X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/883335dc3231d56603fb097057f585d3f165bbba..83da1223921fe30362e8374951360dcc8f21c4e7:/doc/doc-txt/NewStuff diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff index e61421830..9cc8f81cc 100644 --- a/doc/doc-txt/NewStuff +++ b/doc/doc-txt/NewStuff @@ -1,4 +1,4 @@ -$Cambridge: exim/doc/doc-txt/NewStuff,v 1.125 2006/12/20 09:44:37 ph10 Exp $ +$Cambridge: exim/doc/doc-txt/NewStuff,v 1.128 2007/01/18 15:35:42 ph10 Exp $ New Features in Exim -------------------- @@ -8,6 +8,185 @@ Before a formal release, there may be quite a lot of detail so that people can test from the snapshots or the CVS before the documentation is updated. Once the documentation is updated, this file is reduced to a short list. +Version 4.67 +------------ + + 1. There is a new log selector called smtp_no_mail, which is not included in + the default setting. When it is set, a line is written to the main log + whenever an accepted SMTP connection terminates without having issued a + MAIL command. This includes both the case when the connection is dropped, + and the case when QUIT is used. Note that it does not include cases where + the connection is rejected right at the start (by an ACL, or because there + are too many connections, or whatever). These cases already have their own + log lines. + + The log line that is written contains the identity of the client in the + usual way, followed by D= and a time, which records the duration of the + connection. If the connection was authenticated, this fact is logged + exactly as it is for an incoming message, with an A= item. If the + connection was encrypted, CV=, DN=, and X= items may appear as they do for + an incoming message, controlled by the same logging options. + + Finally, if any SMTP commands were issued during the connection, a C= item + is added to the line, listing the commands that were used. For example, + + C=EHLO,QUIT + + shows that the client issued QUIT straight after EHLO. If there were fewer + than 20 commands, they are all listed. If there were more than 20 commands, + the last 20 are listed, preceded by "...". However, with the default + setting of 10 for smtp_accep_max_nonmail, the connection will in any case + be aborted before 20 non-mail commands are processed. + + 2. When an item in a dnslists list is followed by = and & and a list of IP + addresses, in order to restrict the match to specific results from the DNS + lookup, the behaviour was not clear when the lookup returned more than one + IP address. For example, consider the condition + + dnslists = a.b.c=127.0.0.1 + + What happens if the DNS lookup for the incoming IP address yields both + 127.0.0.1 and 127.0.0.2 by means of two separate DNS records? Is the + condition true because at least one given value was found, or is it false + because at least one of the found values was not listed? And how does this + affect negated conditions? + + The behaviour of = and & has not been changed; however, the text below + documents it more clearly. In addition, two new additional conditions (== + and =&) have been added, to permit the "other" behaviour to be configured. + + A DNS lookup may yield more than one record. Thus, the result of the lookup + for a dnslists check may yield more than one IP address. The question then + arises as to whether all the looked up addresses must be listed, or whether + just one is good enough. Both possibilities are provided for: + + . If = or & is used, the condition is true if any one of the looked up + IP addresses matches one of the listed addresses. Consider: + + dnslists = a.b.c=127.0.0.1 + + If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is + true because 127.0.0.1 matches. + + . If == or =& is used, the condition is true only if every one of the + looked up IP addresses matches one of the listed addresses. Consider: + + dnslists = a.b.c==127.0.0.1 + + If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is + false because 127.0.0.2 is not listed. You would need to have + + dnslists = a.b.c==127.0.0.1,127.0.0.2 + + for the condition to be true. + + When ! is used to negate IP address matching, it inverts the result, giving + the precise opposite of the behaviour above. Thus: + + . If != or !& is used, the condition is true if none of the looked up IP + addresses matches one of the listed addresses. Consider: + + dnslists = a.b.c!&0.0.0.1 + + If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is + false because 127.0.0.1 matches. + + . If !== or !=& is used, the condition is true there is at least one looked + up IP address that does not match. Consider: + + dnslists = a.b.c!=&0.0.0.1 + + If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is + true, because 127.0.0.2 does not match. You would need to have + + dnslists = a.b.c!=&0.0.0.1,0.0.0.2 + + for the condition to be false. + + When the DNS lookup yields only a single IP address, there is no difference + between = and == and between & and =&. + + 3. Up till now, the only control over which cipher suites GnuTLS uses has been + for the cipher algorithms. New options have been added to allow some of the + other parameters to be varied. Here is complete documentation for the + available features: + + GnuTLS allows the caller to specify separate lists of permitted key + exchange methods, main cipher algorithms, and MAC algorithms. These may be + used in any combination to form a specific cipher suite. This is unlike + OpenSSL, where complete cipher names can be passed to its control function. + GnuTLS also allows a list of acceptable protocols to be supplied. + + For compatibility with OpenSSL, the tls_require_ciphers option can be set + to complete cipher suite names such as RSA_ARCFOUR_SHA, but for GnuTLS this + option controls only the cipher algorithms. Exim searches each item in the + list for the name of an available algorithm. For example, if the list + contains RSA_AES_SHA, then AES is recognized, and the behaviour is exactly + the same as if just AES were given. + + There are additional options called gnutls_require_kx, gnutls_require_mac, + and gnutls_require_protocols that can be used to restrict the key exchange + methods, MAC algorithms, and protocols, respectively. These options are + ignored if OpenSSL is in use. + + All four options are available as global options, controlling how Exim + behaves as a server, and also as options of the smtp transport, controlling + how Exim behaves as a client. All the values are string expanded. After + expansion, the values must be colon-separated lists, though the separator + can be changed in the usual way. + + Each of the four lists starts out with a default set of algorithms. If the + first item in one of the "require" options does _not_ start with an + exclamation mark, all the default items are deleted. In this case, only + those that are explicitly specified can be used. If the first item in one + of the "require" items _does_ start with an exclamation mark, the defaults + are left on the list. + + Then, any item that starts with an exclamation mark causes the relevant + entry to be removed from the list, and any item that does not start with an + exclamation mark causes a new entry to be added to the list. Unrecognized + items in the list are ignored. Thus: + + tls_require_ciphers = !ARCFOUR + + allows all the defaults except ARCFOUR, whereas + + tls_require_ciphers = AES : 3DES + + allows only cipher suites that use AES or 3DES. For tls_require_ciphers + the recognized names are AES_256, AES_128, AES (both of the preceding), + 3DES, ARCFOUR_128, ARCFOUR_40, and ARCFOUR (both of the preceding). The + default list does not contain all of these; it just has AES_256, AES_128, + 3DES, and ARCFOUR_128. + + For gnutls_require_kx, the recognized names are DHE_RSA, RSA (which + includes DHE_RSA), DHE_DSS, and DHE (which includes both DHE_RSA and + DHE_DSS). The default list contains RSA, DHE_DSS, DHE_RSA. + + For gnutls_require_mac, the recognized names are SHA (synonym SHA1), and + MD5. The default list contains SHA, MD5. + + For gnutls_require_protocols, the recognized names are TLS1 and SSL3. + The default list contains TLS1, SSL3. + + In a server, the order of items in these lists is unimportant. The server + will advertise the availability of all the relevant cipher suites. However, + in a client, the order in the tls_require_ciphers list specifies a + preference order for the cipher algorithms. The first one in the client's + list that is also advertised by the server is tried first. + + +Version 4.66 +------------ + +No new features were added to 4.66. + + +Version 4.65 +------------ + +No new features were added to 4.65. + Version 4.64 ------------