Connection reset after Doing Diffie-Hellman group exchange

Hi,

I'm trying to allow access to a host using sftp. It is working fine from my system but not from the target system.

It says "Network error: Connection reset by peer" just after Doing Diffie-Hellman group exchange


The logs (with the real IP changed to a private one) are:

. 2007-03-08 11:55:48.290 WinSCP Version 3.8.2 (Build 330) (OS 5.1.2600 Service Pack 2)
. 2007-03-08 11:55:48.290 Login time: jueves, 08 de marzo de 2007 11:55:48
. 2007-03-08 11:55:48.290 --------------------------------------------------------------------------
. 2007-03-08 11:55:48.290 Session name: sroque@192.168.0.30
. 2007-03-08 11:55:48.290 Host name: 192.168.0.30 (Port: 22)
. 2007-03-08 11:55:48.290 User name: sroque (Password: Yes, Key file: No)
. 2007-03-08 11:55:48.290 Transfer Protocol: SFTP (SCP)
. 2007-03-08 11:55:48.290 SSH protocol version: 2; Compression: No
. 2007-03-08 11:55:48.290 Agent forwarding: No; TIS/CryptoCard: No; KI: Yes; GSSAPI: No
. 2007-03-08 11:55:48.290 Ciphers: aes,blowfish,3des,WARN,des; Ssh2DES: No
. 2007-03-08 11:55:48.290 Ping type: -, Ping interval: 30 sec; Timeout: 15 sec
. 2007-03-08 11:55:48.290 SSH Bugs: -,-,-,-,-,-,-,-
. 2007-03-08 11:55:48.290 SFTP Bugs: -,-,-
. 2007-03-08 11:55:48.290 Proxy: none
. 2007-03-08 11:55:48.290 Return code variable: Autodetect; Lookup user groups: Yes
. 2007-03-08 11:55:48.290 Shell: default, EOL: 0
. 2007-03-08 11:55:48.290 Local directory: default, Remote directory: home, Update: No, Cache: Yes
. 2007-03-08 11:55:48.290 Cache directory changes: Yes, Permanent: Yes
. 2007-03-08 11:55:48.290 Clear aliases: Yes, Unset nat.vars: Yes, Resolve symlinks: Yes
. 2007-03-08 11:55:48.290 Alias LS: No, Ign LS warn: Yes, Scp1 Comp: No
. 2007-03-08 11:55:48.290 --------------------------------------------------------------------------
. 2007-03-08 11:55:48.390 Looking up host "192.168.0.30"
. 2007-03-08 11:55:48.410 Connecting to 192.168.0.30 port 22
. 2007-03-08 11:55:48.530 Server version: SSH-2.0-OpenSSH_3.8.1p1 Debian-8.sarge.6
. 2007-03-08 11:55:48.540 We claim version: SSH-2.0-WinSCP_release_3.8.2
. 2007-03-08 11:55:48.550 Using SSH protocol version 2
. 2007-03-08 11:55:48.610 Doing Diffie-Hellman group exchange
. 2007-03-08 11:55:48.770 Network error: Connection reset by peer
* 2007-03-08 11:55:48.800 (ESshFatal) Network error: Connection reset by peer



Any idea of what is going on or a workarround?

Cheers
JD

Check the server's log to see why it closes the connection.

martin wrote:

Check the server's log to see why it closes the connection.

I don't see anything relevant, that is a connection attempt from the server side with debug3 enabled:

Mar 9 11:46:35 sms sshd[12426]: Connection from ::ffff:194.106.17.242 port 56505
Mar 9 11:46:35 sms sshd[10777]: debug1: Forked child 12426.
Mar 9 11:46:35 sms sshd[12426]: debug1: Client protocol version 2.0; client software version WinSCP_release_3.8.2
Mar 9 11:46:35 sms sshd[12426]: debug1: no match: WinSCP_release_3.8.2
Mar 9 11:46:35 sms sshd[12426]: debug1: Enabling compatibility mode for protocol 2.0
Mar 9 11:46:35 sms sshd[12426]: debug1: Local version string SSH-1.99-OpenSSH_3.8.1p1 Debian-8.sarge.6
Mar 9 11:46:35 sms sshd[12426]: debug2: Network child is on pid 12427
Mar 9 11:46:35 sms sshd[12426]: debug3: preauth child monitor started
Mar 9 11:46:35 sms sshd[12426]: debug3: mm_request_receive entering
Mar 9 11:46:35 sms sshd[12426]: debug3: monitor_read: checking request 0
Mar 9 11:46:35 sms sshd[12426]: debug3: mm_answer_moduli: got parameters: 1024 2048 8192
Mar 9 11:46:35 sms sshd[12426]: debug3: mm_request_send entering: type 1
Mar 9 11:46:35 sms sshd[12426]: debug2: monitor_read: 0 used once, disabling now
Mar 9 11:46:35 sms sshd[12426]: debug3: mm_request_receive entering
Mar 9 11:46:35 sms sshd[12426]: debug1: do_cleanup
Mar 9 11:46:57 sms sshd[10777]: Generating new 768 bit RSA key.
Mar 9 11:46:57 sms sshd[10777]: RSA key generation complete.

Can you connect with any other SSH client? It can also be a firewall issue.