MobaXterm通过DNS解析IPv6连接服务器时出现卡顿无响应问题

看起来你碰到了个挺让人头疼的MobaXterm连接问题，我先帮你把目前的情况理清楚：

正常连接的场景 #

• 用IPv4连接服务器时，不管是通过DNS解析还是直接用IP，连接过程都很顺畅
• 直接用IPv6地址（不通过DNS）连接时，也没有任何问题

出现卡顿的异常场景 #

当你同时使用DNS和IPv6连接服务器时，MobaXterm在显示完服务器的横幅提示后，会突然卡住、无响应好几秒，之后才能正常进入shell界面。

PowerShell测试的对比结果 #

有意思的是，用PowerShell测试同样的DNS+IPv6连接时，完全没有出现这种延迟，以下是PowerShell里的SSH调试日志：

debug1: kex_input_ext_info: server-sig-algs=<ssh-ed25519,sk-ssh-ed25519@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,sk-ecdsa-sha2-nistp256@openssh.com,webauthn-sk-ecdsa-sha2-nistp256@openssh.com,ssh-dss,ssh-rsa,rsa-sha2-256,rsa-sha2-512>
debug1: kex_input_ext_info: publickey-hostbound@openssh.com (unrecognised)
debug1: SSH2_MSG_SERVICE_ACCEPT received

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Authorized access only!
If you are not authorized to access or use this system, disconnect now!
All actions will be logged and unauthorized access could be legally pursued!

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debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Trying private key: C:\\Users\\Jean\\.ssh\\id_server
debug1: read_passphrase: can't open /dev/tty: No such file or directory
Enter passphrase for key 'C:\\Users\\Jean\\.ssh\\id_server':
debug1: Authentication succeeded (publickey).
Authenticated to xxxxxx.com ([2xxxx:xxxxxxxx]:22).
debug1: channel 0: new [client-session]
debug1: Requesting no-more-sessions@openssh.com
debug1: Entering interactive session.
debug1: pledge: network
debug1: ENABLE_VIRTUAL_TERMINAL_INPUT is supported. Reading the VTSequence from console
debug1: ENABLE_VIRTUAL_TERMINAL_PROCESSING is supported. Console supports the ansi parsing
debug1: client_input_global_request: rtype hostkeys-00@openssh.com want_reply 0
debug1: Remote: /home/jean/.ssh/authorized_keys:4: key options: agent-forwarding port-forwarding pty user-rc x11-forwarding
Linux server 6.1.21-v7+ #1642 SMP Mon Apr  3 17:20:52 BST 2023

备注：内容来源于stack exchange，提问作者JoelCrypto