一、网络是否通畅
方法：
- ping ip或域名
- telnet ip或域名
[root@Docker_Ser ~]# ping 192.168.10.237
PING 192.168.10.237 (192.168.10.237) 56(84) bytes of data.
64 bytes from 192.168.10.237: icmp_seq=1 ttl=64 time=0.057 ms
64 bytes from 192.168.10.237: icmp_seq=2 ttl=64 time=0.038 ms
^C
--- 192.168.10.237 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1039ms
rtt min/avg/max/mdev = 0.038/0.047/0.057/0.011 ms
[root@Docker_Ser ~]# telnet 192.168.10.237 22
Trying 192.168.10.237...
Connected to 192.168.10.237.
Escape character is '^]'.
SSH-2.0-OpenSSH_6.6.1
^[
Protocol mismatch.
Connection closed by foreign host.
[root@Docker_Ser ~]#二、防火墙限制
方法：
- 本地ping 或 telnet 是正常的，但其他机器无法 ping 或 telent 通
- 检查 firewall（ubuntu是ufw） 是否关闭
- 检查 selinux 是否关闭
[root@Docker_Ser ~]# systemctl status firewalld.service
● firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
Active: inactive (dead)
Docs: man:firewalld(1)
[root@Docker_Ser ~]# cat /etc/selinux/config
# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
# enforcing - SELinux security policy is enforced.
# permissive - SELinux prints warnings instead of enforcing.
# disabled - No SELinux policy is loaded.
SELINUX=disabled
# SELINUXTYPE= can take one of three two values:
# targeted - Targeted processes are protected,
# minimum - Modification of targeted policy. Only selected processes are protected.
# mls - Multi Level Security protection.
SELINUXTYPE=targeted
[root@Docker_Ser ~]# 三、检查本地服务是否启动
方法：
- 端口是否监听：netstat -nltup | grep "22"
- 进程是否启动：ps -ef | grep "ssh"
[root@Docker_Ser ~]# netstat -nltup | grep "22"
tcp 0 0 192.168.10.237:22 0.0.0.0:* LISTEN 1072/sshd
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 2122/master
tcp6 0 0 ::1:25 :::* LISTEN 2122/master
[root@Docker_Ser ~]# ps -ef | grep "ssh"
root 1072 1 0 2024 ? 00:00:00 /usr/sbin/sshd -D
root 12821 1072 0 21:08 ? 00:00:00 sshd: root@pts/0
root 13084 12823 0 21:12 pts/0 00:00:00 grep --color=auto ssh
[root@Docker_Ser ~]# 四、检查时间是否正确
方法：
- 检查时区和时间
[root@Docker_Ser ~]# timedatectl
Local time: Wed 2025-02-05 21:16:09 CST
Universal time: Wed 2025-02-05 13:16:09 UTC
RTC time: Wed 2025-02-05 13:16:02
Time zone: Asia/Shanghai (CST, +0800)
NTP enabled: no
NTP synchronized: no
RTC in local TZ: no
DST active: n/a
[root@Docker_Ser ~]# date
Wed Feb 5 21:16:28 CST 2025
[root@Docker_Ser ~]#
