How To Set Static IP and Manage Services in RHEL

[root@linuxhelp ~]# lsof -i
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
avahi-dae 774 avahi 12u IPv4 18732 0t0 UDP *:mdns
avahi-dae 774 avahi 13u IPv4 18733 0t0 UDP *:49742
chronyd 817 chrony 1u IPv4 17905 0t0 UDP *:ntp
chronyd 817 chrony 2u IPv6 17906 0t0 UDP *:ntp
chronyd 817 chrony 3u IPv4 17907 0t0 UDP localhost:323
chronyd 817 chrony 5u IPv6 17908 0t0 UDP localhost:323
sshd 1637 root 3u IPv4 21843 0t0 TCP *:ssh (LISTEN)
sshd 1637 root 4u IPv6 21845 0t0 TCP *:ssh (LISTEN)
.
.
.
master 2249 root 14u IPv6 22540 0t0 TCP localhost:smtp (LISTEN)
cupsd 3025 root 10u IPv6 26370 0t0 TCP localhost:ipp (LISTEN)
cupsd 3025 root 11u IPv4 26371 0t0 TCP localhost:ipp (LISTEN)
yum 3678 root 6u IPv4 28945 0t0 UDP 192.168.5.196:59039-> google-public-dns-a.google.com:domain
urlgrabbe 4260 root 6u IPv4 31443 0t0 TCP 192.168.5.196:56556-> 14.139.62.20:http (ESTABLISHED)

To show list of sockets with their program name, use netstat command.

[root@linuxhelp ~]# netstat -tulpn
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 2249/master
tcp 0 0 0.0.0.0:38925 0.0.0.0:* LISTEN 1799/rpc.statd
tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 1639/rpcbind
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1637/sshd
tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 3025/cupsd
.
.
.
udp 0 0 0.0.0.0:47457 0.0.0.0:* 1799/rpc.statd
udp6 0 0 :::111 :::* 1639/rpcbind
udp6 0 0 :::123 :::* 817/chronyd
udp6 0 0 :::784 :::* 1639/rpcbind
udp6 0 0 ::1:323 :::* 817/chronyd
udp6 0 0 :::46476 :::* 1799/rpc.statd

To disable service

To check the status of the service use systemctl command.

[root@linuxhelp ~]# systemctl status sshd
sshd.service - OpenSSH server daemon
Loaded: loaded (/usr/lib/systemd/system/sshd.service  enabled)
Active: active (running) since Fri 2016-04-15 10:48:43 IST  4h 39min ago
Main PID: 1637 (sshd)
CGroup: /system.slice/sshd.service
??1637 /usr/sbin/sshd -D
Apr 15 10:48:43 linuxhelp systemd[1]: Started OpenSSH server daemon.
Apr 15 10:48:43 linuxhelp sshd[1637]: Server listening on 0.0.0.0 port 22.
Apr 15 10:48:43 linuxhelp sshd[1637]: Server listening on :: port 22.

[root@linuxhelp ~]# systemctl stop sshd
[root@linuxhelp ~]# systemctl disable sshd
rm ' /etc/systemd/system/multi-user.target.wants/sshd.service' 

[root@linuxhelp ~]# systemctl status sshd
sshd.service - OpenSSH server daemon
Loaded: loaded (/usr/lib/systemd/system/sshd.service  enabled)
Active: active (dead)

If you need to get a list of all started services run service &ndash status-all command.

[root@linuxhelp ~]# service --status-all
iprdump.service - LSB: Start the ipr dump daemon
Loaded: loaded (/etc/rc.d/init.d/iprdump)
Active: active (running) since Fri 2016-04-15 10:48:31 IST  4h 48min ago
Main PID: 853 (iprdump)
CGroup: /system.slice/iprdump.service
??853 /sbin/iprdump --daemon

Apr 15 10:48:31 linuxhelp iprdump[847]: Starting iprdump: [ OK ]
Apr 15 10:48:31 linuxhelp systemd[1]: Started LSB: Start the ipr dump daemon.
iprinit.service - LSB: Start the ipr init daemon
Loaded: loaded (/etc/rc.d/init.d/iprinit)
Active: active (running) since Fri 2016-04-15 10:48:31 IST  4h 48min ago
Main PID: 844 (iprinit)
CGroup: /system.slice/iprinit.service
??844 /sbin/iprinit --daemon

Apr 15 10:48:30 linuxhelp systemd[1]: Starting LSB: Start the ipr init daemon...
Apr 15 10:48:31 linuxhelp iprinit[802]: Starting iprinit: [ OK ]
Apr 15 10:48:31 linuxhelp systemd[1]: Started LSB: Start the ipr init daemon.
Hint: Some lines were ellipsized, use -l to show in full.
iprupdate.service - LSB: Start the iprupdate utility
Loaded: loaded (/etc/rc.d/init.d/iprupdate)
Active: active (running) since Fri 2016-04-15 10:48:31 IST  4h 48min ago
Main PID: 839 (iprupdate)
CGroup: /system.slice/iprupdate.service
??839 /sbin/iprupdate --daemon

Apr 15 10:48:30 linuxhelp systemd[1]: Starting LSB: Start the iprupdate uti.....
Apr 15 10:48:31 linuxhelp iprupdate[766]: Starting iprupdate: [ OK ]
Apr 15 10:48:31 linuxhelp systemd[1]: Started LSB: Start the iprupdate utility.
Hint: Some lines were ellipsized, use -l to show in full.
netconsole module not loaded
Configured devices:
lo Auto_Ethernet eno16777736
Currently active devices:
lo eno16777736

To list all the enabled and disabled services use list-unit-files option.

[root@linuxhelp ~]# systemctl list-unit-files
UNIT FILE STATE
proc-sys-fs-binfmt_misc.automount static
dev-hugepages.mount static
dev-mqueue.mount static
proc-fs-nfsd.mount static
proc-sys-fs-binfmt_misc.mount static
tmp.mount disabled
var-lib-nfs-rpc_pipefs.mount static
brandbot.path disabled
cups.path enabled
systemd-ask-password-console.path static
session-2.scope static
abrt-ccpp.service enabled
abrt-oops.service enabled
abrt-pstoreoops.service disabled
abrt-vmcore.service enabled
abrt-xorg.service enabled
abrtd.service enabled

To manage services, execute “ systemctl” command with -H option.

[root@linuxhelp ~]# systemctl -H linuxhelp.com status sshd

This command will check the status of sshd service in remote host “ linuxhelp.com”

.