jDnsProxy

Simple fast and lightweight DNS proxy and cache that listens on TCP or UDP ports and relays the request to various upstream DNS-over-TCP, DNS-over-TLS, or DNS-over-HTTPS servers, optionally over http or socks proxies (like tor), and optionally pinning public keys for complete TLS security. Implements a simple response cache respecting TTLs but also implementing proper Serve-Stale functionality.

This should support any current and future DNS record generically, as well as providing full DNSSEC support if upstream resolvers do.

Sample/default configuration is in jdnsproxy.properties and should be documented clearly there.

Build/run like so:

mvn clean package
java -jar target/jDnsProxy.jar ./jdnsproxy.properties

Implemented specs:

• RFC-1035: DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION
• RFC-7858: Specification for DNS over Transport Layer Security (TLS)
• Draft: DNS Queries over HTTPS
• Draft: Serving Stale Data to Improve DNS Resiliency
• RFC-6891: Extension Mechanisms for DNS (EDNS(0))
• DNS EDNS0 Option Codes (OPT)
• RFC-3225: Indicating Resolver Support of DNSSEC

Use these for quick testing:

dig -p5353 @127.0.0.1 debian.org +tries=1 +retry=0 +tcp
dig -p5353 @127.0.0.1 debian.org +tries=1 +retry=0 +tcp +dnssec

dig -p5353 @127.0.0.1 debian.org +tries=1 +retry=0
dig -p5353 @127.0.0.1 debian.org +tries=1 +retry=0 +dnssec

And use this to extract TLS public keys in pinning format:

openssl s_client -connect 'dns.google.com:443' 2>&1 < /dev/null | sed -n '/-----BEGIN/,/-----END/p' | openssl x509 -noout -pubkey | openssl asn1parse -noout -inform pem -out /dev/stdout | openssl dgst -sha256 -binary | openssl base64

License

GNU/GPLv3 for now, ping me if you think it should be something else, I don't care much.