• Linux
• OpenSSL

OpenSSL Linux command line ssl tool

• Links smtp , security/ssl , LinuxCurl, easy-rsa , LetsEncrypt

• openssl self signed certificate with keyUsage flags

• Online check cert + chain: https://tools.keycdn.com/ssl

Check cert using docker container

1. $ docker run -it debian bash
2. :/# apt update ; apt install openssl curl ca-certificates dnsutils
3. :/# echo | openssl s_client -showcerts -connect google.com:44

Verify a web server certificate

•  openssl s_client -showcerts -connect my.test.com:443 

  • Output should end on "Verify return code: 0 (ok)"
  • As of 2017 the TLS Protocol should be TLSv1.2 at least.

• For sni you can add -servername xyz.test.com

OpenSSL retrieve url

• retrieve url, e.g. /healthz, note -ign_eof to wait for more input from echo

  time echo -e "GET /healthz HTTP/1.1\r\nConnection: close\r\nHost: pieter\r\n\r\n" |\
   openssl s_client -ign_eof  -connect 172.24.0.3:443

SSL speed testing

• speed testing

  openssl s_time -connect 172.17.0.2:443 -www "/welcome/"
  openssl s_time -connect 172.17.0.2:443 -www /
  
  curl -s -w 'Testing Website Response Time for :%{url_effective}\n\nLookup Time:\t\t%{time_namelookup}\nConnect Time:\t\t%{time_connect}\nPre-transfer Time:\t%{time_pretransfer}\nStart-transfer Time:\t%{time_starttransfer}\n\nTotal Time:\t\t%{time_total}\n' -o /dev/null https://172.17.0.2

• slow

  231 connections in 0.29s; 796.55 connections/user sec, bytes read 57981
  231 connections in 31 real seconds, 251 bytes read per connection

• fast

  30821 connections in 8.14s; 3786.36 connections/user sec, bytes read 6749799
  30821 connections in 31 real seconds, 219 bytes read per connection

• OpenSSL smtp certificate verify https://wiki.vigor.nz/linux/PostFixEmail

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