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--- windows:windows_time_service_ntp [2025/10/07 09:08] – [🕒 SNTP and DNS — Dell EMC N3048P (DNOS 6.5.3.6, Houston, TX)] aperez
+++ windows:windows_time_service_ntp [2025/10/07 12:08] (current) – aperez
@@ Line 291: / Line 291: @@
 ----
+===== 🕒 NTP and DNS Configuration on Aruba 7220 (AOS 8.12, Houston, TX) =====
+Use IANA timezone names. For Houston, use ''America/Chicago'' (DST automático).
+<code bash>
+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
+</code>
+==== 🔍 Verificación ====
+<code bash>
+show ntp servers
+show ntp status
+show clock
+</code>
+**Esperado:**
+  * Uno de los NTP marcado como peer activo.
+  * ''show clock'' mostrando hora local con ''CDT/CST'' según corresponda (DST automático).
+----
+----
+===== 🕒 NTP and DNS Configuration on Arista 7050QX (EOS 4.13.x, Houston, TX) =====
+This configuration enables DNS resolution, adds public NTP servers, and applies the Central Time zone.
+<code bash>
+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
+</code>
+----
+==== 🔍 Verification ====
+<code bash>
+show ntp status
+show ntp associations
+show clock
+</code>
+Expected:
+  * One server selected as the system peer.
+  * ''show clock'' shows local time with timezone ''US/Central''.
+----
+==== 🧠 Notes ====
+  * ''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}
+----
+----
+===== 🕒 NTP and DNS on Cisco Catalyst 9500 (IOS XE 17.12) — Houston, TX =====
+DNS + NTP con zona horaria Central (CST/CDT). ''ip domain-lookup'' no es requerido en esta versión.
+<code bash>
+conf t
+ip name-server 8.8.8.8
+ip name-server 1.1.1.1
+! NTP servers (FQDN soportado)
+ntp server 0.pool.ntp.org
+ntp server 1.pool.ntp.org
+ntp server 2.pool.ntp.org
+ntp server 3.pool.ntp.org
+! (Opcional) Fuente de NTP para dirección estable
+ntp source Loopback0
+! Zona horaria Houston (Central) + DST EE.UU.
+clock timezone CST -6
+clock summer-time CDT recurring 2 Sun Mar 2:00 1 Sun Nov 2:00
+end
+write memory
+</code>
+----
+==== 🔁 (Opcional) Enviar NTP por el VRF de management ====
+Si tu salida a Internet va por **Mgmt-vrf**, usa:
+<code bash>
+conf t
+ntp source Loopback0
+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
+</code>
+----
+==== 🔍 Verificación ====
+<code bash>
+show hosts                      ! valida resolución DNS
+ping 0.pool.ntp.org             ! (o ping vrf Mgmt-vrf 0.pool.ntp.org)
+show ntp associations
+show ntp status
+show clock detail
+show run | i name-server|ntp|clock
+</code>
+**Esperado:**
+  * Un servidor con ''*'' como **system peer** en ''show ntp associations''.
+  * ''show clock detail'' mostrando CST/CDT y estado de DST.
+  * DNS resolviendo (''show hosts'').
+----
+==== 🧠 Notas ====
+  * Si algún FQDN no resuelve, prueba primero con **IP** para descartar DNS.
+  * Asegura salida **UDP/123** desde la interfaz/VRF usada por NTP.
+  * Puedes marcar un servidor como preferido:
+    <code>ntp server 0.pool.ntp.org prefer</code>
+----
+----