Lan_Use_Tcp: What Is "lan"?

[goli]

Hey there.

 

 

I have a strange problem with routing/firewalling that will be resolved with using TCP immediately.

 

If you don't want to read my problem: Just skip this section. The actual question will come later.

 

My network setup:

• Computer 1 is in "private lan", has IP 192.168.0.100/24 and runs btsync on port 1111
• Computer 2 is in "DMZ", has IP 192.168.1.100/24 and runs btsync on port 2222
• Computer 1 and Computer 2 are connecte through an OpenWRT router (192.168.0.1 and 192.168.1.1), that allows full access from "private lan" to "DMZ" but access from "DMZ" to "private lan" only for established connections.
• A third Computer 3 is something completely different. It is located at a datacenter, has a unique, public, fully routed and not-firewalled IP address, running btsync on port 3333
• All tests are done with only two of those computers running, the other has temporarily disabled btsync instances to not cross-influence.

 

The btsync connectivity:

• All three computers do see each other.
• Only write secrets.
• No relays allowed at all.
• When adjusting a file on Computer 3, it gets replicated to both, Computer 1 and Computer 2
• When adjusting a file on Computer 2, it gets replicated to both, Computer 1 and Computer 3.
• When adjusting a file on Computer 1, it gets replicated only to Computer 3, but not to Computer 2
• The error message in debug log: "Blocked downloading file due Connection closed".

 

When adding a static allow rule to my OpenWRT that accepts connections from 192.168.1.100 to 192.168.0.100:1111, replication starts from 1o to 2, too.

 

This sithatuion must be a result of ugly OpenWRT iptables connection tracking, but that's something I cannot change at the moment.

 

Here's the question:

 

How does btsync determine "lan" for the setting "lan_use_tcp"?

 

My network setup (at least the part showing issues) doesn't involve WAN but only LAN, although there is routing and the conflicting nodes aren't on the same subnet.

 

Maybe I could make btsync realize that it's LAN and to use TCP only here?

 

 

Regards,

Stephan.