We observed a 65% drop in global telnet traffic in a single hour on Jan 14, settling into a sustained 59% reduction. 18 ASNs went silent, 5 countries disappeared, but cloud providers were unaffected.
Our analysis of 51.2M sessions points to backbone-level port 23 filtering by a North American Tier 1 transit provider.
🔗 https://www.labs.greynoise.io/grimoire/2026-02-10-telnet-falls-silent/
