Hi —
This is postfix 3.0.2 and FreeBSD-10.2/STABLE. I switched from OpenSLL to
LibreSSL some month ago.
My relevant SSL/TLS settings for receiving mail didn't change ever since that
time (postconf -n | grep tls | grep smtpd)
smtpd_use_tls = yes
smtpd_tls_auth_only = yes
smtpd_tls_security_level = may
smtpd_tls_loglevel = 1
smtpd_tls_cert_file = /path-to-pem/my-server.pem
smtpd_tls_key_file = /path-to-pem/my-server.pem
smtpd_tls_security_level = may
smtpd_tls_protocols = !SSLv2 !SSLv3
smtpd_tls_ciphers = medium
smtpd_tls_mandatory_protocols = !SSLv2 !SSLv3
smtpd_tls_mandatory_ciphers = high
smtpd_tls_dh1024_param_file = /path-to-pem/dh-2048.pem
smtpd_tls_dh512_param_file = /path-to-pem/dh-512.pem
After my recent upgrade of LibreSSL to 2.2.2 some servers fail to deliver mail.
Example logfile entry:
postfix/smtpd[111]: connect from xxx.xxx[1.2.3.4]
postfix/smtpd[111]: SSL_accept error from xxx.xxx[1.2.3.4]: lost
connection
postfix/smtpd[111]: lost connection after STARTTLS from
xxx.xxx[1.2.3.4]:
postfix/smtpd[111]: disconnect from xxx.xxx[1.2.3.4]: ehlo=1
starttls=0/1 commands=1/2
Previous LibreSSL 2.2.1: *all* those servers delivered their mail as reported
by logwatch; example:
16 Anonymous: TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)
1 1.2.3.4 xxx.xxx
For the time being I am "helping" myself by discarding TLS for those servers by
setting "1.2.3.4 STARTTLS" in:
smtpd_discard_ehlo_keyword_address_maps =
cidr:/path-to-conf/smtpd_discard_ehlo_keyword_address_maps
But, I do consider this approach somehow error prone. I could revert either to
the previous LibreSSL version or back to OpenSSL, but I really would like to
understand whether I do have an erroneous configuration of postfix, or if I am
missing something else.
In the release notes of LibreSSL 2.2.2
(http://ftp.openbsd.org/pub/OpenBSD/LibreSSL/libressl-2.2.2-relnotes.txt) I do
find:
* Removed SSLv3 support from openssl(1)
But I do find SSLv3 protocol entries:
mail> openssl version
LibreSSL 2.2.2
mail> openssl ciphers -v | grep ^DHE-RSA-AES256-SHA
DHE-RSA-AES256-SHA256 TLSv1.2 Kx=DH Au=RSA Enc=AES(256)
Mac=SHA256
DHE-RSA-AES256-SHA SSLv3 Kx=DH Au=RSA Enc=AES(256) Mac=SHA1
Sigh, I do have to admit that crypto configuration isn't well understood by
myself, thus I feel lost here. But every hint is highly appreciated.
(BTW: is this off-topic for that list? If so, tell me then. I will move to a
recommended ML.)
With kind regards and thanks in advance,
Michael
