esnitool

A cmdline tool in golang to query and display TLS ESNI records from DNS

Sample Usage

$ ./esnitool www.cloudflare.com
domain: _esni.www.cloudflare.com
version : FF 01 (known)
checksum: B7 EF A8 70 (valid)
keys (1):
  0: x25519 [57 51 54 D0 33 EF BF B8 AB 15 26 F5 E9 42 B8 20 F7 1B 9C D4...]
cipher_suites (1):
  0: TLS_AES_128_GCM_SHA256
padded_length: 260
not_before: 2018-11-19 14:00:00 -0500 EST
not_after: 2018-11-25 14:00:00 -0500 EST
extensions: none

Version

Currently it supports the lastest draft (02). You can be sure there will be changes before it is finalized.

Building

There are no dependencies other than stdlib, so it's just:

cd $GOPATH
go get github.com/mordyovits/esnitool
./bin/esnitool www.cloudflare.com