When I try to ssh into localhost, it accepts the public key and immediately closes the connection. I've been going through pages of Google results for hours now with no progress. Here's what I get after ssh -v user@localhost:
OpenSSH_5.9p1, OpenSSL 0.9.8r 8 Feb 2011
debug1: Reading configuration data /Users/user/.ssh/config
debug1: Reading configuration data /etc/ssh_config
debug1: /etc/ssh_config line 20: Applying options for *
debug1: Connecting to localhost [::1] port 22.
debug1: Connection established.
debug1: identity file /Users/user/.ssh/id_rsa type -1
debug1: identity file /Users/user/.ssh/id_rsa-cert type -1
debug1: identity file /Users/user/.ssh/id_dsa type 2
debug1: identity file /Users/user/.ssh/id_dsa-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.9
debug1: match: OpenSSH_5.9 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.9
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Server host key: RSA 67:2f:0b:c8:40:e8:87:0f:57:ee:c7:68:ae:8a:5a:02
debug1: Host 'localhost' is known and matches the RSA host key.
debug1: Found key in /Users/user/.ssh/known_hosts:1
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,keyboard-interactive
debug1: Next authentication method: publickey
debug1: Trying private key: /Users/user/.ssh/id_rsa
debug1: Offering DSA public key: /Users/user/.ssh/id_dsa
debug1: Server accepts key: pkalg ssh-dss blen 433
debug1: read PEM private key done: type DSA
Connection closed by ::1
I'm running OSX 10.8, using ssh through Terminal.
Okay, so what finally worked was explicitly allowing connections from user. Setting System Prefs > Sharing > Remote Login > Allow access for: to All Users doesn't work; instead I had to check Only these users: and manually add all users. Hope this helps anyone else having the same problem.
A long time ago I had the same problem with Telnet, and if I remember it well, the problem was with the user having no home directory in /etc/passwd. I am assuming that you are trying to create a password-less connection, am I right? When you google it, there is a good explanation of it here: http://diuf.unifr.ch/main/tech/node/57 Also, here is an explanation how to quickly make the password less connection http://greg-n-blog.blogspot.com/search/label/scp
This worked for me in Cygwin using Windows within a large domain:
Add your Windows user ID to /etc/passwd. You can get it by typing $ mkpasswd -d | grep [username]. In a large domain, you may have to wait several hours.
Make sure the user ID given in /etc/passwd matches that in $ id -u, and the group ID matches that for Administrators in /etc/group
来源：https://stackoverflow.com/questions/12044958/ssh-localhost-closes-connection-after-successful-login