Docs: usability of malware ACL condition

[users/jgh/exim.git] / doc / doc-txt / experimental-spec.txt

diff --git a/doc/doc-txt/experimental-spec.txt b/doc/doc-txt/experimental-spec.txt
index 211841f3f0e02dd552519d8539cc365f8959e40d..f748f61460a27692e61ed51630e379ec5c2b156c 100644 (file)
--- a/doc/doc-txt/experimental-spec.txt
+++ b/doc/doc-txt/experimental-spec.txt
@@ -873,84 +873,6 @@ used via the transport in question.
 
 
 
-Early pipelining support
-------------------------
-Ref: https://datatracker.ietf.org/doc/draft-harris-early-pipe/
-
-If compiled with EXPERIMENTAL_PIPE_CONNECT support is included for this feature.
-The server advertises the feature in its EHLO response, currently using the name
-"X_PIPE_CONNECT" (this will change, some time in the future).
-A client may cache this information, along with the rest of the EHLO response,
-and use it for later connections.  Those later ones can send esmtp commands before
-a banner is received.
-
-Up to 1.5 roundtrip times can be taken out of cleartext connections, 2.5 on
-STARTTLS connections.
-
-In combination with the traditional PIPELINING feature the following example
-sequences are possible (among others):
-
-(client)                (server)
-
-EHLO,MAIL,RCPT,DATA ->
-                     <- banner,EHLO-resp,MAIL-ack,RCPT-ack,DATA-goahead
-message-data        ->
-------
-
-EHLO,MAIL,RCPT,BDAT              ->
-                                  <- banner,EHLO-resp,MAIL-ack,RCPT-ack
-message-data                     ->
-------
-
-EHLO,STARTTLS                     ->
-                                   <- banner,EHLO-resp,TLS-goahead
-TLS1.2-client-hello               ->
-                                   <- TLS-server-hello,cert,hello-done
-client-Kex,change-cipher,finished ->
-                                   <- change-cipher,finished
-EHLO,MAIL,RCPT,DATA               ->
-                                   <- EHLO-resp,MAIL-ack,RCPT-ack,DATA-goahead
-
-------
-(tls-on-connect)
-TLS1.2-client-hello               ->
-                                   <- TLS-server-hello,cert,hello-done
-client-Kex,change-cipher,finished ->
-                                   <- change-cipher,finshed
-                                   <- banner
-EHLO,MAIL,RCPT,DATA               ->
-                                   <- EHLO-resp,MAIL-ack,RCPT-ack,DATA-goahead
-
-Where the initial client packet is SMTP, it can combine with the TCP Fast Open
-feature and be sent in the TCP SYN.
-
-
-A main-section option "pipelining_connect_advertise_hosts" (default: *)
-and an smtp transport option "hosts_pipe_connect" (default: unset)
-control the feature.
-
-If the "pipelining" log_selector is enabled, the "L" field in server <=
-log lines has a period appended if the feature was advertised but not used;
-or has an asterisk appended if the feature was used.  In client => lines
-the "L" field has an asterisk appended if the feature was used.
-
-The "retry_data_expire" option controls cache invalidation.
-Entries are also rewritten (or cleared) if the adverised features
-change.
-
-
-NOTE: since the EHLO command must be constructed before the connection is
-made it cannot depend on the interface IP address that will be used.
-Transport configurations should be checked for this.  An example avoidance:
-
- helo_data =   ${if def:sending_ip_address \
-                  {${lookup dnsdb{>! ptr=$sending_ip_address} \
-                       {${sg{$value} {^([^!]*).*\$} {\$1}}} fail}} \
-                  {$primary_hostname}}
-
-
-
-
 TLS Session Resumption
 ----------------------
 TLS Session Resumption for TLS 1.2 and TLS 1.3 connections can be used (defined
@@ -984,7 +906,10 @@ Security aspects:
  vulnarability surface.  An attacker able to decrypt it would have access
  all connections using the resumed session.
  The session ticket encryption key is not committed to storage by the server
- and is rotated regularly.  Tickets have limited lifetime.
+ and is rotated regularly (OpenSSL: 1hr, and one previous key is used for
+ overlap; GnuTLS 6hr but does not specify any overlap).
+ Tickets have limited lifetime (2hr, and new ones issued after 1hr under
+ OpenSSL.  GnuTLS 2hr, appears to not do overlap).
 
  There is a question-mark over the security of the Diffie-Helman parameters
  used for session negotiation. TBD.  q-value; cf bug 1895
@@ -993,17 +918,16 @@ Observability:
  New log_selector "tls_resumption", appends an asterisk to the tls_cipher "X="
  element.
 
- Variables $tls_{in,out}_resumption have bit 0-4 indicating respectively
+ Variables $tls_{in,out}_resumption have bits 0-4 indicating respectively
  support built, client requested ticket, client offered session,
  server issued ticket, resume used.  A suitable decode list is provided
  in the builtin macro _RESUME_DECODE for ${listextract {}{}}.
 
 Issues:
  In a resumed session:
-  $tls_{in,out}_certificate_verified will be unset (undler OpenSSL)
-  verify = certificate will be false (undler OpenSSL)
   $tls_{in,out}_cipher will have values different to the original (under GnuTLS)
-  $tls_{in,out}_ocsp will be "not requested" or "no response"
+  $tls_{in,out}_ocsp will be "not requested" or "no response", and
+   hosts_require_ocsp will fail
 
 
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