The services running alongside routing that keep a network usable. Articles tagged IP Services cover NAT, DHCP, NTP, SNMP, syslog, NetFlow and IP SLA on Cisco IOS XE.
The NAT config looks correct and nothing is translating. One command splits the problem in two: no entry means the traffic never matched, an entry means the failure is downstream. Captured on IOS XE 17.18.2 in CML, where a single missing ip nat inside leaves the table empty at 0 hits.
Harden a Cisco router by disabling unused services, proven with a real before-and-after Nmap scan taking Telnet from open to closed, plus syslog design.
Configure authenticated NTP on Cisco IOS XE, why IOS flags MD5 as weak, and how ntp authenticate and trusted-key stop a rogue server moving your clock.
NAT, DHCP, and IP SLA faults rarely leave clues in show ip route. Five services ticket scenarios with the exact translation table, binding, or tracking object to check for each, grounded in real lab behavior.
DHCPv6 prefix delegation, general prefixes, and NPTv6: the IPv6 services engineers often skip, shown with real CML output of a delegated prefix flowing all the way to a downstream interface.
Embedded Packet Capture puts Wireshark-grade capture inside the IOS XE router itself: no SPAN, no capture laptop, no cabling. Includes a real on-router capture from a CML lab and the syntax difference that will bite you.
Build SNMPv3 in production form: users, groups, views, and the three security levels. The payoff is a real encrypted trap arriving and being decrypted on a Linux receiver, with no cleartext community strings on the wire.
The IOS DHCP server does far more than network, default-router, dns-server. This article covers options for PXE boot and phones, DHCP classes, and manual bindings, with real lease output from a CML lab.
Two customers with identical 10.5.5.0/24 subnets reach one shared exit through a single router. VRF-aware NAT on IOS XE keeps them separate, and this CML lab build shows two translation tables holding identical inside-local addresses.
Conditional debug lets you ask a Cisco IOS XE router a narrow question instead of melting it with unfiltered output. Proven in the lab: two pings run, and only the matching one appears in the debug.
NTP keeps most networks within a second; trading floors, 5G fronthaul, and substations need microseconds. This article explains the structural limit that makes NTP incapable of that job and how PTP (IEEE 1588) solves it.
SLAAC, stateless DHCPv6, and stateful DHCPv6 can all run at once, arbitrated by the M and O flags. This article untangles all three, then builds a stateful server with a relay on Cisco IOS XE and a real Linux client taking a lease.