Agent skill · data analytics · affaan-m
network-interface-health
Diagnose interface errors, drops, CRCs, duplex mismatches, flapping, speed negotiation issues, and counter trends on routers, switches, and Linux hosts. Use when an interface shows errors, drops, CRCs, flapping, or a duplex or speed mismatch.
Why this skill is useful
Provides specific commands and diagnostic procedures for analyzing network interface health that the AI wouldn't reliably generate on its own.
What it needs
About 3k tokens when loaded. Last updated 2026-08-06. 238,342 stars on the source repository.
What this skill does
Network Interface Health Use this skill when a network symptom might be caused by a physical link, switch port, cable, transceiver, duplex setting, or congested interface. When to Use A host or VLAN has packet loss, latency spikes, or intermittent reachability. A switch or router interface shows CRCs, runts, giants, drops, resets, or flaps. You need to compare both ends of a link before replacing hardware. A change window needs before/after interface counter evidence. Monitoring reports rising ifInErrors, ifOutErrors, or ifOutDiscards. How It Works Interface counters are evidence, but the trend matters more than the absolute number. Capture a baseline, wait a measurement interval, capture again, then compare increments. On Linux hosts: Counter Reference Counter Meaning Common cause --- --- --- CRC Received frame checksum failed Bad cable, dirty fiber, bad optic, duplex mismatch input errors Aggregate receive-side errors Check sub-counters before concluding runts Frames below minimum Ethernet size Duplex mismatch, collision domain, faulty NIC giants Frames larger than expected MTU MTU mismatch or jumbo-frame boundary input drops Device could not accept inbound packets Burst, oversubscription, CPU path, queue pressure output drops Egress queue discarded packets Congestion, QoS policy, undersized uplink resets Interface hardware reset Flapping, keepalive, driver, optic, power collisions Ethernet collision counter Half duplex or negotiation mismatch Diagnosis Flow CRCs Or Input Errors 1. Confirm counters are incrementing, not just historical. 2. Check both ends of the link. Receive-side errors usually point to the signal arriving on that side, not necessarily the port reporting the error. 3. Replace patch cable or clean/replace fiber and optics. 4. Confirm speed/duplex settings match on both sides. 5. Check logs for flap events around the same timestamp. Drops 1. Separate input drops from output drops. 2. Compare interface rate against capacity. 3. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills affaan-m/network-interface-health--b7955b