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Wireshark-users: Re: [Wireshark-users] TCP Retransmission question

From: ronnie sahlberg <ronniesahlberg@xxxxxxxxx>
Date: Tue, 21 Jun 2011 18:02:30 +1000
On Tue, Jun 21, 2011 at 5:46 PM, Thomas Anderson
<t.dt.aanderson@xxxxxxxxx> wrote:
> I have two virtual machines running on virtualbox whose os is debian.
> Currently my connection using ssh from A(xxx.xxx.xxx.111) to
> B(xxx.xxx.xxx.112) sometimes suffers the connection timeout. So I use
> wireshark (with filter `host xxx.xxx.xxx.112') to check the underlying
> network packets and notice sometimes it seems the ssh will do TCP
> retransmission as below:
>
> xxx.xxx.xxx.112 68.168.113.155  SSH     [TCP Retransmission] Encrypted
> response packet len=35
> 68.168.113.155  xxx.xxx.xxx.112 TCP     [TCP Previous segment lost] 33514 >
> ssh [ACK] Seq=21 Ack=36 Win=5888 Len=0 TSV=3950744190 TSER=4316095
> SLE=1 SRE=36
> 68.168.113.155  xxx.xxx.xxx.112 SSHv2   [TCP Retransmission] Client
> Protocol: SSH-2.0-libssh-0.1\r
>
> However, the ip address started with 68 is not any machine I know of.
> Does it mean my ssh may be compromised? Or what key word I can filter
> to find out the root cause (that ssh connection timeout)?

Doesnt look good.
Someone has established a live SSH connection to your box.

Probably not good at all.

>
> Thanks.
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