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# This TLSv1.2 only
SSLProtocol TLSv1.2
Just check your Apache and OpenSSL version TLSv1.3 is now supported in Apache2 version 2.4.36 with OpenSSL 1.1.1.
This is how my ssl.conf looks like:
<IfModule mod_ssl.c>
# Pseudo Random Number Generator (PRNG):
# Configure one or more sources to seed the PRNG of the SSL library.
# The seed data should be of good random quality.
# WARNING! On some platforms /dev/random blocks if not enough entropy
# is available. This means you then cannot use the /dev/random device
# because it would lead to very long connection times (as long as
# it requires to make more entropy available). But usually those
# platforms additionally provide a /dev/urandom device which doesn't
# block. So, if available, use this one instead. Read the mod_ssl User
# Manual for more details.
#
SSLRandomSeed startup builtin
SSLRandomSeed startup file:/dev/urandom 512
SSLRandomSeed connect builtin
SSLRandomSeed connect file:/dev/urandom 512
##
## SSL Global Context
##
## All SSL configuration in this context applies both to
## the main server and all SSL-enabled virtual hosts.
##
#
# Some MIME-types for downloading Certificates and CRLs
#
AddType application/x-x509-ca-cert .crt
AddType application/x-pkcs7-crl .crl
# Pass Phrase Dialog:
# Configure the pass phrase gathering process.
# The filtering dialog program (`builtin' is a internal
# terminal dialog) has to provide the pass phrase on stdout.
SSLPassPhraseDialog exec:/usr/share/apache2/ask-for-passphrase
# Inter-Process Session Cache:
# Configure the SSL Session Cache: First the mechanism
# to use and second the expiring timeout (in seconds).
# (The mechanism dbm has known memory leaks and should not be used).
#SSLSessionCache dbm:${APACHE_RUN_DIR}/ssl_scache
SSLSessionCache shmcb:${APACHE_RUN_DIR}/ssl_scache(512000)
SSLSessionCacheTimeout 300
# Semaphore:
# Configure the path to the mutual exclusion semaphore the
# SSL engine uses internally for inter-process synchronization.
# (Disabled by default, the global Mutex directive consolidates by default
# this)
#Mutex file:${APACHE_LOCK_DIR}/ssl_mutex ssl-cache
# SSL Cipher Suite:
# List the ciphers that the client is permitted to negotiate. See the
# ciphers(1) man page from the openssl package for list of all available
# options.
# Enable only secure ciphers:
# SSLCipherSuite HIGH:!aNULL
SSLCipherSUite "ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:DHE-RSA-AES256-GCM-SHA384"
# Needs for IE11/WinPhone 8.1 :ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256
# SSLCipherSUite "ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384"
# SSL server cipher order preference:
# Use server priorities for cipher algorithm choice.
# Clients may prefer lower grade encryption. You should enable this
# option if you want to enforce stronger encryption, and can afford
# the CPU cost, and did not override SSLCipherSuite in a way that puts
# insecure ciphers first.
# Default: Off
SSLHonorCipherOrder on
# The protocols to enable.
# Available values: all, SSLv3, TLSv1, TLSv1.1, TLSv1.2
# SSL v2 is no longer supported
#SSLProtocol all -SSLv3
SSLProtocol +TLSv1.2 +TLSv1.3
#Allow insecure renegotiation with clients which do not yet support the
#secure renegotiation protocol. Default: Off
#SSLInsecureRenegotiation on
#Whether to forbid non-SNI clients to access name based virtual hosts.
#Default: Off
#SSLStrictSNIVHostCheck On
SSLUseStapling on
SSLStaplingResponderTimeout 5
SSLStaplingReturnResponderErrors off
SSLStaplingCache shmcb:/var/run/ocsp(128000)
SSLOpenSSLConfCmd Curves secp384r1
SSLOpenSSLConfCmd DHParameters "/etc/ssl/certs/dhparam.pem"
</IfModule>