在按预期工作数月后，服务器护林员昨天刚刚在 ssh 登录时变得无响应。身份验证成功，但随后-vvv日志显示为会话建立的通道上设置了难以置信的长延迟：
debug1: Authentication succeeded (publickey).
Authenticated to ranger ([192.168.1.115]:22).
debug1: channel 0: new [client-session]
debug3: ssh_session2_open: channel_new: 0
debug2: channel 0: send open
debug3: send packet: type 90
debug1: Requesting no-more-sessions@openssh.com
debug3: send packet: type 80
debug1: Entering interactive session.
debug1: pledge: network
debug3: receive packet: type 80
debug1: client_input_global_request: rtype hostkeys-00@openssh.com want_reply 0
debug3: receive packet: type 91
debug2: callback start
debug2: fd 3 setting TCP_NODELAY
debug3: ssh_packet_set_tos: set IP_TOS 0x10
debug2: client_session2_setup: …