I habe a ZT network with two hosts, 10.147.19.1 and 10.147.19.213. When I start pinging one from the other, it takes a few seconds until I get a connection:
# ping 10.147.19.1
PING 10.147.19.1 (10.147.19.1) 56(84) bytes of data.
From 10.147.19.213 icmp_seq=10 Destination Host Unreachable
From 10.147.19.213 icmp_seq=11 Destination Host Unreachable
From 10.147.19.213 icmp_seq=12 Destination Host Unreachable
From 10.147.19.213 icmp_seq=13 Destination Host Unreachable
From 10.147.19.213 icmp_seq=14 Destination Host Unreachable
From 10.147.19.213 icmp_seq=15 Destination Host Unreachable
64 bytes from 10.147.19.1: icmp_seq=16 ttl=64 time=2058 ms
64 bytes from 10.147.19.1: icmp_seq=17 ttl=64 time=1034 ms
64 bytes from 10.147.19.1: icmp_seq=18 ttl=64 time=10.3 ms
64 bytes from 10.147.19.1: icmp_seq=19 ttl=64 time=6.32 ms
64 bytes from 10.147.19.1: icmp_seq=20 ttl=64 time=2.27 ms
64 bytes from 10.147.19.1: icmp_seq=21 ttl=64 time=3.12 ms
I’m guessing this is the time it takes to rebuild the VL1 tunnel after a NAT timeout?
Setting aside the question why this takes so long (I don’t suppose there’s a log of the steps performed behind the scenes?), my main question is:
Where does this “Destination Host Unreachable” come from? Who is sending that? I believe it is the reason why I frequently get “No route to host” errors on TCP connections.
The “Destination Host Unreachable” also takes a few seconds to appear, so there seems to be some kind of timeout? Like I start the ping, about 5 seconds go by, “Destination Host Unreachable” shows up, 5 more seconds go by, then finally I get ping replies.