JSchException Algorithm negotiation fail

Question

I am trying to connect to remote sftp server over ssh with JSch  0 1 44-1  but during  session connect     I am getting this exception    com jcraft jsch JSchException  Algorithm negotiation fail at  com jcraft jsch Session receive kexinit Session java 529  at  com jcraft jsch Session connect Session java 291  at com jcraft jsch Session connect Session java 154         Logs from JSch   INFO  Connecting to xx xx xx xxport 22  INFO  Connection established  INFO  Remote version string  SSH-2 0-WeOnlyDo 2 0 6  INFO  Local version string  SSH-2 0-JSCH-0 1 44  INFO  CheckCiphers  aes256-ctr aes192-ctr aes128-ctr aes256-cbc aes192-cbc aes128-cbc 3des-ctr arcfour arcfour128 arcfour256 INFO  aes256-ctr is not available   INFO  aes192-ctr is not available  INFO  aes256-cbc is not available   INFO  aes192-cbc is not available  INFO  arcfour256 is not available   INFO  SSH MSG KEXINIT sent INFO  SSH MSG KEXINIT received  INFO  Disconnecting from xx xx xx xx port 22    I am able to log in to remote server with linux sftp command  I was trying to find any kind of clue in the internet but I failed   Debug output from linux sftp command   OpenSSH 5 5p1-DAM 1 2  OpenSSL 0 9 8r 8 Feb 201  debug1  Reading configuration data  etc DAM ssh ssh config debug1  Applying options for   debug1  Applying options for     debug1  Connecting to xx xx xx xx  xx xx xx xx  port 22  debug1  Connection established  debug1  identity file     spv id rsa key type -1 debug1  identity file     spv id rsa key-cert type -1 debug1  Remote protocol version 2 0  remote software version WeOnlyDo 2 0 6 debug1  no match  WeOnlyDo 2 0 6 debug1  Enabling compatibility mode for protocol 2 0 debug1  Local version string SSH-2 0-OpenSSH 5 5p1-DAM 1 2 debug1  SSH2 MSG KEXINIT sent debug1  SSH2 MSG KEXINIT received debug1  kex  server- gt client aes256-cbc hmac-md5 none debug1  kex  client- gt server aes256-cbc hmac-md5 none debug1  sending SSH2 MSG KEXDH INIT debug1  expecting SSH2 MSG KEXDH REPLY debug1  Host  xx xx xx xx  is known and matches the RSA host key  debug1  Found key in    ssh known hosts 8 debug1  ssh rsa verify  signature correct debug1  SSH2 MSG NEWKEYS sent debug1  expecting SSH2 MSG NEWKEYS debug1  SSH2 MSG NEWKEYS received debug1  Roaming not allowed by server debug1  SSH2 MSG SERVICE REQUEST sent debug1  SSH2 MSG SERVICE ACCEPT received debug1  Authentications that can continue  publickey debug1  Next authentication method  publickey debug1  Trying private key      spv id rsa key debug1  read PEM private key done  type RSA debug1  Authentication succeeded  publickey   debug1  channel 0  new  client-session  debug1  Entering interactive session  debug1  Sending subsystem  sftp Connected to xx xx xx xx  sftp gt

User · Accepted Answer

There are a couple of places that SSH clients and servers try and agree on a common implementation. Two I know of are encryption and compression. The server and client produce a list of available options and then the best available option in both lists is chosen.

If there is no acceptable option in the lists then it fails with the error you got. I'm guessing from the debug output here but it looks like the only server options for encryption are "aes256-cbc hmac-md5 none".

JSch doesn't do hmac-md5 and aes256-cbc is disabled because of your Java policy files. Two things you could try are...

To increase the available encryption libraries on the server, install unrestricted policy files on your client, enabling aes256-cbc (make sure the message saying it is disabled goes away, those policy files are notoriously easy to install on the wrong JVM) from the site:

For JDK 1.6: http://www.oracle.com/technetwork/java/javase/downloads/jce-6-download-429243.html

For JDK 1.7: http://www.oracle.com/technetwork/java/javase/downloads/jce-7-download-432124.html

For JDK 1.8: http://www.oracle.com/technetwork/java/javase/downloads/jce8-download-2133166.html
or try and disable encryption.

The first is ideal if you have access to the server (trust me aes128-cbc is plenty of encryption), but the second is easy enough to quickly test out the theory.

User · Answer

I updated jsch lib latest one  0 1 55   working fine for me  no need to restart the server or no need to update java current using java8

User · Answer

The issue is with the Version of JSCH jar you are using   Update it to latest jar   I was also getting the same error and this solution worked   You can download latest jar from  http   www jcraft com jsch

User · Answer

add KexAlgorithms   diffie-hellman-group1-sha1 diffie-hellman-group-exchange-sha  1 to   your sshd config on the server    This worked  but make sure you restart sshd  sudo service sshd restart

User · Answer

The solution for me was to install the oracle unlimited JCE and install in JRE HOME lib security  Then restarted glassfish and I was able to connect to my sftp server using jsch

User · Answer

The complete steps to add the algorithms to the RECEIVING server   the one you are connecting to   I m assuming this is a Linux server   sudo  etc ssh sshd config   Add this to the file  it can be at the end    KexAlgorithms curve25519-sha256 libssh org ecdh-sha2-nistp256 ecdh-sha2-nistp384 ecdh-sha2-nistp521 diffie-hellman-group-exchange-sha256 diffie-hellman-group14-sha1 diffie-hellman-group-exchange-sha1 diffie-hellman-group1-sha1   Then restart the SSH server   sudo service sshd restart

User · Answer

Make sure that you re using the latest version of JSch  I had this exact same problem when using JSch 0 1 31 and trying to connect to a RedHat 5 server  Updating to the latest version solved the problem

User · Answer

I had the same issue  running Netbeans 8 0 on Windows  and JRE 1 7   I just installed JRE 1 8 from https   www java com fr download   note that it s called Version 8 but it s version 1 8 when you install it   and it fixed it

User · Answer

FWIW  I had this same error message under JSch 0 1 50  Upgrading to 0 1 52 solved the problem

User · Answer

Finally a solution that works without having to make any changes to the server    Download the latest jsch jar as Yvan suggests  http   sourceforge net projects jsch files jsch jar  jsch-0 1 52 jar works fine Place the downloaded file in your      JetBrains PhpStorm 8 0 1 lib   and remove the existing jsch-file  for PHPStorm 8 it s jsch-0 1 50 jar  Restart PHPStorm and it should work   Use the same solution for Webstorm

[java] JSchException: Algorithm negotiation fail

Examples related to java

Examples related to encryption

Examples related to ssh

Examples related to sftp

Examples related to jsch