Connection closed by ::1 error in cygwin

Question

I am trying to do ssh connection using cygwin. I have followed instructions given here. When I fire ssh localhost command I get Connection closed by ::1 error. As I am newbie to unix and cygwin, I am not able to figure out what has gone wrong. Please can anyone tell me why this error comes and how to resolve it?

My cygwin shell looks as follows :

$ ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/home/Shekhar/.ssh/id_rsa):
/home/Shekhar/.ssh/id_rsa already exists.
Overwrite (y/n)? y
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/Shekhar/.ssh/id_rsa.
Your public key has been saved in /home/Shekhar/.ssh/id_rsa.pub.
The key fingerprint is:
85:69:77:cc:fd:21:8a:ce:fe:46:41:ee:c8:e7:3d:7b Shekhar@Shekhar-PC
The key's randomart image is:
+--[ RSA 2048]----+
|                 |
|         o + .   |
|        + = +... |
|       . o.+. ...|
|        S.o..   .|
|        oo +     |
|         o+ .    |
|        .  o o E |
|         .o. .+  |
+-----------------+

Shekhar@Shekhar-PC ~
$ cd ~/.ssh/

Shekhar@Shekhar-PC ~/.ssh
$ ls -l
total 10
-rw-r--r-- 1 Shekhar None 1200 Jun 16 19:49 authorized_keys
-rw------- 1 Shekhar None 1675 Jun 20 08:55 id_rsa
-rw-r--r-- 1 Shekhar None  400 Jun 20 08:55 id_rsa.pub
-rw-r--r-- 1 Shekhar None  171 Jun  6 23:28 known_hosts

Shekhar@Shekhar-PC ~/.ssh
$ cat id_rsa.pub >> authorized_keys

Shekhar@Shekhar-PC ~/.ssh
$ ssh localhost
Connection closed by ::1

Solution 1

My problem is solved. I just removed cygwin and re-installed it and somehow its working properly now.

Solution 2

I experienced this same issue. The problem for me at least, was the creation of the cyg_server user using the ssh-host-config. It was created without a home directory and with it's shell set to /bin/false. So, I altered the /etc/passwd file for the cyg_server user to reflect /home/cyg_server (changed from /var/empty) and /bin/false to /bin/bash and created the home directory for the user. Tried to reconnect using the cyg_server user and voila.

in short:

mkdir /home/cyg_server
vim /etc/passwd
cyg_server:...(bunch of stuff)...:/var/empty:/bin/false

to

cyg_server:...(bunch of stuff)...:/home/cyg_server:/bin/bash

Presumably cygwin has a usermod command or synonym that would do this a little safer. But I was impatient and this is what I did. If anyone follows this please note to be extremely careful when editing the /etc/passwd file.

Solution 3

Just in case other find the same problem. Since you selected the cyg_server as user name while configuring ssh try to connect as using "ssh cyg_server@localhost" command rather than the default "ssh localhost". The password can be same as what you provided while configuring

Solution 4

Putting this here in case someone runs into this later. I had the same problem and reinstalling cygwin solved it... until I rebooted. Then I got the same error again. I now resolved the problem for the second time: instead of using the account name "cyg_server" that cygwin suggests to me when running ssh-host-config, I entered the name of my normal admin account on windows. Seems to be working so far.

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Comments

[Pragmateek]

Thanks a lot Sabosan for your answer: this solved my issue too +1 :)

[Shekhar]

can anyone explain reason for downvoting?

[sushain97]

+1. Worked perfectly.

[kakyo]

I had to do these to fix Op's problem: chown <USERNAME> /var/log/sshd.log chown -R <USERNAME> /var/empty chown <USERNAME> /etc/ssh* chmod 755 /var/empty chmod 644 /var/log/sshd.log

[James Selvakumar]

I found the ownership of /var/empty correctly set to cyg_server:Root. So I didn't change the home directory of cyg_server. Instead I changed only the shell from /bin/false to /bin/bash and it worked perfectly. Another thing is that users should ensure that cygwin batch file is run with administrator privileges. Many thanks.

[Shailendra]

I followed the suggestions and logged in using cyg_server and it worked like a charm ! Thanks !

[Admin]

Because reinstalling OS on a minor issue is not a good advice

[Shekhar]

Please read answer carefully before down voting. I reinstalled Cygwin, I didn't reinstalled OS.

[Admin]

Yeah but you reinstalled cygwin. It is not a very good advice. I used OS just to give an example.