1
Diagnostic step 1
Collect packet captures on an affected 2.4 GHz client and on the AP (or a mirrored port) during a failure window; capture IGMP/mDNS/multicast and DHCP traffic (use tcpdump -i wlan0 port 5353 or equivalent)
FULL AI ANALYSIS
Intermittent DNS failures for local hostnames on 2.4 GHz Wi‑Fi only
Generated Oct 3, 2026, 12:35:03 AM
Analysis summary
Symptoms point to multicast service discovery or local name announcement loss isolated to 2.4 GHz clients. Correlation with frequent re‑associations suggests a wireless layer problem (packet loss, multicast handling, or client power management) but DHCP and upstream DNS working implies name resolution for local hostnames (mDNS/LLMNR) is affected. Differences by band and persistence after firmware updates suggest AP or radio configuration rather than host daemon bugs.
Possible causes
2.4 GHz radio instability causing packet loss or frequent reassociation breaking mDNS timing
90%AP dropping or throttling multicast/mDNS between 2.4 GHz clients (multicast-to-unicast conversion misconfigured)
75%ARP cache or DNS caching on the AP incorrectly associating hostnames to stale MACs for 2.4 GHz clients
20%Power/save features on mobile clients (Wi‑Fi sleep) suppressing mDNS announcements on 2.4 GHz due to different driver behavior
15%Suggested fixes
2
Diagnostic step 2
Enable verbose wireless logs on the AP temporarily and look for disassociation/reassociation events; correlate timestamps with name resolution failures
3
Diagnostic step 3
Temporarily force an affected client to use a static IP and manually query mDNS with avahi-resolve to test whether multicast responses are received
4
Diagnostic step 4
Disable any AP 'multicast to unicast' or IGMP snooping features for 30 minutes to see if multicast delivery improves (reversible in AP UI)
5
Diagnostic step 5
If packet captures show missing mDNS responses, try configuring one authoritative local unicast DNS on the router (static host entries) as a mitigation while investigating multicast behavior; collect and save the diagnostic captures and AP logs for escalation to vendor support if hardware/firmware multicast handling appears faulty