fix: increase check time and add random wait to avoid service collisions #1611
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CodSpeed Performance ReportMerging #1611 will not alter performanceComparing Summary
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## master #1611 +/- ##
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Coverage 99.76% 99.76%
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Files 33 33
Lines 3399 3401 +2
Branches 461 461
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+ Hits 3391 3393 +2
Misses 5 5
Partials 3 3 ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
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Tested on a few systems. Everything working as expected. It take a bit longer, but thats expected and worth the tradeoff. |
bdraco
approved these changes
Sep 5, 2025
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Problem
Service registration conflicts were occurring frequently on WiFi networks and with slow IoT devices. The probe responses from existing services weren't arriving within the default 175ms check window, causing false positives for available names and subsequent conflicts.
Solution
This PR improves mDNS service registration reliability by implementing two RFC 6762 recommended timing adjustments:
Random startup delay (RFC 6762, Section 8.1): Added a random 150-250ms delay before sending the first probe query to avoid the "thundering herd" problem when multiple services start simultaneously
Increased check interval: Extended
_CHECK_TIMEfrom 175ms to 500ms to accommodate slower WiFi and IoT devices while remaining RFC-compliant (the RFC specifies "should" for 250ms intervals, allowing flexibility for network conditions)Changes
src/zeroconf/const.py: Increased_CHECK_TIMEfrom 175ms to 500mssrc/zeroconf/_core.py: Added random 150-250ms initial delay before first probe (line 551)Impact
Testing
Verified with:
dns-sdagainst Linuxavahi-daemonFixes service registration reliability issues reported when running development instances over WiFi.