long ssh handshake

[realdreams]

In one network environment ssh handshake takes like 30s for securecrt, no problem for putty

packet capture shows that
tcp handshake
client protocol
server protocol
both side ack
server key init
client ack
16.5s nothing
client key init
client dh init
etc....

So why does securecrt waits so long to send client key init? It only happens in one network environment. server fingerprint is verified. I tested at other places with private IP but can't repro this problem

Thanks