[solved]No route to host Problem


i have the following problem with syncing a repository with another node. I use syncthing v0.8.16 for x86_64 on two linux machines.

The node is detected, but the route can’t be established. Therefore the node is marked as “Disconnected” in the Web-Gui.

The output from STTRACE=net ./syncthing is the following:

  main.go:645: DEBUG: dial AAAA ipAdress:21035
  main.go:650: DEBUG: dial tcp ipAdress:21035: no route to host

Both nodes are in the same local network, and the resolution from the AAAA node to the correct ip-address is done well, so i don’t know where the problem is.

I would thank you for every idea for solving that problem.

What’s the actual log output, without obfuscated IP address (nor node ID, it’s not sensitive) and output from netstat -rn and ping <that ip address>? Barring weird bugs, the error should mean that the IP address in question is not reachable.


i first also thought that their is perhaps a problem, but i can ping the ip-adress without problem. Here the result of netstat -rn:

Ziel      Router     Genmask        Flags   MSS  Fenster irtt Iface         UG        0 0         0 eth0   U         0 0         0 eth0

Ping to works fine. Here the logoutput:

[F5ANX] 2014/06/25 10:38:51.526937 main.go:187: INFO: syncthing v0.8.16 (go1.3 linux-amd64 default) jb@jborg-mbp 2014-06-22 16:18:21 UTC
[F5ANX] 2014/06/25 10:38:51.527494 main.go:188: INFO: My ID: F5ANXPRXA5OWBVLWIDEIACW3MY3KUGTCNLMS3QFRM7KI647IHIEQ
[F5ANX] 2014/06/25 10:38:51.530695 main.go:331: INFO: Starting web GUI on
[F5ANX] 2014/06/25 10:38:52.195219 main.go:345: INFO: Populating repository index
[F5ANX] 2014/06/25 10:38:52.202134 main.go:715: INFO: Sending local discovery announcements
[F5ANX] 2014/06/25 10:38:52.202336 main.go:398: OK: Ready to synchronize default (read-write)
[F5ANX] 2014/06/25 10:38:52.202461 main.go:414: INFO: Node 7BLTXOK732FMRG35P4BPPF4WGHMWTOQJCOSMH6UIIYZMKMSQOZTA is "Pangun" at [dynamic]
[F5ANX] 2014/06/25 10:38:52.202543 main.go:414: INFO: Node F5ANXPRXA5OWBVLWIDEIACW3MY3KUGTCNLMS3QFRM7KI647IHIEQ is "Samba" at []
[F5ANX] 2014/06/25 10:38:52.203026 main.go:578: DEBUG: listening on
[F5ANX] 2014/06/25 10:39:07.204739 main.go:645: DEBUG: dial 7BLTXOK732FMRG35P4BPPF4WGHMWTOQJCOSMH6UIIYZMKMSQOZTA
[F5ANX] 2014/06/25 10:39:07.205949 main.go:650: DEBUG: dial tcp no route to host

The two last lines like in the above posting repeat themselves. I hope that helps for locating the problem.

Nothing obvious jumps out. Did you set the listen port to 21035 manually on Does a telnet connect? Any firewall on that host that might need tweaking?


thanks for the Idea with the firewall. I forgot that one system is a fedorea linux. So first i thought selinux is getting in the way, but in the end it was like you expected the firewall(iptables) which don’t let the traffic through. Thanks

A modification of the lines at the end of the issue “Syncthing failing to find other nodes” helps.

Sorry for disturbing with an beginners failure and thanks again.