Unable to connect to SFTP

I have the following config in my sftp.json inside the .vscode folder:

{
  "protocol": "sftp",
  "host": "host.com",
  "port": 2222,
  "username": "username",
  "password": "pass"
}

But when I try to connect the connection is always getting timed out. On the other hand when I use the exact same details in FileZilla it works perfectly. In FileZilla after I connect, I get a popup like this which I need to accept in order to connect:

But there is no such thing in the vs code extension. Also previously when I used the liximomo version of the extension, I never had this issue. After I uninstalled that extension and installed this one, I can see this issue.

I have also enabled the SFTP log to see what’s going on and I see this in the log:

[07-08 14:08:37] [debug] Custom crypto binding not available
[07-08 14:08:37] [debug] Client: Trying ftp.sescollege.org on port 2222 ...
[07-08 14:08:37] [debug] Local ident: 'SSH-2.0-ssh2js1.1.0'
[07-08 14:08:38] [debug] Socket connected
[07-08 14:08:38] [debug] Remote ident: 'SSH-2.0-OpenSSH_5.3'
[07-08 14:08:38] [debug] Outbound: Sending KEXINIT
[07-08 14:08:38] [debug] Inbound: Handshake in progress
[07-08 14:08:38] [debug] Handshake: (local) KEX method: [e-mail],curve25519-sha256,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,diffie-hellman-group15-sha512,diffie-hellman-group16-sha512,diffie-hellman-group17-sha512,diffie-hellman-group18-sha512
[07-08 14:08:38] [debug] Handshake: (remote) KEX method: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
[07-08 14:08:38] [debug] Handshake: KEX algorithm: diffie-hellman-group-exchange-sha256
[07-08 14:08:38] [debug] Handshake: (local) Host key format: ssh-ed25519,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,rsa-sha2-512,rsa-sha2-256,ssh-rsa
[07-08 14:08:38] [debug] Handshake: (remote) Host key format: ssh-rsa,ssh-dss
[07-08 14:08:38] [debug] Handshake: Host key format: ssh-rsa
[07-08 14:08:38] [debug] Handshake: (local) C->S cipher: aes128-gcm,[e-mail],aes256-gcm,[e-mail],aes128-ctr,aes192-ctr,aes256-ctr,[e-mail]
[07-08 14:08:38] [debug] Handshake: (remote) C->S cipher: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[e-mail]
[07-08 14:08:38] [debug] Handshake: C->S Cipher: aes128-ctr
[07-08 14:08:38] [debug] Handshake: (local) S->C cipher: aes128-gcm,[e-mail],aes256-gcm,[e-mail],aes128-ctr,aes192-ctr,aes256-ctr,[e-mail]
[07-08 14:08:38] [debug] Handshake: (remote) S->C cipher: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[e-mail]
[07-08 14:08:38] [debug] Handshake: S->C cipher: aes128-ctr
[07-08 14:08:38] [debug] Handshake: (local) C->S MAC: [e-mail],[e-mail],[e-mail],hmac-sha2-256,hmac-sha2-512,hmac-sha1
[07-08 14:08:38] [debug] Handshake: (remote) C->S MAC: hmac-md5,hmac-sha1,[e-mail],hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,[e-mail],hmac-sha1-96,hmac-md5-96
[07-08 14:08:38] [debug] Handshake: C->S MAC: hmac-sha2-256
[07-08 14:08:38] [debug] Handshake: (local) S->C MAC: [e-mail],[e-mail],[e-mail],hmac-sha2-256,hmac-sha2-512,hmac-sha1
[07-08 14:08:38] [debug] Handshake: (remote) S->C MAC: hmac-md5,hmac-sha1,[e-mail],hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,[e-mail],hmac-sha1-96,hmac-md5-96
[07-08 14:08:38] [debug] Handshake: S->C MAC: hmac-sha2-256
[07-08 14:08:38] [debug] Handshake: (local) C->S compression: none,[e-mail],zlib
[07-08 14:08:38] [debug] Handshake: (remote) C->S compression: none,[e-mail]
[07-08 14:08:38] [debug] Handshake: C->S compression: none
[07-08 14:08:38] [debug] Handshake: (local) S->C compression: none,[e-mail],zlib
[07-08 14:08:38] [debug] Handshake: (remote) S->C compression: none,[e-mail]
[07-08 14:08:38] [debug] Handshake: S->C compression: none
[07-08 14:08:38] [debug] Outbound: Sending KEXDH_GEX_REQUEST
[07-08 14:08:38] [debug] Received DH GEX Group
[07-08 14:09:07] [debug] Outbound: Sending KEXDH_GEX_INIT
[07-08 14:09:07] [debug] Outbound: Sending DISCONNECT (11)
[07-08 14:09:07] [debug] Socket closed

Do you have any clue on how to resolve this matter so that I can use the extension?

[Mickeywaugh]

@Natizyskunk as your advise above, the algorithms configuration seems works with issue 1.15.2, good job! TKS!

[Natizyskunk]

@Mickeywaugh,

Can you try this please ?

FAQ : https://github.com/Natizyskunk/vscode-sftp/blob/master/FAQ.md#error-connection-closed

The problem would be that the SFTP extension keeps closing the connection for those who use more legacy/old systems. You’ll have to Explicitly override the default transport layer algorithms used for the connection to remove the new “diffie-hellman-group-exchange-sha256” algorithm that cause the problem from the kex section. Just add this in your sftp.json config file, which should make it work.

{
	...
	"host": "exemple.com",
	...
	"algorithms": {
		"kex": [
			"ecdh-sha2-nistp256", 
			"ecdh-sha2-nistp384", 
			"ecdh-sha2-nistp521", 
			"diffie-hellman-group14-sha1"
		],
		"cipher": [
			"aes128-ctr", 
			"aes192-ctr", 
			"aes256-ctr", 
			"aes128-gcm", 
			"[e-mail]", 
			"aes256-gcm", 
			"[e-mail]"
		],
		"serverHostKey": [
			"ssh-rsa", 
			"ecdsa-sha2-nistp256", 
			"ecdsa-sha2-nistp384", 
			"ecdsa-sha2-nistp521"
		],
		"hmac": [
			"hmac-sha2-256", 
			"hmac-sha2-512", 
			"hmac-sha1"
		]
	}
}

References: _Originally posted by @montorodiaz in https://github.com/liximomo/vscode-sftp/issues/883#issuecomment-783402096_ https://github.com/liximomo/vscode-sftp/wiki/SFTP-only-Config#sshcustomparams