I'm trying to connect to a SFTP host using vfs2 connector, which internally uses jsch. However, when I try to connect, I get the following exception:
12:50:31.747 INFO o.a.c.v.p.sftp.SftpClientFactory - Connecting to <host> port <port>
12:50:32.074 INFO o.a.c.v.p.sftp.SftpClientFactory - Connection established
12:50:32.376 INFO o.a.c.v.p.sftp.SftpClientFactory - Remote version string: SSH-2.0-OpenSSH_7.4
12:50:32.376 INFO o.a.c.v.p.sftp.SftpClientFactory - Local version string: SSH-2.0-JSCH-0.1.54
12:50:32.376 INFO o.a.c.v.p.sftp.SftpClientFactory - CheckCiphers: aes256-ctr,aes192-ctr,aes128-ctr,aes256-cbc,aes192-cbc,aes128-cbc,3des-ctr,arcfour,arcfour128,arcfour256
12:50:33.489 INFO o.a.c.v.p.sftp.SftpClientFactory - CheckKexes: diffie-hellman-group14-sha1,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521
12:50:34.192 INFO o.a.c.v.p.sftp.SftpClientFactory - CheckSignatures: ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
12:50:34.203 INFO o.a.c.v.p.sftp.SftpClientFactory - SSH_MSG_KEXINIT sent
12:50:34.203 INFO o.a.c.v.p.sftp.SftpClientFactory - SSH_MSG_KEXINIT received
12:50:34.203 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server: [email protected],diffie-hellman-group-exchange-sha256
12:50:34.203 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ssh-ed25519
12:50:34.203 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected],aes128-cbc,aes192-cbc,aes256-cbc,blowfish-cbc,cast128-cbc,3des-cbc
12:50:34.203 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected],aes128-cbc,aes192-cbc,aes256-cbc,blowfish-cbc,cast128-cbc,3des-cbc
12:50:34.203 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server: [email protected],[email protected],[email protected]
12:50:34.203 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server: [email protected],[email protected],[email protected]
12:50:34.203 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server: none,[email protected]
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server: none,[email protected]
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server:
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server:
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client: ssh-rsa,ssh-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client: aes128-ctr,aes128-cbc,3des-ctr,3des-cbc,blowfish-cbc,aes192-ctr,aes192-cbc,aes256-ctr,aes256-cbc
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client: aes128-ctr,aes128-cbc,3des-ctr,3des-cbc,blowfish-cbc,aes192-ctr,aes192-cbc,aes256-ctr,aes256-cbc
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client: hmac-md5,hmac-sha1,hmac-sha2-256,hmac-sha1-96,hmac-md5-96
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client: hmac-md5,hmac-sha1,hmac-sha2-256,hmac-sha1-96,hmac-md5-96
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client: none
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client: none
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client:
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client:
12:50:34.205 INFO o.a.c.v.p.sftp.SftpClientFactory - Disconnecting from <host> port <port>
12:50:34.243 ERROR c.s.saw.export.SFTPUploader - IO SFTP Error:
org.apache.commons.vfs2.FileSystemException: Could not connect to SFTP server at "sftp://<user>@<host>:<port>/".
at org.apache.commons.vfs2.provider.sftp.SftpFileProvider.createSession(SftpFileProvider.java:72)
at org.apache.commons.vfs2.provider.sftp.SftpFileProvider.doCreateFileSystem(SftpFileProvider.java:93)
at org.apache.commons.vfs2.provider.AbstractOriginatingFileProvider.getFileSystem(AbstractOriginatingFileProvider.java:93)
at org.apache.commons.vfs2.provider.AbstractOriginatingFileProvider.findFile(AbstractOriginatingFileProvider.java:72)
at org.apache.commons.vfs2.provider.AbstractOriginatingFileProvider.findFile(AbstractOriginatingFileProvider.java:56)
at org.apache.commons.vfs2.impl.DefaultFileSystemManager.resolveFile(DefaultFileSystemManager.java:717)
at org.apache.commons.vfs2.impl.DefaultFileSystemManager.resolveFile(DefaultFileSystemManager.java:654)
at com.synchronoss.saw.export.SFTPUploader.uploadFile(SFTPUploader.java:99)
at com.synchronoss.saw.export.SFTPUploader.main(SFTPUploader.java:134)
Caused by: org.apache.commons.vfs2.FileSystemException: Could not connect to SFTP server at "<host>".
at org.apache.commons.vfs2.provider.sftp.SftpClientFactory.createConnection(SftpClientFactory.java:163)
at org.apache.commons.vfs2.provider.sftp.SftpFileProvider.createSession(SftpFileProvider.java:65)
... 8 common frames omitted
Caused by: com.jcraft.jsch.JSchException: Algorithm negotiation fail
at com.jcraft.jsch.Session.receive_kexinit(Session.java:590)
at com.jcraft.jsch.Session.connect(Session.java:320)
at com.jcraft.jsch.Session.connect(Session.java:183)
at org.apache.commons.vfs2.provider.sftp.SftpClientFactory.createConnection(SftpClientFactory.java:161)
... 9 common frames omitted
I referred to a few blogs and stackoverflow links and tried multiple things. Still I'm not getting any successful result. Also, tried multiple versions of vfs2 and jsch with no avail.
Here are some of the links I referred:
JSchException: Algorithm negotiation fail
JSch Algorithm negotiation fail
https://dzone.com/articles/install-java-cryptography-extension-jce-unlimited
The cipher 'aes256-cbc' is required, but it is not available
Can someone please help me with this?
Your server supports only these MACs:
[email protected],[email protected],[email protected]
Those are not supported by JSch.
If you need to connect with JSch, you will have to configure your server to allow some MACs that JSch does support:
hmac-md5,hmac-sha1,hmac-sha2-256,hmac-sha1-96,hmac-md5-96
Use the MACs directive in sshd_config.
Though hmac-sha2-*[email protected] and hmac-sha2-* are possibly just aliases. So configuring JSch appropriately may help too:
config.put("[email protected]", "com.jcraft.jsch.jce.HMACSHA256");
But I'm not sure, if vfs2 interface allows such configuration.