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.
SPAN, RSPAN, and ERSPAN configured on real Cisco gear, with the ERSPAN packets captured arriving at a real Linux host. Three ways to mirror traffic to Wireshark, separated by how far the analyzer sits from the traffic.
A static route stays in the table as long as the interface is up, even when the path is dead. This post pairs object tracking with an IP SLA probe to build a static route that tests the path, then kills the path to prove it works.
IP SLA answers "is this path usable," which is not the same question as "is this link up." Captured on CML with IOS XE 17.18.2: ICMP and jitter probes against a deliberately degraded link, then a full tracked failover with the SLA timing out, %TRACK-6-STATE logging the object down, and the...
NetFlow v5, v9, Flexible NetFlow, and IPFIX do the same job differently. This comparison shows which fields, templates, and transport each supports so you pick the one your collector and your data actually need.
Flexible NetFlow tells you who is making the link busy, talking to what, on which port. Build the record, monitor, and exporter on Cisco IOS XE, export flows to a real Linux collector, and decode them so you see the data arrive.
TFTP and FTP behave very differently when you copy configs and images off a router. This article backs up a real IOS XE config over both to a Linux server, with genuine transfer output and an honest speed comparison.
DHCP discovery is broadcast and routers do not forward broadcasts, yet central DHCP servers work fine. This article builds server, relay, and client on three IOS XE routers and shows how ip helper-address makes relay work, reading state on all three.
Configure Cisco IOS XE logging to a real Linux syslog server: severity levels, logging host, synced clocks, and how to read the actual messages that arrive at the collector.
SNMP architecture explained, then put to work: polling a real Cisco IOS XE router from Linux with both SNMPv2c and SNMPv3, including what wrong credentials look like. Covers managers, agents, OIDs, and MIBs.
Wrong device time breaks certificate validation, log correlation, and time-based auth. This article deploys NTP on real Cisco IOS XE: one router as ntp master, the others syncing to it, with genuine show output at every stage.
Static NAT, dynamic NAT, and PAT configured on a real IOS XE router in CML, with the translation table read after each one. R1 is the NAT boundary and you see exactly how each flavor rewrites addresses.