Hi James.To the best of my knowledge, your options include Darwin firewall and HAProxy - geoip.

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Just wondering if there is a way to have Stunnel not accept connection from certain IPs?

stunnel -version stunnel 5.56 on x86_64-apple-darwin18.7.0 platform Threading:PTHREAD Sockets:POLL,IPv6 TLS:ENGINE,FIPS,OCSP,PSK,SNI