Hi, i connected 2 laptops (LAN). Both computer have network interface eth0. I installed also IBRDTN(IBR-DTN daemon 1.0.1 (build 294b543)) on both computers (via apt-get install in UBUNTU 14.04.2 LTS). I tested epidemic, flooding and prophet routing protocols root@vm1:/# dtnping dtn://vm2/echo ECHO dtn://vm2/echo 64 bytes of data. 64 bytes from dtn://vm2/echo: seq=1 ttl=30 time=36.39 ms 64 bytes from dtn://vm2/echo: seq=2 ttl=30 time=39.86 ms 64 bytes from dtn://vm2/echo: seq=3 ttl=30 time=43.78 ms 64 bytes from dtn://vm2/echo: seq=4 ttl=30 time=34.04 ms 64 bytes from dtn://vm2/echo: seq=5 ttl=30 time=40.22 ms and they work fine. Nevertheless, when i try to use UDP convergence layer by setting ibrdtnd.conf on both computers: net_interfaces = lan0 net_lan0_type = udp net_lan0_interface = eth0 net_lan0_port = 4556 ping does not work(neither dtnsend)! Ibrdtn daemon does not show any errors(see below). In wireshark i can only see Discovery packets. Moreover i can see that both nodes can see each other (by using ibrdtn api neighbor list command). Wed Dec 16 15:31:16 2015 INFO NativeDaemon: IBR-DTN daemon 1.0.1 (build 294b543) Wed Dec 16 15:31:16 2015 INFO Configuration: Configuration: /etc/ibrdtn/ibrdtnd.conf Wed Dec 16 15:31:16 2015 INFO NativeDaemon: use logfile for output: /var/log/ibrdtn/ibrdtn.log Wed Dec 16 15:31:16 2015 INFO NativeDaemon: Parallel event processing enabled using 4 processes. Wed Dec 16 15:31:16 2015 INFO BundleCore: Local node name: dtn://vm1 Wed Dec 16 15:31:16 2015 INFO BundleCore: Forwarding of bundles enabled. Wed Dec 16 15:31:16 2015 INFO NativeDaemon: using bundle storage in memory-only mode Wed Dec 16 15:31:16 2015 INFO NativeDaemon: API initialized using tcp socket: loopback:4550 Wed Dec 16 15:31:16 2015 INFO NativeDaemon: UDP ConvergenceLayer added on eth0:4556 Wed Dec 16 15:31:16 2015 INFO DiscoveryAgent: listen to [224.0.0.142]:4551 Wed Dec 16 15:31:16 2015 INFO DiscoveryAgent: listen to [ff02::142]:4551 Wed Dec 16 15:31:16 2015 INFO DiscoveryAgent: add interface eth0 Wed Dec 16 15:31:16 2015 INFO NativeDaemon: Using flooding routing extensions Wed Dec 16 15:31:16 2015 INFO FloodRoutingExtension: Initializing flooding routing module ibrdtn log looks the same on the second computer (except of course local node name:) Ubuntu instalation were made just before testing IBRDTN (ports are open, IPTABLES do not block anything, time on each computer differs by only 2 seconds) I would be very grateful if you could provide me with any hints or maybe someone experienced this issue and already know the solution for this problem. Best Regards Michał