Am 20.05.2014 15:11, schrieb Colin Fowler: > Is it not true though that allowing weak features merely > gives the illusion of security? It could be argued that a > weak method is technically no better than no encryption
not in reality with no encryption at all any boy sharing the same WLAN is able to read your unencrypted passwords and content with *any* sniffer in case of weak encrypted content at least it needs a minimum of technical knowledge and real interest the difference between "real interest" and "i got served the content for free" may make the difference > so removing the weak method just removes the illusion > (which some would say was a gain) which illusion? if you disable any weak encryption and the delivering server falls back to plaintext you gained nothing nor will any enduser ever know about it >> In an upcoming Postfix 2.12 snapshot, I will change the definition >> of tls_export_cipherlist to by default exclude "EXPORT" and "LOW" >> ciphers, you can achieve the same effect now by setting: >> >> smtp_tls_exclude_ciphers = EXPORT, LOW >> smtpd_tls_exclude_ciphers = EXPORT, LOW >> >> The reason this is safe, is that fortunately there are no longer >> any systems that are not capable of using one of the stronger >> ciphersuites, at least RC4-128 or 3DES. >> >> Most other "hardening" configuration changes are likely to reduce, >> rather than improve SMTP transport security. > > I've heard anecdotes of clients not using the best mutually supported > encryption and instead just using whatever's > first in the list of methods accepted by the server. I don't have anything to > back this up though. Ever heard of > this? If this was true, then disabling weak methods might be beneficial. depends on the client if the client is postfix devliver a message a remote postfix it looks completly different, the selected encryption below is from one postfix supporting SSL3 to another one supporting SSL3 and it selected the currently best available one TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384
