Antonio Perez

NTP Configuration on Aruba CX 6300 / 6400 (Houston, TX) To configure the Windows Time Service (w32time) and synchronize with specific NTP servers, run the following commands as Administrator from PowerShell or CMD.

w32tm /config /manualpeerlist:"0.pool.ntp.org 1.pool.ntp.org 2.pool.ntp.org 3.pool.ntp.org" /syncfromflags:manual /reliable:yes /update
net stop w32time
net start w32time
w32tm /resync

*Use this option for general-purpose global synchronization.*

w32tm /config /manualpeerlist:"time.google.com time.cloudflare.com" /syncfromflags:manual /reliable:yes /update
net stop w32time
net start w32time
w32tm /resync

*Use this option if you prefer high-availability public NTP providers.*

After applying the configuration, check synchronization status:

w32tm /query /status
w32tm /query /peers

Expected results:

• Source → should show one of the configured NTP servers.
• Stratum → indicates synchronization level (lower = better).
• Last Successful Sync Time → confirms proper operation.

• /manualpeerlist → Defines NTP servers (internal or external).
• /syncfromflags:manual → Forces use of the listed servers only.
• /reliable:yes → Marks this server as a reliable time source (for domain controllers).
• /update → Applies settings immediately.
• /resync → Forces an instant synchronization.

To configure the switch to synchronize its time using public NTP servers and apply the correct time zone for Houston (Central Time), run the following commands in configuration mode:

configure terminal
 
! Configure DNS servers for name resolution (required for NTP hostnames)
ip dns server-address 8.8.8.8
ip dns server-address 1.1.1.1
 
! Configure public NTP servers (requires DNS resolution)
ntp server 0.pool.ntp.org
ntp server 1.pool.ntp.org
ntp server 2.pool.ntp.org
ntp server 3.pool.ntp.org
 
! Enable NTP service
ntp enable
 
! Set time zone to Central Time (Houston, TX)
clock timezone america/chicago
 
exit
write memory

Check synchronization and clock status:

show ntp associations
show ntp status
show clock

Expected output:

• show ntp associations → an asterisk (*) indicates the currently synchronized NTP source.
• show clock → displays local time adjusted to Central Time (CST/CDT).
• show ntp status → should report synchronized after a few minutes.

• DNS servers (dns server) are mandatory if you use hostnames (e.g. pool.ntp.org); otherwise, specify NTP servers by IP.
• america/chicago automatically handles daylight saving time.
• If using an internal NTP source (e.g. Windows Server), replace pool servers with its IP (e.g. ntp server 10.28.64.22).
• NTP uses UDP port 123 — ensure it is allowed for outbound traffic.
• Save configuration permanently with write memory.

This configuration allows the Aruba 2930M switch (AOS-Switch) to keep accurate time using public NTP IP servers and the correct Central Time zone.

configure terminal
 
# Configure DNS servers (only if not already defined)
no ip dns server-address priority 1
no ip dns server-address priority 2
ip dns server-address priority 1 8.8.8.8
ip dns server-address priority 2 1.1.1.1
 
# Configure public NTP servers (IP addresses only)
ntp server 216.239.35.0       
ntp server 162.159.200.1       
ntp server 129.6.15.28         
ntp server 132.163.96.5      
 
# Set time zone to Central Time (Houston, TX)
time timezone -360
 
# Enable Daylight Saving Time for USA
time daylight-time-rule continental-us-and-canada
 
exit
write memory

Run the following commands to verify time synchronization:

show ntp status
show time
show clock

Expected output:

• System time synchronized to NTP Server → indicates active NTP source.
• Time zone offset: -360 → confirms Central Time (UTC−6).
• Daylight time rule: USA → daylight saving enabled.

• The 2930M does not support NTP hostnames — only IP addresses.
• If you have a local NTP server (e.g., Windows at 10.28.64.22), replace the public IPs with:

    ntp server 10.28.64.22
    

• Use show ip dns to confirm DNS configuration.
• Save configuration permanently with write memory.

This configuration enables NTP synchronization, DNS resolution, and applies the correct Central Time zone (Houston, TX) with daylight saving rules for the continental U.S. and Canada.

configure terminal
 
! Enable NTP mode
timesync ntp
ntp enable
 
! Configure DNS servers for hostname resolution
ip dns server-address priority 1 8.8.8.8
ip dns server-address priority 2 1.1.1.1
 
! Configure NTP servers (can use hostnames if DNS is working)
ntp server 0.pool.ntp.org
ntp server 1.pool.ntp.org
ntp server 2.pool.ntp.org
ntp server 3.pool.ntp.org
 
! Set time zone to Central Time (UTC−6)
time timezone -360
 
! Enable daylight saving time for continental U.S. and Canada
time daylight-time-rule continental-us-and-canada
 
exit
write memory

Verify NTP synchronization, DNS status, and system time:

show ntp status
show ntp associations
show ip dns
show time
show clock

Expected results:

• System time synchronized to NTP Server … → indicates active synchronization.
• Time zone offset: -360 → confirms Central Time.
• Daylight time rule: continental-us-and-canada → DST adjustment active.
• DNS server(s): 8.8.8.8, 1.1.1.1 → confirms DNS configuration.

• Aruba 3810M supports FQDN or IP for NTP servers — DNS must be reachable.
• To use an internal NTP source (e.g. Windows Server), replace pool servers with:

    ntp server 10.28.64.22
    

• If DNS is unreachable, use IP addresses directly for NTP.
• NTP uses UDP port 123; confirm outbound reachability.
• Save configuration permanently with write memory.

Validated configuration for accurate timekeeping with SNTP (unicast), DNS resolvers, Central Time (UTC−6) and U.S. DST.

! Already applied (from running-config):
sntp unicast client enable
sntp server 216.239.35.0
sntp server 162.159.200.1
sntp server 129.6.15.28
sntp server 132.163.96.5
clock summer-time recurring USA
clock timezone -6 minutes 0
ip name-server "8.8.8.8"
ip name-server "1.1.1.1"
 
exit
write memory

show sntp
show clock
show running-config | include sntp|clock|name-server

Expected:

• SNTP Client Mode: Unicast and servers Reachable
• Clock timezone offset: -6 and DST: USA (active when applicable)
• Last sync time updates periodically (UDP/123 reachable)

• DNOS 6 in N3000 uses SNTP (no full NTP).
• If DNS is down, keep servers by IP (as configured).
• Ensure outbound UDP/123 is allowed from the chosen source-interface.
• Persist with write memory after any change.

Use IANA timezone names. For Houston, use America/Chicago (DST automático).

configure terminal
 
! DNS (opcional, para resolver FQDN)
ip name-server 8.8.8.8
ip name-server 1.1.1.1
 
! NTP servers (FQDN soportado si hay DNS)
ntp server 0.pool.ntp.org
ntp server 1.pool.ntp.org
ntp server 2.pool.ntp.org
ntp server 3.pool.ntp.org
 
! Zona horaria IANA (Houston)
clock timezone America/Chicago
 
end
write memory

show ntp servers
show ntp status
show clock

Esperado:

• Uno de los NTP marcado como peer activo.
• show clock mostrando hora local con CDT/CST según corresponda (DST automático).

This configuration enables DNS resolution, adds public NTP servers, and applies the Central Time zone.

configure terminal
 
ip name-server 8.8.8.8
ip name-server 1.1.1.1
 
ntp server 0.pool.ntp.org
ntp server 1.pool.ntp.org
ntp server 2.pool.ntp.org
ntp server 3.pool.ntp.org
 
clock timezone US/Central
 
end
write memory

show ntp status
show ntp associations
show clock

Expected:

• One server selected as the system peer.
• show clock shows local time with timezone US/Central.

• ip name-server configures DNS resolvers on EOS. :contentReference[oaicite:0]{index=0}
• ntp server <ip|fqdn> adds time sources; EOS NTP is enabled by default. Use iburst if desired for faster initial sync. :contentReference[oaicite:1]{index=1}
• Time zone labels accept IANA/alias names like US/Central or America/Chicago (clock timezone ? lists options). :contentReference[oaicite:2]{index=2}
• To force the source address, use ntp local-interface <intf> (e.g., Management1 or a VLAN SVI). :contentReference[oaicite:3]{index=3}
• If NTP must traverse VRF MGMT, append vrf MGMT to each server line. :contentReference[oaicite:4]{index=4}

This configuration enables DNS resolution, adds public NTP servers, and applies Central Time (Houston) with U.S. daylight saving.

conf t
ip name-server 8.8.8.8
ip name-server 1.1.1.1
 
ntp server 0.pool.ntp.org
ntp server 1.pool.ntp.org
ntp server 2.pool.ntp.org
ntp server 3.pool.ntp.org
 
clock timezone CST -6
clock summer-time CDT recurring 2 Sun Mar 2:00 1 Sun Nov 2:00
 
end
write memory

If NTP must go out the management path, bind it to Mgmt-vrf and pick a stable source interface (e.g., Loopback0 or a SVI).

conf t
! choose a stable source address for NTP packets
ntp source Loopback0
 
! send NTP via the management VRF
ntp server vrf Mgmt-vrf 0.pool.ntp.org
ntp server vrf Mgmt-vrf 1.pool.ntp.org
ntp server vrf Mgmt-vrf 2.pool.ntp.org
ntp server vrf Mgmt-vrf 3.pool.ntp.org
end
write memory

show ntp associations
show ntp status
show clock detail
show run | i ntp|name-server|clock

Expected:

• One server marked as the system peer in show ntp associations.
• show clock detail shows local time with CST/CDT and DST state.
• DNS servers listed under name-server.

• Cisco IOS XE acepta FQDN o IP en ntp server.
• Si usas servidores internos, reemplaza los del pool por tu host (ej.:

conf t
no ntp server 0.pool.ntp.org
no ntp server 1.pool.ntp.org
no ntp server 2.pool.ntp.org
no ntp server 3.pool.ntp.org
ntp server 10.28.64.22 prefer
end
write memory

)

• Asegura salida UDP/123 desde la interfaz origen/VRF usados.
• clock summer-time … recurring aplica el cambio a DST automáticamente (1 h).