SLACKWARE NTP CONFIGURATION (BRAZIL / BRT)

OVERVIEW

This document describes a minimal and explicit configuration for
synchronizing system time on Slackware using NTP (ntpd).

The setup is scoped specifically for systems in Brazil, using servers
from the Brazilian NTP pool. The goal is reliable and predictable time
synchronization without additional tooling or abstraction layers.


DESIGN GOALS

- use Slackware’s native ntpd service
- avoid unnecessary automation
- keep configuration auditable and simple
- prefer regional NTP servers for lower latency
- ensure hardware and system clocks are consistent


ASSUMPTIONS

- Slackware is running on the system
- ntp is installed (from the Slackware N series)
- the system timezone is already set correctly
- the user has root access


INITIAL TIME SYNCHRONIZATION

Before enabling ntpd, synchronize the system clock manually using a
Brazilian NTP server:

    ntpdate pool.ntp.br

After the system time is correct, update the hardware clock:

    hwclock --systohc --localtime

This ensures both clocks start in a consistent state.


NTP CONFIGURATION

Edit the NTP configuration file:

    vim /etc/ntp.conf

Configure ntpd to use Brazilian NTP servers:

    server a.st1.ntp.br iburst
    server b.st1.ntp.br iburst
    server c.st1.ntp.br iburst
    server d.st1.ntp.br iburst
    server gps.ntp.br iburst

The iburst option allows faster initial synchronization when ntpd
starts.


ENABLING NTPD AT BOOT

Make the rc.ntpd script executable:

    chmod +x /etc/rc.d/rc.ntpd

Start the service immediately without rebooting:

    /etc/rc.d/rc.ntpd start

At this point, ntpd will synchronize time automatically on each boot.


VERIFICATION

To verify that ntpd is running:

    ps aux | grep ntpd

To check synchronization status:

    ntpq -p

Peers marked with an asterisk (*) indicate the active time source.


NOTES ON TIMEZONE

This document assumes the system timezone is already set correctly for
Brazil (BRT). NTP synchronizes time in UTC internally; the local timezone
is handled separately by the system.


CONCLUSION

Accurate time synchronization is essential for logging, package
verification, and time-sensitive services.

By using Slackware’s native ntpd service and regional Brazilian NTP
servers, this configuration provides a simple, reliable, and
maintainable solution without unnecessary complexity.


APPENDIX: SAMPLE /etc/ntp.conf

The following is a complete example configuration based on Slackware’s
default ntp.conf, adjusted to use Brazilian NTP servers.

-----------------------------------------------------------------------

server 127.127.1.0
fudge  127.127.1.0 stratum 10

server a.st1.ntp.br iburst
server b.st1.ntp.br iburst
server c.st1.ntp.br iburst
server d.st1.ntp.br iburst
server gps.ntp.br iburst

statsdir /var/lib/ntp/stats
driftfile /var/lib/ntp/drift
pidfile /var/run/ntpd.pid

restrict default limited kod nomodify notrap nopeer noquery
restrict -6 default limited kod nomodify notrap nopeer noquery

restrict 127.0.0.1
restrict ::1


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Last Modified: 2026-01-03 05:26:54 UTC