ssh connection refused

ssh: connect to host localhost port 22: Connection refused

問題

在使用ssh連接時出現：

$ ssh localhost
ssh: connect to host localhost port 22: Connection refused

分析

SSH是否開啟，端口是否監聽

檢查端口是否監聽

$ ss -tnlp
State     Recv-Q      Send-Q            Local Address:Port             Peer Address:Port

從命令結果可以看到，SSH的監聽端口(22)並沒有

檢查sshd.service服務是否開啟

$ systemctl status sshd.service
● sshd.service - OpenSSH Daemon
   Loaded: loaded (/usr/lib/systemd/system/sshd.service; disabled; vendor preset: disabled)
   Active: inactive (dead)

sshd.service沒有沒有激活

原因

ssh服務沒有啟動，端口未處於監聽狀態

解決

$ systemctl start sshd.service
$ systemctl status sshd.service
● sshd.service - OpenSSH Daemon
   Loaded: loaded (/usr/lib/systemd/system/sshd.service; disabled; vendor preset: disabled)
   Active: active (running) since Sun 2018-04-22 23:51:43 CST; 6s ago
 Main PID: 9429 (sshd)
    Tasks: 1 (limit: 4915)
   Memory: 1.7M
   CGroup: /system.slice/sshd.service
           └─9429 /usr/bin/sshd -D

4月 22 23:51:43 xiaoliu-manjaro systemd[1]: Started OpenSSH Daemon.
4月 22 23:51:43 xiaoliu-manjaro sshd[9429]: Server listening on 0.0.0.0 port 22.
4月 22 23:51:43 xiaoliu-manjaro sshd[9429]: Server listening on :: port 22.
$ ss -tmlp
State      Recv-Q      Send-Q            Local Address:Port            Peer Address:Port                                                                                                    
LISTEN     0           128                     0.0.0.0:ssh                  0.0.0.0:*         
	 skmem:(r0,rb87380,t0,tb16384,f0,w0,o0,bl0,d0)                                              
LISTEN     0           128                        [::]:ssh                     [::]:*         
	 skmem:(r0,rb87380,t0,tb16384,f0,w0,o0,bl0,d0)
$ ssh localhost
Last login: Sun Apr 22 17:22:36 2018 from ::1

附錄

命令

• ss -tnlp
• systemctl status sshd.service
• systemctl start sshd.service
• ssh localhost

參考

• ArchWiki中Secure Shell章節: https://wiki.archlinux.org/index.php/OpenSSH