Why has my webserver a higher load now that I run SSL there?
[L] Because SSL uses strong cryptographic encryption and this needs a lot of number crunching. And because when you request a webpage via HTTPS even the images are transfered encrypted. So, when you have a lot of HTTPS traffic the load increases. • Often HTTPS connections to my server require up to 30 seconds for establishing the connection, although sometimes it works faster? [L] Usually this is caused by using a /dev/random device for SSLRandomSeed which is blocking in read(2) calls if not enough entropy is available. Read more about this problem in the refernce chapter under SSLRandomSeed. • What SSL Ciphers are supported by mod_ssl? [L] Usually just all SSL ciphers which are supported by the version of OpenSSL in use (can depend on the way you built OpenSSL). Typically this at least includes the following: • RC4 with MD5 • RC4 with MD5 (export version restricted to 40-bit key) • RC2 with MD5 • RC2 with MD5 (export version restricted to 40-bit key) • IDEA with MD5 • DES with MD5 • T
