Route redistribution end to end on Cisco IOS XE: how seed metrics work, what each protocol demands before accepting foreign routes, and what the routing table looks like at every stage. Every capture comes from a live CML lab.
Neighbors up but a route is missing? A systematic walk through the five places an EIGRP route can die on its way to the routing table, with real failure output from a CML lab.
Two routers, two broken adjacencies, one log message. Real CML captures on IOS XE 17.18.2 show the %DUAL-5-NBRCHANGE K-value mismatch that repeats every few seconds, the AS mismatch that logs absolutely nothing, and what both look like the moment they recover.
Filter EIGRP routes with distribute lists powered by prefix lists and route maps. Both flavors configured on a live CML lab, with before-and-after routing tables and the habits that keep filtering from becoming a mystery outage.
Named mode EIGRP replaced the 32-bit composite metric with a 64-bit version: delay in picoseconds, a scaling factor before the routing table, and quiet conversions at classic/named boundaries. Decoded with real CML output.
A route in Active state with a reply outstanding, captured live on IOS XE 17.18.2 in CML: the r and rs status flags that name the silent neighbor, why packet loss gives you neighbor flaps instead of SIA, and why modern IOS XE usually logs retry limit exceeded before it ever prints %DUAL-3-SIA.
Unauthenticated EIGRP forms adjacencies with anything that speaks the protocol. This post configures MD5 key chains and HMAC-SHA-256 in classic and named mode on a live CML lab, then breaks a key to show what failure looks like.
EIGRP is the only Cisco IGP that load balances across unequal-cost paths. This lab walks variance on live IOS XE: the topology table, the feasibility check, variance 2 in named mode, and the traffic share counters that prove the split.
EIGRP summarization shrinks topology tables, speeds convergence, and bounds queries. Configure it in classic and named mode on IOS XE, watch the Null0 discard route appear, and advertise a default route with summary-address 0.0.0.0/0.
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.