# 11.1 Adjust System Time

For many services and proccesses a security check is the diffrence in time settings, this is why Red Hat Linux has an advanced system for time management.


### Checking time settings
Check the time settings with the ```timedatectl``` command:

```bash
[root@rhcsa ~]# timedatectl
               Local time: Wed 2020-07-29 05:56:51 EDT
           Universal time: Wed 2020-07-29 09:56:51 UTC
                 RTC time: Wed 2020-07-29 09:56:51
                Time zone: America/New_York (EDT, -0400)
System clock synchronized: no
              NTP service: inactive
          RTC in local TZ: no
```

The more important settings here other then knowing the time of the VM.
```
                Time zone: America/New_York (EDT, -0400)
System clock synchronized: no
              NTP service: inactive
```
These settings tell you the time zone the vm is in, if the clock is syncronized and wether **N**etwork **T**ime **P**rotocol or NTP is turned on.

### Turning on NTP
First we must make sure that chrony, this is the ntp protocol server is installed.
```bash
dnf install chrony
```

Now we must check wether the service is on:
```bash
systemctl status chronyd
```

If the status of chronyd is ```dead/inactive``` use the following command to turn it on and enable it:
```bash
systemctl enable --now chronyd
```

To turn on the NTP in the timedatectl command:
```bash
timedatectl set-ntp true
```

Result can be checked with ```timedatectl```
```bash
[root@rhcsa ~]# timedatectl
               Local time: Wed 2020-07-29 06:00:39 EDT
           Universal time: Wed 2020-07-29 10:00:39 UTC
                 RTC time: Wed 2020-07-29 10:00:40
                Time zone: America/New_York (EDT, -0400)
System clock synchronized: no
              NTP service: active
          RTC in local TZ: no
```

Now it is turned on but the clock is not yet syncronized this might take some time to check that.
```bash
chronyc sources -v
```
```bash
[root@rhcsa ~]# chronyc sources -v
210 Number of sources = 4

  .-- Source mode  '^' = server, '=' = peer, '#' = local clock.
 / .- Source state '*' = current synced, '+' = combined , '-' = not combined,
| /   '?' = unreachable, 'x' = time may be in error, '~' = time too variable.
||                                                 .- xxxx [ yyyy ] +/- zzzz
||      Reachability register (octal) -.           |  xxxx = adjusted offset,
||      Log2(Polling interval) --.      |          |  yyyy = measured offset,
||                                \     |          |  zzzz = estimated error.
||                                 |    |           \
MS Name/IP address         Stratum Poll Reach LastRx Last sample               
===============================================================================
^- ntp18.kashra-server.com       2   6    73    34  +5209us[+5209us] +/-   24ms
^* time.cloudflare.com           3   6    37    37  -6253ns[ -416us] +/- 3347us
^- mail.picquenot.com            2   6    37    37  -3751us[-4160us] +/-   32ms
^- reinhardt.pointpro.nl         2   6    37    36   -276us[ -276us] +/-   34ms
```

Now we need to make sure our VM is talking to our local NTP server:
```bash
[root@rhcsa ~]# vim /etc/chrony.conf
```

Remove the lines with server ```pool X.centos.pool.org``` and add:
```
server 192.168.56.100 iburst
```

The top of the file looks like this:
```bash
# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
server 192.168.56.100 iburst
#pool 2.centos.pool.ntp.org iburst
```

Restart the chronyd service:
```bash
systemctl restart chronyd
```

Check if your ntp is syncing with our server:
```bash
chronyc sources -v
```
```bash
[root@rhcsa ~]# chronyc sources -v
210 Number of sources = 1

  .-- Source mode  '^' = server, '=' = peer, '#' = local clock.
 / .- Source state '*' = current synced, '+' = combined , '-' = not combined,
| /   '?' = unreachable, 'x' = time may be in error, '~' = time too variable.
||                                                 .- xxxx [ yyyy ] +/- zzzz
||      Reachability register (octal) -.           |  xxxx = adjusted offset,
||      Log2(Polling interval) --.      |          |  yyyy = measured offset,
||                                \     |          |  zzzz = estimated error.
||                                 |    |           \
MS Name/IP address         Stratum Poll Reach LastRx Last sample               
===============================================================================
^? 192.168.56.100                 0   7     0     -     +0ns[   +0ns] +/-    0ns
```

### Changing Time Zones
We now know how to check our time with the local NTP server but we also want to change the time zone, first check the curent timezone.
```bash
timedatectl
```

You’ll see: ```Time zone: America/New_York (EDT, -0400)```<br>

Lets list all the timezones to see if we can find the one we want:
```bash
timedatectl list-timezones
```

A very very long list will apear you can scroll through the list until you find ```Amsterdam``` or we can use a slightly quicker version with ```grep```.
```bash
timedatectl list-timezones |grep Amsterdam
```
Notice that the word ```Amsterdam``` is case sensitive.




Change the timezone to Europe/Amsterdam, and you can verify the results with the ```timedatectl``` command.
```bash
[root@rhcsa ~]# timedatectl set-timezone Europe/Amsterdam
```