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Identify duplicate hardware (MAC) addresses on the same network segment. Use when a helper surfaces a concrete duplicate `link/ether` value or an ARP entry that flips between two MACs for one IP.
Codex または Claude でインストール この Prompt をコピーして Codex、Claude、または他のアシスタントに貼り付けると、Skill ページを確認してインストールできます。
SOC 職業分類に基づく
Integration-test skill only. Invoke at the start of every troubleshooting session before other diagnostics to confirm the NIKA skill library is loaded.
Identify ACL and firewall faults from nftables or iptables rules. Use when traffic is selectively blocked by protocol or service (ARP, ICMP, HTTP, DNS, BGP, or packet-size filtering).
Reference list of signals that look suspicious but are normal testbed behavior. Consult before promoting any observation to a symptom.
Identify BGP routing faults — ASN misconfiguration, missing route advertisement, prefix hijacking, blackhole route leak. Use when reachability failures follow BGP-routed paths, BGP sessions fail to establish, or expected prefixes are missing from peers.
Parse oversized MCP tool output. When a tool returns "Output has been saved to <file>.txt" because the result exceeded Claude Code's token limit, run this skill's parser instead of re-reading the file in chunks. Covers `get_reachability` on large topologies and `service_snapshot` on labs with many published hostnames.
Identify DHCP server-side faults — service down, missing subnet declaration, spoofed gateway or DNS pushed by the server. Use when one or more hosts cannot obtain a lease, or hosts received DHCP-supplied values that look wrong.
| name | mac-address-conflict-skill |
| description | Identify duplicate hardware (MAC) addresses on the same network segment. Use when a helper surfaces a concrete duplicate `link/ether` value or an ARP entry that flips between two MACs for one IP. |
mac_address_conflict means two different devices present the same Layer 2 hardware identity on the network.link/ether MAC.python diagnosis-methodology-skill/scripts/l2_snapshot.pypython diagnosis-methodology-skill/scripts/network_inventory.py summarypython diagnosis-methodology-skill/scripts/network_inventory.py connected <device>exec_shell(host_name="<host>", command="ip link show")exec_shell(host_name="<witness_host>", command="arp -n")l2_snapshot is the MAC-inventory and duplicate-MAC proof tool; network_inventory only exposes topology views (summary, connected).link/ether comparison is stronger than ARP-table symptoms.ethX -> br0 is topology information, not MAC-conflict proof by itself.link/ether values on two different routers or hosts are a real L2 identity fault, not a measurement artifact.