SSHエージェント転送が機能していません

SSHエージェント転送が機能しません。答えからこの質問はかなり古いですし、その答えは、コメントと競合しています。最新の回答をお願いできますか？

基本的に、コンピューターAからコンピューターB、またはコンピューターAからコンピューターCにSSHで接続できますが、コンピューターAからコンピューターB、そしてコンピューターBからコンピューターCにSSH接続することはできません。ssh -ASSHエージェント転送を強制するために使用します。しかし、パスフレーズを要求されない限り、コンピューターA->コンピューターB->コンピューターCを接続することはできません。

echo "$SSH_AUTH_SOCK"サーバーとローカルマシンの両方で動作しますが、A-> BからのSSHでは、次のようになりssh-add -lます：

エージェントにはIDがありません。

一方、Aには2つのキーがリストされています。

すべての3台のマシンは何も変更せずに、標準のUbuntuのSSH構成の内容で構成されている/etc/ssh/ssh_configし、/etc/ssh/sshd_configに掲載されているhttp://paste.ubuntu.com/11482964/。

編集：リクエストに応じて、

-AvvvBからCのログは次のとおりです。

OpenSSH_6.2p2 Ubuntu-6ubuntu0.1, OpenSSL 1.0.1e 11 Feb 2013
debug1: Reading configuration data /home/myid/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to boxc.
debug1: Connection established.
debug3: Incorrect RSA1 identifier
debug3: Could not load "/home/myid/.ssh/id_rsa" as a RSA1 public key
debug1: identity file /home/myid/.ssh/id_rsa type 1
debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-1024
debug1: Checking blacklist file /etc/ssh/blacklist.RSA-1024
debug1: identity file /home/myid/.ssh/id_rsa-cert type -1
debug3: Incorrect RSA1 identifier
debug3: Could not load "/home/myid/.ssh/id_dsa" as a RSA1 public key
debug1: identity file /home/myid/.ssh/id_dsa type 2
debug1: Checking blacklist file /usr/share/ssh/blacklist.DSA-1024
debug1: Checking blacklist file /etc/ssh/blacklist.DSA-1024
debug1: identity file /home/myid/.ssh/id_dsa-cert type -1
debug1: identity file /home/myid/.ssh/id_ecdsa type -1
debug1: identity file /home/myid/.ssh/id_ecdsa-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.2p2 Ubuntu-6ubuntu0.1
debug1: Remote protocol version 2.0, remote software version OpenSSH_6.2p2 Ubuntu-6
debug1: match: OpenSSH_6.2p2 Ubuntu-6 pat OpenSSH*
debug2: fd 3 setting O_NONBLOCK
debug3: put_host_port: boxc
debug3: load_hostkeys: loading entries for host "boxc" from file "/home/myid/.ssh/known_hosts"
debug3: load_hostkeys: found key type RSA in file /home/myid/.ssh/known_hosts:15
debug3: load_hostkeys: loaded 1 keys
debug3: order_hostkeyalgs: prefer hostkeyalgs: ssh-rsa-cert-v01@openssh.com,ssh-rsa-cert-v00@openssh.com,ssh-rsa
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa-cert-v01@openssh.com,ssh-rsa-cert-v00@openssh.com,ssh-rsa,ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ssh-dss-cert-v01@openssh.com,ssh-dss-cert-v00@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-dss
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: hmac-md5-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-ripemd160-etm@openssh.com,hmac-sha1-96-etm@openssh.com,hmac-md5-96-etm@openssh.com,hmac-md5,hmac-sha1,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-ripemd160-etm@openssh.com,hmac-sha1-96-etm@openssh.com,hmac-md5-96-etm@openssh.com,hmac-md5,hmac-sha1,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: zlib@openssh.com,zlib,none
debug2: kex_parse_kexinit: zlib@openssh.com,zlib,none
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: first_kex_follows 0 
debug2: kex_parse_kexinit: reserved 0 
debug2: kex_parse_kexinit: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: hmac-md5-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-ripemd160-etm@openssh.com,hmac-sha1-96-etm@openssh.com,hmac-md5-96-etm@openssh.com,hmac-md5,hmac-sha1,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-ripemd160-etm@openssh.com,hmac-sha1-96-etm@openssh.com,hmac-md5-96-etm@openssh.com,hmac-md5,hmac-sha1,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib@openssh.com
debug2: kex_parse_kexinit: none,zlib@openssh.com
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: first_kex_follows 0 
debug2: kex_parse_kexinit: reserved 0 
debug2: mac_setup: found hmac-md5-etm@openssh.com
debug1: kex: server->client aes128-ctr hmac-md5-etm@openssh.com zlib@openssh.com
debug2: mac_setup: found hmac-md5-etm@openssh.com
debug1: kex: client->server aes128-ctr hmac-md5-etm@openssh.com zlib@openssh.com
debug1: sending SSH2_MSG_KEX_ECDH_INIT
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: RSA ed:26:20:93:4c:88:ef:17:70:e3:d4:7a:42:4c:8e:69
debug3: put_host_port: [192.168.2.122]:21
debug3: put_host_port: boxc
debug3: load_hostkeys: loading entries for host "boxc" from file "/home/myid/.ssh/known_hosts"
debug3: load_hostkeys: found key type RSA in file /home/myid/.ssh/known_hosts:15
debug3: load_hostkeys: loaded 1 keys
debug3: load_hostkeys: loading entries from file "/home/myid/.ssh/known_hosts"
debug3: load_hostkeys: found key type RSA in file /home/myid/.ssh/known_hosts:16
debug3: load_hostkeys: loaded 1 keys
debug1: Host 'boxc' is known and matches the RSA host key.
debug1: Found key in /home/myid/.ssh/known_hosts:15
debug1: ssh_rsa_verify: signature correct
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /home/myid/.ssh/id_rsa (0x7f7e....e760),
debug2: key: /home/myid/.ssh/id_dsa (0x7f7e....e7a0),
debug2: key: /home/myid/.ssh/id_ecdsa ((nil)),
debug1: Authentications that can continue: publickey
debug3: start over, passed a different list publickey
debug3: preferred gssapi-keyex,gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /home/myid/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Server accepts key: pkalg ssh-rsa blen 149
debug2: input_userauth_pk_ok: fp 22:32:...:1d:e3
debug3: sign_and_send_pubkey: RSA 22:32:...:1d:e3
debug1: key_parse_private_pem: PEM_read_PrivateKey failed
debug1: read PEM private key done: type <unknown>
Enter passphrase for key '/home/myid/.ssh/id_rsa':