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Postfix - Only use modern and secure ciphers
With the change of tls_medium_cipherlist
, the number of available ciphers for TLSv1.2 will be reduced from 59 to 9 (as per testssl.sh results). The smtpd_tls_mandatory_ciphers
setting will be updated to 'medium' to accommodate the new custom list.
The cipher list will change as follows:
Current Cipher List:
TLSv1.2 (server order)
xc02c ECDHE-ECDSA-AES256-GCM-SHA384 ECDH 253 AESGCM 256 TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
xc030 ECDHE-RSA-AES256-GCM-SHA384 ECDH 253 AESGCM 256 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
x9f DHE-RSA-AES256-GCM-SHA384 DH 4096 AESGCM 256 TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
xcca9 ECDHE-ECDSA-CHACHA20-POLY1305 ECDH 253 ChaCha20 256 TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
xcca8 ECDHE-RSA-CHACHA20-POLY1305 ECDH 253 ChaCha20 256 TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
xccaa DHE-RSA-CHACHA20-POLY1305 DH 4096 ChaCha20 256 TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256
xc0af ECDHE-ECDSA-AES256-CCM8 ECDH 253 AESCCM8 256 TLS_ECDHE_ECDSA_WITH_AES_256_CCM_8
xc0ad ECDHE-ECDSA-AES256-CCM ECDH 253 AESCCM 256 TLS_ECDHE_ECDSA_WITH_AES_256_CCM
xc0a3 DHE-RSA-AES256-CCM8 DH 4096 AESCCM8 256 TLS_DHE_RSA_WITH_AES_256_CCM_8
xc09f DHE-RSA-AES256-CCM DH 4096 AESCCM 256 TLS_DHE_RSA_WITH_AES_256_CCM
xc05d ECDHE-ECDSA-ARIA256-GCM-SHA384 ECDH 253 ARIAGCM 256 TLS_ECDHE_ECDSA_WITH_ARIA_256_GCM_SHA384
xc061 ECDHE-ARIA256-GCM-SHA384 ECDH 253 ARIAGCM 256 TLS_ECDHE_RSA_WITH_ARIA_256_GCM_SHA384
xc053 DHE-RSA-ARIA256-GCM-SHA384 DH 4096 ARIAGCM 256 TLS_DHE_RSA_WITH_ARIA_256_GCM_SHA384
xc024 ECDHE-ECDSA-AES256-SHA384 ECDH 253 AES 256 TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
xc028 ECDHE-RSA-AES256-SHA384 ECDH 253 AES 256 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
x6b DHE-RSA-AES256-SHA256 DH 4096 AES 256 TLS_DHE_RSA_WITH_AES_256_CBC_SHA256
xc073 ECDHE-ECDSA-CAMELLIA256-SHA384 ECDH 253 Camellia 256 TLS_ECDHE_ECDSA_WITH_CAMELLIA_256_CBC_SHA384
xc077 ECDHE-RSA-CAMELLIA256-SHA384 ECDH 253 Camellia 256 TLS_ECDHE_RSA_WITH_CAMELLIA_256_CBC_SHA384
xc4 DHE-RSA-CAMELLIA256-SHA256 DH 4096 Camellia 256 TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA256
xc00a ECDHE-ECDSA-AES256-SHA ECDH 253 AES 256 TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
xc014 ECDHE-RSA-AES256-SHA ECDH 253 AES 256 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
x39 DHE-RSA-AES256-SHA DH 4096 AES 256 TLS_DHE_RSA_WITH_AES_256_CBC_SHA
x88 DHE-RSA-CAMELLIA256-SHA DH 4096 Camellia 256 TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA
x9d AES256-GCM-SHA384 RSA AESGCM 256 TLS_RSA_WITH_AES_256_GCM_SHA384
xc0a1 AES256-CCM8 RSA AESCCM8 256 TLS_RSA_WITH_AES_256_CCM_8
xc09d AES256-CCM RSA AESCCM 256 TLS_RSA_WITH_AES_256_CCM
xc051 ARIA256-GCM-SHA384 RSA ARIAGCM 256 TLS_RSA_WITH_ARIA_256_GCM_SHA384
x3d AES256-SHA256 RSA AES 256 TLS_RSA_WITH_AES_256_CBC_SHA256
xc0 CAMELLIA256-SHA256 RSA Camellia 256 TLS_RSA_WITH_CAMELLIA_256_CBC_SHA256
x35 AES256-SHA RSA AES 256 TLS_RSA_WITH_AES_256_CBC_SHA
x84 CAMELLIA256-SHA RSA Camellia 256 TLS_RSA_WITH_CAMELLIA_256_CBC_SHA
xc02b ECDHE-ECDSA-AES128-GCM-SHA256 ECDH 253 AESGCM 128 TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
xc02f ECDHE-RSA-AES128-GCM-SHA256 ECDH 253 AESGCM 128 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
x9e DHE-RSA-AES128-GCM-SHA256 DH 4096 AESGCM 128 TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
xc0ae ECDHE-ECDSA-AES128-CCM8 ECDH 253 AESCCM8 128 TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8
xc0ac ECDHE-ECDSA-AES128-CCM ECDH 253 AESCCM 128 TLS_ECDHE_ECDSA_WITH_AES_128_CCM
xc0a2 DHE-RSA-AES128-CCM8 DH 4096 AESCCM8 128 TLS_DHE_RSA_WITH_AES_128_CCM_8
xc09e DHE-RSA-AES128-CCM DH 4096 AESCCM 128 TLS_DHE_RSA_WITH_AES_128_CCM
xc05c ECDHE-ECDSA-ARIA128-GCM-SHA256 ECDH 253 ARIAGCM 128 TLS_ECDHE_ECDSA_WITH_ARIA_128_GCM_SHA256
xc060 ECDHE-ARIA128-GCM-SHA256 ECDH 253 ARIAGCM 128 TLS_ECDHE_RSA_WITH_ARIA_128_GCM_SHA256
xc052 DHE-RSA-ARIA128-GCM-SHA256 DH 4096 ARIAGCM 128 TLS_DHE_RSA_WITH_ARIA_128_GCM_SHA256
xc023 ECDHE-ECDSA-AES128-SHA256 ECDH 253 AES 128 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
xc027 ECDHE-RSA-AES128-SHA256 ECDH 253 AES 128 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
x67 DHE-RSA-AES128-SHA256 DH 4096 AES 128 TLS_DHE_RSA_WITH_AES_128_CBC_SHA256
xc072 ECDHE-ECDSA-CAMELLIA128-SHA256 ECDH 253 Camellia 128 TLS_ECDHE_ECDSA_WITH_CAMELLIA_128_CBC_SHA256
xc076 ECDHE-RSA-CAMELLIA128-SHA256 ECDH 253 Camellia 128 TLS_ECDHE_RSA_WITH_CAMELLIA_128_CBC_SHA256
xbe DHE-RSA-CAMELLIA128-SHA256 DH 4096 Camellia 128 TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA256
xc009 ECDHE-ECDSA-AES128-SHA ECDH 253 AES 128 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
xc013 ECDHE-RSA-AES128-SHA ECDH 253 AES 128 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
x33 DHE-RSA-AES128-SHA DH 4096 AES 128 TLS_DHE_RSA_WITH_AES_128_CBC_SHA
x45 DHE-RSA-CAMELLIA128-SHA DH 4096 Camellia 128 TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA
x9c AES128-GCM-SHA256 RSA AESGCM 128 TLS_RSA_WITH_AES_128_GCM_SHA256
xc0a0 AES128-CCM8 RSA AESCCM8 128 TLS_RSA_WITH_AES_128_CCM_8
xc09c AES128-CCM RSA AESCCM 128 TLS_RSA_WITH_AES_128_CCM
xc050 ARIA128-GCM-SHA256 RSA ARIAGCM 128 TLS_RSA_WITH_ARIA_128_GCM_SHA256
x3c AES128-SHA256 RSA AES 128 TLS_RSA_WITH_AES_128_CBC_SHA256
xba CAMELLIA128-SHA256 RSA Camellia 128 TLS_RSA_WITH_CAMELLIA_128_CBC_SHA256
x2f AES128-SHA RSA AES 128 TLS_RSA_WITH_AES_128_CBC_SHA
x41 CAMELLIA128-SHA RSA Camellia 128 TLS_RSA_WITH_CAMELLIA_128_CBC_SHA
TLSv1.3 (server order)
x1302 TLS_AES_256_GCM_SHA384 ECDH 253 AESGCM 256 TLS_AES_256_GCM_SHA384
x1303 TLS_CHACHA20_POLY1305_SHA256 ECDH 253 ChaCha20 256 TLS_CHACHA20_POLY1305_SHA256
x1301 TLS_AES_128_GCM_SHA256 ECDH 253 AESGCM 128 TLS_AES_128_GCM_SHA256
New Cipher List:
TLSv1.2 (server order)
xc02b ECDHE-ECDSA-AES128-GCM-SHA256 ECDH 253 AESGCM 128 TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
xc02f ECDHE-RSA-AES128-GCM-SHA256 ECDH 253 AESGCM 128 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
xc02c ECDHE-ECDSA-AES256-GCM-SHA384 ECDH 253 AESGCM 256 TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
xc030 ECDHE-RSA-AES256-GCM-SHA384 ECDH 253 AESGCM 256 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
xcca9 ECDHE-ECDSA-CHACHA20-POLY1305 ECDH 253 ChaCha20 256 TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
xcca8 ECDHE-RSA-CHACHA20-POLY1305 ECDH 253 ChaCha20 256 TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
x9e DHE-RSA-AES128-GCM-SHA256 DH 4096 AESGCM 128 TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
x9f DHE-RSA-AES256-GCM-SHA384 DH 4096 AESGCM 256 TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
xccaa DHE-RSA-CHACHA20-POLY1305 DH 4096 ChaCha20 256 TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256
TLSv1.3 (server order)
x1302 TLS_AES_256_GCM_SHA384 ECDH 253 AESGCM 256 TLS_AES_256_GCM_SHA384
x1303 TLS_CHACHA20_POLY1305_SHA256 ECDH 253 ChaCha20 256 TLS_CHACHA20_POLY1305_SHA256
x1301 TLS_AES_128_GCM_SHA256 ECDH 253 AESGCM 128 TLS_AES_128_GCM_SHA256
Testing the change
To test the changes on your system, install testssl.sh and run:
testssl -t smtp mailcow.your.tld:25
During tests on my server, only scanning bots failed to connect to the SMTP server.