Issue:
– WAN failed (partially).
– devices servers reported no internet, hosted services outage.
– (local)unifi console showed online, speedtest would fail.
Setup: UDM Pro, 2 servers running Adguard, and all data on ports 53, 853 only going to the adguard servers.
troubleshooting the problem, i could find:
– ✅ICMP traffic (ping) continued to work.
– ✅DNS over UDP continued to work.
– ✅Packet captures on the WAN interface showed outbound TCP SYN packets but,
– ❌no returning SYN-ACK packets from multiple destinations (Cloudflare 1.1.1.1, AdGuard DNS, Google-hosted services, etc.).
– ✅TCP connections failed to establish.
– ❌ HTTPS failing.
– ❌ DNS-over-TLS failing.
– ✅The WAN IP remained assigned.
– ✅Site-to-site (wireguard) Traffic to remote family LANs still worked.
– ✅The issue was resolved immediately by power-cycling the ISP modem/router operating in bridge mode.
as my knowledge is limited:
– Any suggestions on how to further or better diagnose /prevent this, should this happen again is appreciated.
– Does anyone have a solution on how to set up a fail-over solution that brings all traffic over the site-to-site (wireguard) link to the family home. (should this happen again, atleast i would have 50mpbs connection left).
– To Ubiquiti, maybe find a better way to detect when your connection is down, because the internal console thinks full service remained 24/7.
thanks to anyone taking the time to help.
Source: r/UNIFI · by /u/mysteryliner