Colony Survival Server Not Showing or Friends Can't Join

If your Colony Survival server is not in the Join Internet list, or friends see it but cannot get in, the cause is almost always one of these: the server was started as a LAN or non public server, the game and Steam ports are not reachable, the name is too common to find, the server is on a different build than the players, or the players are missing a mod the server runs. Colony Survival has no join by IP box, so everything goes through the Steam server list, and that list is only as good as the server's network setup.

Quick checklist

Symptom	Likely cause	Fix
Shows under Join LAN, not Join Internet	Network type is LAN or non public	Start with `+server.networktype SteamOnline`
Not in either list, console looks fine	Ports closed, or list still refreshing	Open the ports, wait, search by name
Listed, join hangs or times out	Game port reachable for queries but blocked for play	Check both ports, firewall, CGNAT
"Version mismatch" or join refused after a patch	Server on an old build	Update the server and restart
Joins, then kicked or stuck loading	Mod missing on the client, or different mod version	Same mods on both sides
Steam friend can join, others cannot	List problem, not a server problem	Network type and ports

A colony at night in Colony Survival

Cause 1: the server is not public

Colony Survival's server has three privacy choices when you start it from the server window in the game folder: Steam Public, Steam Non-Public and single player. On the command line the same choice is the networktype argument:

./colonyserver.x86_64 -batchmode -nographics +server.world "Frontier" +server.networktype SteamOnline +server.name "Frontier Colonies EU" +server.maxplayers 10

SteamOnline puts the server in the Internet list. A LAN network type only shows on the same network, which is why the host often sees it under Join LAN and assumes everything works. If you launch from a batch file or a shortcut, open it and check the argument. Then restart the server, since it only reads launch arguments at start.

Cause 2: the ports are not open

Steam needs to reach the server to list it, and players need to reach it to play. A home hosted Colony Survival server commonly uses ports in the 27016 to 27018 range for the game, plus the Steam port set with +server.steamport (27005 is a common value). Whatever numbers your launch line uses, open them as UDP on the router and point them at the PC running the server. Then allow colonyserver through Windows Defender Firewall on both private and public networks.

Two traps:

Double NAT. If your internet provider's modem is also a router and you have your own router behind it, forwards on your router do nothing. Put the modem in bridge mode or forward on both.
CGNAT. Some providers, including many mobile and 5G home internet plans, share one public address between customers. No forward can work then. See how to tell if you are behind CGNAT before spending an evening on router menus.

Our general port forwarding guide walks through the router side.

Cause 3: it is there, you just cannot find it

The Internet list is long, and servers with names like "Colony" or the default name are everywhere. A new server also takes a short while to appear after it starts.

Back out of the Multiplayer menu and open it again a minute or two after the start.
Type a distinctive part of the name into the search box instead of scrolling.
Give the server a name that nobody else uses, for example your group name plus a region.
Once one friend is in, the rest can join through that friend in the Steam friends list.

Cause 4: different game versions

Colony Survival is in Early Access and updates change the network protocol. When Steam updates the players' game, a server still on the previous build either drops out of their list or refuses the join. Update the server through SteamCMD (app ID 748090) or turn auto update on so it pulls the new build on each restart. If you run the public test branch on your client, switch back to the default branch to match the server.

Cause 5: mods do not match

The server does not download Workshop mods by itself, and it does not push mods to players. A modded server needs the mod folders uploaded on the server side, and every player needs the same mods, in the same versions, installed through the Workshop. A player missing one of them can see the server but fails to load into it, or gets disconnected during loading. Mods like Pandaros Settlers update often, so after a mod update, update the server copy too. The full mod setup is in our guide to hosting a Colony Survival server.

Cause 6: the player is blocked

If the server has a whitelist, only players on it can join, and anyone on the blacklist is refused. Both are managed with /whitelist and /blacklist commands in chat by a player in the god group. If one specific friend cannot join while everyone else can, check those lists before you touch the network. The commands are covered in our guide to Colony Survival admin commands and permissions.

Read the console

The server console is the quickest way to tell a list problem from a join problem. When a friend tries to connect, a log line about the connection attempt means the network works and the issue is version, mods or a block list. No line at all means the connection never reached the server, so look at the network type, ports and firewall.

A Colony Survival settlement during the day

Skip the network part

Causes 1 and 2 are the bulk of this problem, and both disappear on a hosted server. A GamezServers Colony Survival server starts as a public Steam server with its own address and its ports already open. The world name, server name, player cap and auto update are fields in the control panel, so the server stays on the same build as Steam players, and the live console shows each connection attempt. The world keeps running when you log off, and you can split the bill with your friends.

FAQ

Why does my Colony Survival server only show under Join LAN?

It was started with a LAN or non public network type. Launch it with +server.networktype SteamOnline, or pick Steam Public in the server window, and restart.

Can I join a Colony Survival server by IP?

Not from a direct connect box. Players use the Internet server list and search for the name, or join a Steam friend who is already on the server.

What ports does a Colony Survival server use?

The game port and the Steam port set on the launch line. Home setups commonly use 27016 to 27018 for the game and 27005 for Steam. Open whatever your launch line sets, as UDP.

Do players need the same mods as the server?

Yes. Every player needs the same mods in the same versions. The server does not send mods to players.

Why did my server disappear after an update?

It is on an older build than the players. Update it through SteamCMD or with auto update on, then restart.