Andreas WredeandClaude Sonnet 5
09259eb6cc
Root cause of the flow-selective IPv6 heartbeat loss investigated 2026-07-12/13: Ubuntu ships /usr/lib/sysctl.d/55-ipv6-privacy.conf with use_tempaddr=2 system-wide. Nothing on wlan0 overrode it before this morning's netplan fix, so the interface carried a rotating privacy address alongside the stable one. hbc's long-lived flow eventually straddled a temp-address deprecation event mid-flight, which looked exactly like random upstream packet loss (in-transit, IPv6-only, flow-selective) and cost a day of packet captures before the cause turned out to be this default fighting the WAN config instead. The netplan/NM ipv6.ip6-privacy=false fix already forces this per connection, but that's a timing-dependent override racing a package default. This makes it explicit and permanent: 99- loads after (and wins over) 55- the next time sysctl --system runs. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
13 lines
686 B
Plaintext
13 lines
686 B
Plaintext
net.ipv4.ip_forward=1
|
|
|
|
# Ubuntu ships /usr/lib/sysctl.d/55-ipv6-privacy.conf with use_tempaddr=2
|
|
# (prefer rotating privacy addresses) system-wide. That default fought the
|
|
# WAN uplinks' need for one stable IPv6 source address per interface (hbc,
|
|
# DNS, van-failover all key off it) — a long-lived flow using a source
|
|
# address that later got deprecated mid-flight looked like random upstream
|
|
# packet loss and cost a day of packet-capture debugging (2026-07-12/13)
|
|
# before the cause turned out to be this file loading before ours. 99- beats
|
|
# 55- lexically so this wins the second `sysctl --system` re-reads it.
|
|
net.ipv6.conf.all.use_tempaddr=0
|
|
net.ipv6.conf.default.use_tempaddr=0
|