I have the current network configuration in my linux single board computer:
~# ifconfig
eth0 Link encap:Ethernet HWaddr 00:05:B7:EE:88:0A
inet addr:192.168.0.20 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::205:b7ff:feee:880a/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:258814 errors:0 dropped:0 overruns:0 frame:0
TX packets:358552 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:18117399 (17.2 MiB) TX bytes:122851279 (117.1 MiB)
Memory:d0400000-d047ffff
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:3380889 errors:0 dropped:0 overruns:0 frame:0
TX packets:3380889 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:956796465 (912.4 MiB) TX bytes:956796465 (912.4 MiB)
~# ip route
default via 192.168.0.1 dev eth0
192.168.0.0/24 dev eth0 proto kernel scope link src 192.168.0.20
239.255.42.21 dev eth0 scope link
The latter multicast route made my network unstable, meaning that, randomly i can no more reach any local network using unicast route, when having this problem I use this command to check from where the issue came:
print route get 192.168.0.x
and the result of this command is:
print route get 192.168.0.21
multicast 192.168.0.21 dev eth0 src 192.168.0.20
cache <mc>
However when I don't have this random issue, the same latter command shows:
ip route get 192.168.0.21
192.168.0.21 dev eth0 src 192.168.0.20
cache
I don't know how to troubleshoot this problem - I tried creating a TCP server on the other machine using netcat
, so when having the problem, I tried launching strace nc 192.168.0.21 12345
to show what happens and what I get is Network unreachable,
I used also tcpdump
to check what happens behind, but I do not see any useful information better then "Network Unreachable"
Any help please?