ET INFO Tailscale DERP Relay Server in TLS SNI

Query · suricata

flow:established,to_server;
tls.sni;
content:"derp"; startswith;
content:".tailscale.com"; fast_pattern; endswith;
pcre:"/derp\d+[a-z]?\x2etailscale.com/";
Raw source ET INFO Tailscale DERP Relay Server in TLS SNI · Suricata
Esc
Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert tls $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET INFO Tailscale DERP Relay Server in TLS SNI";
    flow:established,to_server;
    tls.sni;
    content:"derp"; startswith;
    content:".tailscale.com"; fast_pattern; endswith;
    pcre:"/derp\d+[a-z]?\x2etailscale.com/";
    reference:url,tailscale.com/docs/reference/derp-servers;
    classtype:misc-activity;
    sid:2071656; rev:1;
    metadata:created_at 2026_08_20, deployment Perimeter, confidence High, signature_severity Informational, updated_at 2026_08_20;
)

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