Day: August 28, 2023

by

Disabling Avahi-Daemon on CentOS 7

I was having a bit of difficult of turning Avahi-Daemon which is also called mDNS since I do not need the Service. When I use the command

# systemctl status avahi-daemon
● avahi-daemon.service - Avahi mDNS/DNS-SD Stack
   Loaded: loaded (/usr/lib/systemd/system/avahi-daemon.service; enabled; vendor preset: enabled)
   Active: active (running) since Mon 2023-08-28 08:46:26 +08; 14h ago
 Main PID: 36457 (avahi-daemon)
   Status: "avahi-daemon 0.6.31 starting up."
    Tasks: 2
   Memory: 676.0K
   CGroup: /system.slice/avahi-daemon.service
           ├─36457 avahi-daemon: running [hpc-r001.local]
           └─36494 avahi-daemon: chroot helper
.....
.....
.....

Unable to Stop ???

I tried to stop it, but the daemon did not stop….. Hmmmmm

# systemctl stop avahi-daemon
Warning: Stopping avahi-daemon.service, but it can still be activated by:
  avahi-daemon.socket
[root@hpc-r001 ~]# systemctl status avahi-daemon
● avahi-daemon.service - Avahi mDNS/DNS-SD Stack
   Loaded: loaded (/usr/lib/systemd/system/avahi-daemon.service; enabled; vendor preset: enabled)
   Active: active (running) since Mon 2023-08-28 23:11:54 +08; 10s ago
 Main PID: 372559 (avahi-daemon)
   Status: "avahi-daemon 0.6.31 starting up."
    Tasks: 2
   Memory: 704.0K
   CGroup: /system.slice/avahi-daemon.service
           ├─372559 avahi-daemon: running [hpc-r001.local]
           └─372563 avahi-daemon: chroot helper

Unable to Disable ???

I tried to disable as well. But…… still alive?

# systemctl disable avahi-daemon
Removed symlink /etc/systemd/system/multi-user.target.wants/avahi-daemon.service.
Removed symlink /etc/systemd/system/dbus-org.freedesktop.Avahi.service.
Removed symlink /etc/systemd/system/sockets.target.wants/avahi-daemon.socket.
[root@hpc-r001 ~]# systemctl status avahi-daemon
● avahi-daemon.service - Avahi mDNS/DNS-SD Stack
   Loaded: loaded (/usr/lib/systemd/system/avahi-daemon.service; disabled; vendor preset: enabled)
   Active: active (running) since Mon 2023-08-28 23:12:25 +08; 2min 32s ago
 Main PID: 372707 (avahi-daemon)
   Status: "avahi-daemon 0.6.31 starting up."
   CGroup: /system.slice/avahi-daemon.service
           ├─372707 avahi-daemon: running [hpc-r001.local]
           └─372709 avahi-daemon: chroot helper

Finally…… Mask, Disable then stop.

To prevent a service from running you need to “mask” it first

# systemctl mask avahi-daemon
Created symlink from /etc/systemd/system/avahi-daemon.service to /dev/null.
# systemctl disable avahi-daemon
# systemctl stop avahi-daemon


# systemctl status avahi-daemon
● avahi-daemon.service
   Loaded: masked (/dev/null; bad)
   Active: inactive (dead) since Mon 2023-08-28 23:15:42 +08; 20min ago
 Main PID: 372707 (code=exited, status=0/SUCCESS)
by

Using NMCLI to manage Network on Rocky Linux 8

Point 1: View all the saved connections

# nmcli connection show
ens1f0     XXXX-XXXX-XXXX-XXXX-XXXX  ethernet  ens1f0
ens1f1     YYYY-YYYY-YYYY-YYYY-YYYY  ethernet  ens1f1
ens10f0    ZZZZ-ZZZZ-ZZZZ-ZZZZ-ZZZZ  ethernet  --
ens10f1    AAAA-AAAA-AAAA-AAAA-AAAA  ethernet  --

Point 2a: Stop Network

You can use the command “nmcli connection down ssid/uuid". For example 

# nmcli connection down XXXX-XXXX-XXXX-XXXX-XXXX
Connection 'eno0' successfully deactivated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/3)

Point 2b: Start Network

You can use the command “nmcli connection up ssid/uuid". For example 

# nmcli connection up XXXX-XXXX-XXXX-XXXX-XXXX
Connection 'eno0' successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/3)

Point 3: Device Connection

To check the Device status

# nmcli dev status
ens1f0  ethernet  connected     ens1f0
eno1f1  ethernet  connected     ens1f1
eno10f0  ethernet  disconnected  --
eno10f1  ethernet  disconnected  --

Point 4: List all Device 

# nmcli device show
GENERAL.DEVICE:                         ens1f0
GENERAL.TYPE:                           ethernet
GENERAL.HWADDR:                         XX:XX:XX:XX:XX:XX
GENERAL.MTU:                            1500
GENERAL.STATE:                          100 (connected)
GENERAL.CONNECTION:                     ens1f0
GENERAL.CON-PATH:                       /org/freedesktop/NetworkManager/ActiveConnection/2
WIRED-PROPERTIES.CARRIER:               on
IP4.ADDRESS[1]:                         192.168.0.1
IP4.GATEWAY:                            192.168.0.254
IP4.ROUTE[1]:                           dst = 0.0.0.0/0, nh = 192.168.0.254, mt = 101
IP4.ROUTE[2]:                           dst = 198.168.0.0/19, nh = 0.0.0.0, mt = 101
IP6.ADDRESS[1]:                         xxxx::xxxx:xxxx:xxxx:xxxx/64
IP6.GATEWAY:                            --
IP6.ROUTE[1]:                           dst = fe80::/64, nh = ::, mt = 1024

GENERAL.DEVICE:                         eno1f1
GENERAL.TYPE:                           ethernet
GENERAL.HWADDR:                         94:6D:AE:9B:76:1C
GENERAL.MTU:                            1500
GENERAL.STATE:                          100 (connected)
GENERAL.CONNECTION:                     eno1f1
GENERAL.CON-PATH:                       /org/freedesktop/NetworkManager/ActiveConnection/4
WIRED-PROPERTIES.CARRIER:               on
IP4.ADDRESS[1]:                         192.168.200.201/19
IP4.GATEWAY:                            --
IP4.ROUTE[1]:                           dst = 192.168.192.0/19, nh = 0.0.0.0, mt = 102
IP6.ADDRESS[1]:                         fe80::966d:aeff:fe9b:761c/64
IP6.GATEWAY:                            --
IP6.ROUTE[1]:                           dst = fe80::/64, nh = ::, mt = 1024

Point 5: Start and Stop Device 

# nmcli con down ens1d1
# nmcli con up ens1d1

References:

  1. nmcli command in Linux with Examples