my dynamic IP doesn't shift too much though.

More details:
I was using mods, but we all made sure to download the same one, and the error said "Connection failed after 10 retries" instead of a consistency error
@Coach we play on the same ISP and our ping is under 23 reliably (I checked using ping and tracert)
Hosting local games should punch through the NAT rather than need port forwarding right? IDK about the network topology but since person A and B can connect to each other the error shouldn't be blocked ports.

[Blaquicat]

Originally posted by saltyJeff:

(Connecting to public(192.168.1.118:27015)) the public IP the steam invite feature gives me is a local one (192.168 range). Neither Alice nor Bob are on my local network so I don't understand why the steam invite is in the 192.168 range, and since they're not on my LAN of course I cannot connect to their servers. Also, direct connect using the connect command in the console doesn't work either. How can I connect to their servers and have them connect to mine?

Its virtually impossible to connect inside someone else network.

If your friends directly join his server, if you follow him, you wont be able to connect.

Your friend has to start the server using the public (external) ip, preferentially from lobby, this way the masterserver wiill register the right public ip, not the internal one.

[Blaquicat]

Originally posted by saltyJeff:

But the real question is why I would need to ask for their external IP at all? Shouldn't invite to game default to handing out an IP that isn't in the local subnet mask? Maybe there's someone at Valve engineering who can answer why. But after the game cache reset made it work again somehow so maybe the error was something with a file being written like @lebaneseblonde

Because theres no way to reach somewhere without know the address(ip is address), if i said i live on apartment 13 on Block C, can you get here?

Originally posted by saltyJeff:

T
NAT punchtrough means I shouldn't need port forwarding

This game dont support that or upnp, this means you WILL NEED portfowarding, unless using hamachi or something.

[saltyJeff]

I guess I need more details:
I can connect to the lobby OK so it can't be an IP issue (or else how are we coordinating chat thru the lobby)
I only get the connection error when the game starts.

[Blaquicat]

Originally posted by saltyJeff:

I guess I need more details:
I can connect to the lobby OK so it can't be an IP issue (or else how are we coordinating chat thru the lobby)
I only get the connection error when the game starts.

You aren't connected to a server while in lobby, lobby does not requires anything, not even a server.
The thing starts when you hit start, no portforwarding no connection at this point (10 retry error)

[myljach twitch]

Originally posted by saltyJeff:

I guess I need more details:
I can connect to the lobby OK so it can't be an IP issue (or else how are we coordinating chat thru the lobby)
I only get the connection error when the game starts.

It is IP issue. If you may connect to lobby that does not mean it will work opposite.

https://steamcommunity.com/sharedfiles/filedetails/?id=818399628

[flipya4real]

Originally posted by saltyJeff:

But the real question is why I would need to ask for their external IP at all? Shouldn't invite to game default to handing out an IP that isn't in the local subnet mask? Maybe there's someone at Valve engineering who can answer why. But after the game cache reset made it work again somehow so maybe the error was something with a file being written like @lebaneseblonde

you shouldn't have to ask for their external ip. this is just how you manually connect in these situations. ping (ip): (port) should tell you if the route is clear. tracert will tell you where packets are getting killed or are slow - generally this is helpful when you have a ton of hops or you are on different isp.

as for the local subnet - it was just my guess that there is a config file the server/slaves use to coordinate connection, might have needed updating (subnet vs external). i'd have to take a look and i'm a bit fuzzy :)

seems like blackcat explained upnp and lobbies right. but it's fixed for you, so cheers!

[Kris]

Ah, my friend had this issue. It was the Firewall causing the problem, I suggest you check it.