On Sat, 18 Sep 2021, [email protected] via Exim-users wrote:
I use testssl.sh (https://testssl.sh/) to verify my configuration
(as there is nothing handy like the Qualys Test for HTTPS, IMHO).
Hardenize https://www.hardenize.com/ is not bad.
Testing robust (perfect) forward secrecy, (P)FS -- omitting Null
Authentication/Encryption, 3DES, RC4
PFS is offered (OK) TLS_AES_256_GCM_SHA384
TLS_CHACHA20_POLY1305_SHA256 ECDHE-RSA-AES256-GCM-SHA384
ECDHE-RSA-CHACHA20-POLY1305 TLS_AES_128_GCM_SHA256 TLS_AES_128_CCM_SHA256
ECDHE-RSA-AES128-GCM-SHA256
Elliptic curves offered: prime256v1 secp384r1 secp521r1 X25519 X448
Finite field group: ffdhe2048 ffdhe3072 ffdhe4096 ffdhe6144 ffdhe8192
Testing server preferences
Has server cipher order? yes (OK) -- TLS 1.3 and below
Negotiated protocol TLSv1.3
Negotiated cipher TLS_AES_256_GCM_SHA384, 256 bit ECDH (P-256)
Cipher order
TLSv1.2: ECDHE-RSA-AES256-GCM-SHA384 ECDHE-RSA-CHACHA20-POLY1305
ECDHE-RSA-AES128-GCM-SHA256 AES256-GCM-SHA384 AES256-CCM AES128-GCM-SHA256
AES128-CCM
TLSv1.3: TLS_AES_256_GCM_SHA384 TLS_CHACHA20_POLY1305_SHA256
TLS_AES_128_GCM_SHA256 TLS_AES_128_CCM_SHA256
Besides this: About 85% of the incoming traffic is still unencrypted
(for my statistics, mainly because some high volume mailing list
servers do not use TLS), about 10% uses TLS1.3, 5% still uses TLS1.2
(I log TLS ciphers via +tls_cipher in Exim).
It looks as though you do not allow TLSv1.1 - I suspect that a
substantial faction of that 85% would use it if you allowed it.
For email it is probably better to allow TLSv1.1 than reject it
and end up receiving the message in plain.
--
Andrew C. Aitchison Kendal, UK
[email protected]
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