更新到 Fedora 35 後，使用 ProxyCommand 的 SSH 失敗

我使用的命令如下所示：

ssh -o ProxyCommand='ncat --proxy-type socks5 --proxy 127.0.0.1:3744 %h %p' me@example.com

由於更新到 Fedora 35，連接失敗並顯示錯誤消息

kex_exchange_identification: Connection closed by remote host
Connection closed by UNKNOWN port 65535

我確認代理仍然可以通過 Web 瀏覽器使用。使用另一台電腦或在容器中使用 Fedora 34 與伺服器的連接仍然有效。在容器中使用 Fedora 35 時失敗。我還可以使用不同的伺服器重現結果。

詳細輸出似乎沒有幫助

OpenSSH_8.7p1, OpenSSL 1.1.1l  FIPS 24 Aug 2021
debug1: Reading configuration data /home/me/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Reading configuration data /etc/ssh/ssh_config.d/50-redhat.conf
debug1: Reading configuration data /etc/crypto-policies/back-ends/openssh.config
debug1: configuration requests final Match pass
debug1: re-parsing configuration
debug1: Reading configuration data /home/me/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Reading configuration data /etc/ssh/ssh_config.d/50-redhat.conf
debug1: Reading configuration data /etc/crypto-policies/back-ends/openssh.config
debug1: Executing proxy command: exec ncat -v --proxy-type socks5 --proxy 127.0.0.1:3744 example.com 22
debug1: identity file /home/me/.ssh/id_rsa type 0
debug1: identity file /home/me/.ssh/id_rsa-cert type -1
debug1: identity file /home/me/.ssh/id_dsa type -1
debug1: identity file /home/me/.ssh/id_dsa-cert type -1
debug1: identity file /home/me/.ssh/id_ecdsa type -1
debug1: identity file /home/me/.ssh/id_ecdsa-cert type -1
debug1: identity file /home/me/.ssh/id_ecdsa_sk type -1
debug1: identity file /home/me/.ssh/id_ecdsa_sk-cert type -1
debug1: identity file /home/me/.ssh/id_ed25519 type -1
debug1: identity file /home/me/.ssh/id_ed25519-cert type -1
debug1: identity file /home/me/.ssh/id_ed25519_sk type -1
debug1: identity file /home/me/.ssh/id_ed25519_sk-cert type -1
debug1: identity file /home/me/.ssh/id_xmss type -1
debug1: identity file /home/me/.ssh/id_xmss-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_8.7
Ncat: Version 7.91 ( https://nmap.org/ncat )
Ncat: Connected to proxy 127.0.0.1:3744
Ncat: No authentication needed.
Ncat: Host example.com will be resolved by the proxy.
Ncat: connection succeeded.
Ncat: 0 bytes sent, 0 bytes received in 0.04 seconds.
kex_exchange_identification: Connection closed by remote host
Connection closed by UNKNOWN port 65535

有同樣的問題。fedora 35 中的 nmap-ncat 似乎有些問題（即 nmap-ncat-7.91-8.fc35.x86_64）

作為一種解決方法，您可以使用 netcat-1.218-2.fc35.x86_64

或者直接安裝rpm -vhU https://nmap.org/dist/ncat-7.92-1.x86_64.rpm

來自https://nmap.org/download.html

引用自：https://serverfault.com/questions/1089364