ERROR[ServerThread]: Server: peer_id=2: failed to emerge player [FYI]

[RabbiBob]

I've seen a few threads, internet posts, etc while looking into this error this morning. I was putting together a fresh minetest server at my house and kept running into "ERROR[ServerThread]: Server: peer_id=2: failed to emerge player". I tried stock, I tried different client builds on a different PC (some people were looping back, this may or may not speak to that, but I believe the fundamental issue is the same) and all had the same error.

I then remembered that I had multiple ports on the machine (it's in the attic, I rarely ever see it) and that awhile ago I had activated a second port (if you don't have multiple NICs, it still is the same issue at the network level) and I checked my routes. Bingo. Switched to the other port and instant connection.

Code: Select all

[07:32] <Rabbi_Bob> I'll puke this out so it's in a log somewhere, it may help someone else
[07:33] <Rabbi_Bob> I'm running Ubuntu 12.04LTS on a headless machine (no desktop\gui\etc) and the box has multiple NICs (5).
[07:34] <Rabbi_Bob> If my client machine (172.25.4.100) connects to the first port of the server the following occurs
[07:34] <Rabbi_Bob> Client -> Server: connection handshake
[07:34] <Rabbi_Bob> Client <- Server: ERROR[ServerThread]: Server: peer_id=2: failed to emerge player
[07:35] <Rabbi_Bob> Client -> Server: continues to send information and server receives
[07:35] <Rabbi_Bob> Client -> Server: keeps going, server knows something is there however cannot communicate back
[07:35] <Rabbi_Bob> Server log: ERROR[ServerThread]: Server: peer_id=2: failed to emerge player
[07:36] <Rabbi_Bob> If I move the connection up to another port, it works
[07:36] <Rabbi_Bob> Server: >route -n
[07:36] <Rabbi_Bob> Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
[07:36] <Rabbi_Bob> 0.0.0.0         172.25.4.1      0.0.0.0         UG    100    0        0 eth4
[07:36] <Rabbi_Bob> 172.25.4.0      0.0.0.0         255.255.255.0   U     0      0        0 eth4
[07:36] <Rabbi_Bob> 172.25.4.0      0.0.0.0         255.255.255.0   U     0      0        0 eth1
[07:37] <Rabbi_Bob> eth4 is the working nic
[07:37] <Rabbi_Bob> eth1 is the failed to emerge nic
[07:37] <Rabbi_Bob> and it's the route out causing the issue

Does this fix your issue? Probably not and you'll have to figure out how your server is communicating on your network and how things are routing around to fix it. I haven't had time to look beyond getting it to work otherwise and may not bother. I suspect many people will have multiple NICs, especially wireless & wired combinations, and you may need to turn one off while troubleshooting in order to force everything down to one NIC.


For the search engines:

ERROR[ServerThread]: Server: peer_id=2: failed to emerge player
ERROR[ServerThread]: Server: peer_id=3: failed to emerge player
ERROR[ServerThread]: Server: peer_id=6: failed to emerge player

[madarexxx]

There is something with your server/client internet connection. try to compile latest minetest sources and restart server.

[RabbiBob]

There is something with your server/client internet connection. try to compile latest minetest sources and restart server.

No, there's something with the machine's routing not the Minetest server. You'll get the "failed to emerge player" error when the server attempts to talk back to the client and fails. The server knows the client is there because the client sends packets stating who it is (you'll see the player name on the server side coming inbound), it fails. The client will spin in a connecting state and the server will finally fail the connection on its end.

[BadWolf]

I run into this a lot, I'm running a Remobo server. sometimes people can log on quickly, other times it runs into this and the peer_id varies between 2 and 6. Usually the person retrys and it works, but it is annoying.