通過中間主機的 SSH 僅在 myuser@mymac 上失敗，但在其他地方有效

我無法在我的 macbook 上使用我的使用者通過 ssh 連接到我的數據中心節點之一。這是一個最近出現的問題，從幾週前開始就非常實用。

奇怪的是，這只會影響我電腦上的使用者，但我能夠從以下位置建立連接：

• 同一台機器上的不同使用者，使用相同的 ssh 密鑰並且沒有任何 .ssh/config 規則。
• 不同的伺服器，執行 macos 或 ubuntu，具有相同或不同的 ssh 密鑰。

在我的電腦中使用我的使用者名和相同的密鑰，我可以：

• 連接到網關主機
• 使用 VPN 直接連接到節點（不幸的是，這不是一個長期的解決方案）

我對這個錯誤感到很困惑。你能幫我定位問題嗎？

查看日誌，與網關的連接已建立，但無法連接到節點。在客戶端：

⌘ ~ ❯ ssh -v -J gatekeeper@gateway ubuntu@node -i ~/.ssh/id_rsa 
OpenSSH_7.3p1, LibreSSL 2.4.1
[...]
debug1: Authentication succeeded (publickey).
Authenticated to gateway ([35.156.248.245]:22).
debug1: channel_connect_stdio_fwd node:22
debug1: channel 0: new [stdio-forward]
debug1: getpeername failed: Bad file descriptor
debug1: Requesting no-more-sessions@openssh.com
debug1: Entering interactive session.
debug1: pledge: network
debug1: client_input_global_request: rtype keepalive@openssh.com want_reply 1
debug1: client_input_global_request: rtype keepalive@openssh.com want_reply 1
debug1: client_input_global_request: rtype keepalive@openssh.com want_reply 1
debug1: client_input_global_request: rtype keepalive@openssh.com want_reply 1
debug1: client_input_global_request: rtype keepalive@openssh.com want_reply 1
debug1: client_input_global_request: rtype keepalive@openssh.com want_reply 1
debug1: client_input_global_request: rtype keepalive@openssh.com want_reply 1
debug1: client_input_global_request: rtype keepalive@openssh.com want_reply 1
channel 0: open failed: connect failed: Connection timed out
stdio forwarding failed
ssh_exchange_identification: Connection closed by remote host

在網關端：

admin@gateway:~$ grep -e "\[7669\]" -e "\[7739\]" /var/log/auth.log
Mar 13 11:01:20 gateway sshd[7669]: Set /proc/self/oom_score_adj to 0
Mar 13 11:01:20 gateway sshd[7669]: rexec line 32: Deprecated option PermitBlacklistedKeys
Mar 13 11:01:20 gateway sshd[7669]: Connection from <laptop-out-ip> port 62113 on <gateway-ip> port 22
Mar 13 11:01:20 gateway sshd[7669]: Postponed publickey for gatekeeper from <laptop-out-ip> port 62113 ssh2 [preauth]
Mar 13 11:01:20 gateway sshd[7669]: Accepted publickey for gatekeeper from <laptop-out-ip> port 62113 ssh2: RSA 8d:7e:9c:53:11:c9:4d:b3:67:7b:ae:04:03:8f:e2:71
Mar 13 11:01:20 gateway sshd[7669]: pam_unix(sshd:session): session opened for user gatekeeper by (uid=0)
Mar 13 11:01:20 gateway sshd[7669]: User child is on pid 7739
Mar 13 11:03:27 gateway sshd[7739]: error: connect_to <node-ip> port 22: failed.
Mar 13 11:03:28 gateway sshd[7739]: Connection closed by <laptop-out-ip>
Mar 13 11:03:28 gateway sshd[7739]: Transferred: sent 2252, received 2864 bytes
Mar 13 11:03:28 gateway sshd[7739]: Closing connection to <laptop-out-ip> port 62113
Mar 13 11:03:28 gateway sshd[7669]: pam_unix(sshd:session): session closed for user gatekeeper

在節點端，日誌中沒有條目。

網關上的 ssd_config：

# ssh service configuration

AcceptEnv
AddressFamily inet
AllowAgentForwarding yes
AllowGroups
AllowTcpForwarding no
AllowUsers gatekeeper
AuthorizedKeysFile %h/.ssh/authorized_keys
ChallengeResponseAuthentication no
Ciphers aes128-ctr,aes192-ctr,aes256-ctr
ClientAliveCountMax 3
ClientAliveInterval 15
Compression delayed
DenyGroups
DenyUsers
GSSAPIAuthentication no
GatewayPorts no
HostKey /etc/ssh/ssh_host_dsa_key
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_ecdsa_key
HostbasedAuthentication no
KerberosAuthentication no
ListenAddress 0.0.0.0:22
LogLevel VERBOSE
LoginGraceTime 60
MaxAuthTries 6
MaxSessions 10
MaxStartups 30
PasswordAuthentication no
PermitBlacklistedKeys no
PermitRootLogin no
PermitTunnel no
PermitUserEnvironment no
PidFile /var/run/sshd.pid
PrintLastLog yes
PrintMotd no
Protocol 2
PubkeyAuthentication yes
RSAAuthentication no
RhostsRSAAuthentication no
StrictModes yes
SyslogFacility AUTH
TCPKeepAlive yes
UseDNS no
UseLogin no
UsePAM yes
UsePrivilegeSeparation yes
X11Forwarding no

Match User gatekeeper
AllowTcpForwarding yes
AllowAgentForwarding no
X11Forwarding no

最後，我已經能夠解決問題並確定問題的根源。我可以通過不採購 iterm2 shell 集成來使問題消失，或者只是將其更新到最新版本。這可能與使用fish shell有關。

我沒有深入研究這個問題，如果有人感興趣，請告訴我。

error: connect_to <node-ip> port 22: failed.

這看起來像埠轉發被配置中的PermitOpen選項禁用或限制sshd。確保允許，如果不允許，請發布sshd_configfrom gateway。

引用自：https://serverfault.com/questions/837926