Engineering

3 Heretic investigations tagged Engineering. Each carries its experiment and a hashed reproduction archive.

20 Sep 2026

A tunnel endpoint is not always a TCP endpoint

An IP-in-IP packet experiment compares forwarding with TCP termination on the same delayed link.

Network measurements Engineering 6 min read

65.203 ms Median origin SYN→ACK, forwarded IPIP, 30 ms link delay

0.028 ms Median origin SYN→ACK, relay through IPIP, 30 ms link delay

13 Sep 2026

Twilio Verify and Heretic: what a successful challenge proves

A cost and protocol comparison of SMS verification and network-informed mobile escalation, with executable pricing and measurement-commitment examples.

Verification Engineering 9 min read

$130 Heretic Signal, computed for 100,000 probes and 10,000 ceremonies

$583 Twilio Verify SMS, computed for 10,000 verifications and 10,000 messages

13 Sep 2026

Whose round trip did you measure?

A packet experiment separates a terminating proxy’s TCP handshake from the browser’s application response, with a direct-client counterexample.

Network measurements Engineering 7 min read

0.009875 ms Median origin SYN→ACK, relay waits 150 ms each way

306.497 ms Median application echo, relay waits 150 ms each way

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