为什么“ service sshd start”命令无法返回命令提示符？

Question

I'm install a new CentOS7, its sshd service works fine. Then I download the source code of openssh7.5p1, build it and install it to the default directory "/usr/local/sbin/sshd". I want to use it to replace the system's sshd.

1. I modify the file "/usr/lib/systemd/system/sshd.service", change following line: old: ExecStart=/usr/sbin/sshd $OPTIONS new: ExecStart=/usr/local/sbin/sshd $OPTIONS

2. After that, type command "service sshd start", the command can not return and seems hang up. Looks as follows: [root@localhost ~]# service sshd start Redirecting to /bin/systemctl start sshd.service

3. I press Ctl+C to terminate the command. Then use command "netstat -ntlp" to find that the "sshd" already started, not sure why the "service sshd start" can not return to prompt. [root@localhost ~]# netstat -ntlp Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 1/systemd
tcp 0 0 192.168.122.1:53 0.0.0.0:* LISTEN 2443/dnsmasq
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 63144/sshd
tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 1043/cupsd
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 1815/master
tcp6 0 0 :::111 :::* LISTEN 1/systemd
tcp6 0 0 :::22 :::* LISTEN 63144/sshd
tcp6 0 0 ::1:631 :::* LISTEN 1043/cupsd
tcp6 0 0 ::1:25 :::* LISTEN 1815/master

4. I try to start sshd manually, it works fine, the sshd started successfully(no any warning message) and the command return immediately. The command as follows: [root@localhost ~]# /usr/local/sbin/sshd -f /etc/ssh/sshd_config

Any help is appreciated. Let me know if you want to known more information. Thanks.

Answer 1

How about tinkering With type in your .service ? have you tried to set it to idle ? maybe systemd waits to receive a message from sshd and seems to hang..