Under review

"Failed initialization" error, SFTP

9 years ago in iPad • updated by 7 years ago • 4

application server output "fatal: Unable to negotiate a key exchange method [preauth]"
OpenSSH_6.6.1p1 Ubuntu-8, OpenSSL 1.0.1f 6 Jan 2014
Ubuntu 14.10

connection with other clients is possible, but textastic returns an error

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Under review

9 years ago

I haven't heard of such a problem before. Does your server maybe limit the supported authentication methods?

Please try to enable the "Debug Log" setting in the connection's settings screen. Tap on the (i) button on the right side of a connection to change its settings. This creates a log file when you try to connect to the server which might help you find out what's wrong.

9 years ago

Hostname was NOT found in DNS cache
Trying 141.22.30.79 ...
Connected to sftp.informatik.haw-hamburg.de (141.22.30.79) port 22
Failure establishing ssh session
Closing connection

its an education server and i asked the developer, and he told me everything is fine and works. We can't find the fault. For example it's possible to connect with other tools (FileZilla) to the server and it works.

7 years ago

I have a similar problem.

I'm trying to connect to my ssh server on a raspberry pi with OpenSSH 7.5

Get this error in the Textastic Log:

== Info: Trying 192.168.2.25...
== Info: TCP_NODELAY set
== Info: Connected to 192.168.2.25 (192.168.2.25) port 22 (#0)
== Info: Failure establishing ssh session
== Info: Closing connection 0

And this on the server side:

Connection from 192.168.2.15 port 49722 on 192.168.2.25 port 22
Unable to negotiate with 192.168.2.15 port 49722: no matching key exchange method found.
Their offer: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 [preauth]

Connection from other clients works fine.

I can set a "compatibility_mode" on my server and than it works, but its less secure.

7 years ago

Hello,

Textastic uses libssh2. The latest version of libssh2 supports the following key exchange methods: diffie-hellman-group1-sha1, diffie-hellman-group14-sha1, diffie-hellman-group-exchange-sha1, diffie-hellman-group-exchange-sha256 (see https://www.libssh2.org)

If your server doesn't accept one of these, Textastic cannot connect, sorry.

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