Wireshark-users: Re: [Wireshark-users] Help with Output "TCP Dup ACK3#2 1320 > 22 ACK
Duplicate ACKs are fairly common, so they don't always
indicate a problem. During normal congestion you will receive duplicate ACKs if
the far end has not received a TCP segment it believes it should have. It also
can be used to keep alive a connection.
However if you get dup ACKs consistently at the start of a
connection it might mean that there is some sort of firewall ACL blocking
traffic. As Stephen said, it is important to know where this occurs during the 3
way handshake at the beginning of a connection or later on.
Martin Visser
Technology Consultant
Consulting &
Integration
Technology Solutions Group - HP Services
410 Concord
Road
Rhodes NSW 2138
Australia
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Hello, I am having a problem with SSH. I can ssh from some
server but not others. I verified that there are no access-lists blocking
from doing this. When I ran Wireshark on my pc and tried to ssh to the
server I get the following line that could be telling me what the problem is.
However, I don't understand it and was hoping some out there could explain it to
me. Here is the line:
[TCP Dup ACK 3#2] 1320 > 22 [ACK] Seq=1
Ack=1 win=65535 Len=0 Does this mean
anything to anyone? I'm guessing my problem lies here. If I ssh to a
server that works... I don't see this line Thanks Mike C.
