因为安全原因，安装完FreeBSD后默认是不允许root用户通过SSH协议进行远程登录的，但是我们可以手动配置开启它。
1、修改inetd.conf文件
打开文件/etc/inetd.conf并找到ssh两行，然后把注释去掉保存，如下：
# $FreeBSD$
#
# Internet server configuration database
#
# Define *both* IPv4 and IPv6 entries for dual-stack support.
# To disable a service, comment it out by prefixing the line with '#'.
# To enable a service, remove the '#' at the beginning of the line.
#
#ftp stream tcp nowait root /usr/libexec/ftpd ftpd -l
#ftp stream tcp6 nowait root /usr/libexec/ftpd ftpd -l
ssh stream tcp nowait root /usr/sbin/sshd sshd -i -4
ssh stream tcp6 nowait root /usr/sbin/sshd sshd -i -6
#telnet stream tcp nowait root /usr/libexec/telnetd telnetd
#telnet stream tcp6 nowait root /usr/libexec/telnetd telnetd
#shell stream tcp nowait root /usr/local/sbin/rshd rshd
#shell stream tcp6 nowait root /usr/local/sbin/rshd rshd
#login stream tcp nowait root /usr/local/sbin/rlogind rlogind
#login stream tcp6 nowait root /usr/local/sbin/rlogind rlogind
#finger stream tcp nowait/3/10 nobody /usr/libexec/fingerd fingerd -k -s
#finger stream tcp6 nowait/3/10 nobody /usr/libexec/fingerd fingerd -k -s
#
# run comsat as root to be able to print partial mailbox contents w/ biff,
# or use the safer tty:tty to just print that new mail has been received.
#comsat dgram udp wait tty:tty /usr/libexec/comsat comsat
...略
2、修改sshd_config文件
注意：这里是sshd_config而不是ssh_config文件。
打开文件/etc/ssh/sshd_config并找到PermitRootLogin这一行，然后把注释去掉保存，如下：
.....
# Authentication:
#LoginGraceTime 2m
PermitRootLogin yes
#StrictModes yes
#MaxAuthTries 6
#MaxSessions 10
#PubkeyAuthentication yes
.....
3、重启sshd服务
方式1：
service sshd restart
方式2：
/etc/rc.d/sshd restart