DSN: Under EXPERIMENTAL_DSN_INFO add extras to bounce messages. Bug 1686

14 files changed, 498 insertions, 110 deletions

diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index f24883d92..bc95690b1 100644
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -34,6 +34,10 @@ HS/01 Bug 1671: Fix post transport crash.
 JH/03 Bug 425: Capture substrings in $regex1, $regex2 etc from regex &
       mime_regex ACL conditions.
 
+JH/04 Bug 1686: When compiled with EXPERIMENTAL_DSN_INFO: Add extra information
+      to DSN fail messages (bounces): remote IP, remote greeting, remote response
+      to HELO, local diagnostic string.
+
 
 Exim version 4.86
 -----------------
diff --git a/doc/doc-txt/experimental-spec.txt b/doc/doc-txt/experimental-spec.txt
index 317f40101..cf3c27f6a 100644
--- a/doc/doc-txt/experimental-spec.txt
+++ b/doc/doc-txt/experimental-spec.txt
@@ -1380,6 +1380,49 @@ must be representable in UTF-16.
 
 
 
+DSN extra information
+---------------------
+If compiled with EXPERIMENTAL_DSN_INFO extra information will be added
+to DSN fail messages ("bounces"), when available.  The intent is to aid
+tracing of specific failing messages, when presented with a "bounce"
+complaint and needing to search logs.
+
+
+The remote MTA IP address, with port number if nonstandard.
+Example:
+  Remote-MTA: X-ip; [127.0.0.1]:587
+Rationale:
+  Several addresses may correspond to the (already available)
+  dns name for the remote MTA.
+
+The remote MTA connect-time greeting.
+Example:
+  X-Remote-MTA-smtp-greeting: X-str; 220 the.local.host.name ESMTP Exim x.yz Tue, 2 Mar 1999 09:44:33 +0000
+Rationale:
+  This string sometimes presents the remote MTA's idea of its
+  own name, and sometimes identifies the MTA software.
+
+The remote MTA response to HELO or EHLO.
+Example:
+  X-Remote-MTA-helo-response: X-str; 250-the.local.host.name Hello localhost [127.0.0.1]
+Limitations:
+  Only the first line of a multiline response is recorded.
+Rationale:
+  This string sometimes presents the remote MTA's view of
+  the peer IP connecting to it.
+
+The reporting MTA detailed diagnostic.
+Example:
+  X-Exim-Diagnostic: X-str; SMTP error from remote mail server after RCPT TO:<d3@myhost.test.ex>: 550 hard error
+Rationale:
+  This string somtimes give extra information over the
+  existing (already available) Diagnostic-Code field.
+
+
+Note that non-RFC-documented field names and data types are used.
+
+
+
 
 --------------------------------------------------------------
 End of file
diff --git a/src/src/config.h.defaults b/src/src/config.h.defaults
index 596e651f0..6af3b4d43 100644
--- a/src/src/config.h.defaults
+++ b/src/src/config.h.defaults
@@ -172,6 +172,7 @@ it's a default value. */
 #define EXPERIMENTAL_BRIGHTMAIL
 #define EXPERIMENTAL_DANE
 #define EXPERIMENTAL_DCC
+#define EXPERIMENTAL_DSN_INFO
 #define EXPERIMENTAL_DMARC
 #define EXPERIMENTAL_EVENT
 #define EXPERIMENTAL_INTERNATIONAL
diff --git a/src/src/deliver.c b/src/src/deliver.c
index b5aa9b9a7..3f22dc91f 100644
--- a/src/src/deliver.c
+++ b/src/src/deliver.c
@@ -3223,41 +3223,56 @@ while (!done)
       break;
       }
 
-    addr->transport_return = *ptr++;
-    addr->special_action = *ptr++;
-    memcpy(&(addr->basic_errno), ptr, sizeof(addr->basic_errno));
-    ptr += sizeof(addr->basic_errno);
-    memcpy(&(addr->more_errno), ptr, sizeof(addr->more_errno));
-    ptr += sizeof(addr->more_errno);
-    memcpy(&(addr->flags), ptr, sizeof(addr->flags));
-    ptr += sizeof(addr->flags);
-    addr->message = (*ptr)? string_copy(ptr) : NULL;
-    while(*ptr++);
-    addr->user_message = (*ptr)? string_copy(ptr) : NULL;
-    while(*ptr++);
-
-    /* Always two strings for host information, followed by the port number and DNSSEC mark */
-
-    if (*ptr != 0)
+    switch (subid)
       {
-      h = store_get(sizeof(host_item));
-      h->name = string_copy(ptr);
-      while (*ptr++);
-      h->address = string_copy(ptr);
-      while(*ptr++);
-      memcpy(&(h->port), ptr, sizeof(h->port));
-      ptr += sizeof(h->port);
-      h->dnssec = *ptr == '2' ? DS_YES
-		: *ptr == '1' ? DS_NO
-		: DS_UNK;
-      ptr++;
-      addr->host_used = h;
-      }
-    else ptr++;
+#ifdef EXPERIMENTAL_DSN_INFO
+      case '1':	/* must arrive before A0, and applies to that addr */
+      		/* Two strings: smtp_greeting and helo_response */
+	addr->smtp_greeting = string_copy(ptr);
+	while(*ptr++);
+	addr->helo_response = string_copy(ptr);
+	while(*ptr++);
+	break;
+#endif
 
-    /* Finished with this address */
+      case '0':
+	addr->transport_return = *ptr++;
+	addr->special_action = *ptr++;
+	memcpy(&(addr->basic_errno), ptr, sizeof(addr->basic_errno));
+	ptr += sizeof(addr->basic_errno);
+	memcpy(&(addr->more_errno), ptr, sizeof(addr->more_errno));
+	ptr += sizeof(addr->more_errno);
+	memcpy(&(addr->flags), ptr, sizeof(addr->flags));
+	ptr += sizeof(addr->flags);
+	addr->message = (*ptr)? string_copy(ptr) : NULL;
+	while(*ptr++);
+	addr->user_message = (*ptr)? string_copy(ptr) : NULL;
+	while(*ptr++);
 
-    addr = addr->next;
+	/* Always two strings for host information, followed by the port number and DNSSEC mark */
+
+	if (*ptr != 0)
+	  {
+	  h = store_get(sizeof(host_item));
+	  h->name = string_copy(ptr);
+	  while (*ptr++);
+	  h->address = string_copy(ptr);
+	  while(*ptr++);
+	  memcpy(&(h->port), ptr, sizeof(h->port));
+	  ptr += sizeof(h->port);
+	  h->dnssec = *ptr == '2' ? DS_YES
+		    : *ptr == '1' ? DS_NO
+		    : DS_UNK;
+	  ptr++;
+	  addr->host_used = h;
+	  }
+	else ptr++;
+
+	/* Finished with this address */
+
+	addr = addr->next;
+	break;
+      }
     break;
 
     /* Local interface address/port */
@@ -4423,7 +4438,6 @@ for (delivery_count = 0; addr_remote != NULL; delivery_count++)
 
       for (r = addr->retries; r != NULL; r = r->next)
         {
-        uschar *ptr;
         sprintf(CS big_buffer, "%c%.500s", r->flags, r->key);
         ptr = big_buffer + Ustrlen(big_buffer+2) + 3;
         memcpy(ptr, &(r->basic_errno), sizeof(r->basic_errno));
@@ -4438,11 +4452,31 @@ for (delivery_count = 0; addr_remote != NULL; delivery_count++)
         rmt_dlv_checked_write(fd, 'R', '0', big_buffer, ptr - big_buffer);
         }
 
-      /* The rest of the information goes in an 'A' item. */
+#ifdef EXPERIMENTAL_DSN_INFO
+/*um, are they really per-addr?  Other per-conn stuff is not (auth, tls).  But host_used is! */
+      if (addr->smtp_greeting)
+	{
+	ptr = big_buffer;
+	DEBUG(D_deliver) debug_printf("smtp_greeting '%s'\n", addr->smtp_greeting);
+        sprintf(CS ptr, "%.128s", addr->smtp_greeting);
+        while(*ptr++);
+	if (addr->helo_response)
+	  {
+	  DEBUG(D_deliver) debug_printf("helo_response '%s'\n", addr->helo_response);
+	  sprintf(CS ptr, "%.128s", addr->helo_response);
+	  while(*ptr++);
+	  }
+	else
+	  *ptr++ = '\0';
+        rmt_dlv_checked_write(fd, 'A', '1', big_buffer, ptr - big_buffer);
+	}
+#endif
+
+      /* The rest of the information goes in an 'A0' item. */
 
-      ptr = big_buffer + 2;
       sprintf(CS big_buffer, "%c%c", addr->transport_return,
         addr->special_action);
+      ptr = big_buffer + 2;
       memcpy(ptr, &(addr->basic_errno), sizeof(addr->basic_errno));
       ptr += sizeof(addr->basic_errno);
       memcpy(ptr, &(addr->more_errno), sizeof(addr->more_errno));
@@ -4480,7 +4514,11 @@ for (delivery_count = 0; addr_remote != NULL; delivery_count++)
       }
 
     /* Local interface address/port */
+#ifdef EXPERIMENTAL_DSN_INFO
+    if (sending_ip_address)
+#else
     if (LOGGING(incoming_interface) && sending_ip_address)
+#endif
       {
       uschar * ptr = big_buffer;
       sprintf(CS ptr, "%.128s", sending_ip_address);
@@ -7209,16 +7247,32 @@ wording. */
  
       for (addr = handled_addr; addr; addr = addr->next)
         {
+	host_item * hu;
         fprintf(f, "Action: failed\n"
 	    "Final-Recipient: rfc822;%s\n"
 	    "Status: 5.0.0\n",
 	    addr->address);
-        if (addr->host_used && addr->host_used->name)
-          {
-          fprintf(f, "Remote-MTA: dns; %s\n",
-	    addr->host_used->name);
-          print_dsn_diagnostic_code(addr, f);
-          }
+        if ((hu = addr->host_used) && hu->name)
+	  {
+	  const uschar * s;
+	  fprintf(f, "Remote-MTA: dns; %s\n",
+	    hu->name);
+#ifdef EXPERIMENTAL_DSN_INFO
+	  if (hu->address)
+	    {
+	    uschar * p = hu->port == 25
+	      ? US"" : string_sprintf(":%d", hu->port);
+	    fprintf(f, "Remote-MTA: X-ip; [%s]%s\n", hu->address, p);
+	    }
+	  if ((s = addr->smtp_greeting) && *s)
+	    fprintf(f, "X-Remote-MTA-smtp-greeting: X-str; %s\n", s);
+	  if ((s = addr->helo_response) && *s)
+	    fprintf(f, "X-Remote-MTA-helo-response: X-str; %s\n", s);
+	  if ((s = addr->message) && *s)
+	    fprintf(f, "X-Exim-Diagnostic: X-str; %s\n", s);
+#endif
+	  print_dsn_diagnostic_code(addr, f);
+	  }
 	fputc('\n', f);
         }
 
diff --git a/src/src/exim.c b/src/src/exim.c
index 999b94cc1..084d64990 100644
--- a/src/src/exim.c
+++ b/src/src/exim.c
@@ -847,6 +847,12 @@ fprintf(f, "Support for:");
 #ifdef EXPERIMENTAL_DMARC
   fprintf(f, " Experimental_DMARC");
 #endif
+#ifdef EXPERIMENTAL_DSN_INFO
+  fprintf(f, " Experimental_DSN_info");
+#endif
+#ifdef EXPERIMENTAL_INTERNATIONAL
+  fprintf(f, " Experimental_International");
+#endif
 #ifdef EXPERIMENTAL_PROXY
   fprintf(f, " Experimental_Proxy");
 #endif
@@ -859,9 +865,6 @@ fprintf(f, "Support for:");
 #ifdef EXPERIMENTAL_SOCKS
   fprintf(f, " Experimental_SOCKS");
 #endif
-#ifdef EXPERIMENTAL_INTERNATIONAL
-  fprintf(f, " Experimental_International");
-#endif
 fprintf(f, "\n");
 
 fprintf(f, "Lookups (built-in):");
diff --git a/src/src/globals.c b/src/src/globals.c
index 8445f001c..f3b6791f3 100644
--- a/src/src/globals.c
+++ b/src/src/globals.c
@@ -354,13 +354,17 @@ address_item address_defaults = {
   NULL,                 /* return_filename */
   NULL,                 /* self_hostname */
   NULL,                 /* shadow_message */
-  #ifdef SUPPORT_TLS
+#ifdef SUPPORT_TLS
   NULL,                 /* cipher */
   NULL,			/* ourcert */
   NULL,			/* peercert */
   NULL,                 /* peerdn */
   OCSP_NOT_REQ,         /* ocsp */
-  #endif
+#endif
+#ifdef EXPERIMENTAL_DSN_INFO
+  NULL,			/* smtp_greeting */
+  NULL,			/* helo_response */
+#endif
   NULL,			/* authenticator */
   NULL,			/* auth_id */
   NULL,			/* auth_sndr */
diff --git a/src/src/structs.h b/src/src/structs.h
index 438b52168..db9e843ac 100644
--- a/src/src/structs.h
+++ b/src/src/structs.h
@@ -561,13 +561,18 @@ typedef struct address_item {
   uschar *self_hostname;          /* after self=pass */
   uschar *shadow_message;         /* info about shadow transporting */
 
-  #ifdef SUPPORT_TLS
+#ifdef SUPPORT_TLS
   uschar *cipher;                 /* Cipher used for transport */
   void   *ourcert;                /* Certificate offered to peer, binary */
   void   *peercert;               /* Certificate from peer, binary */
   uschar *peerdn;                 /* DN of server's certificate */
   int    ocsp;			  /* OCSP status of peer cert */
-  #endif
+#endif
+
+#ifdef EXPERIMENTAL_DSN_INFO
+  const uschar *smtp_greeting;	  /* peer self-identification */
+  const uschar *helo_response;	  /* peer message */
+#endif
 
   uschar *authenticator;	  /* auth driver name used by transport */
   uschar *auth_id;		  /* auth "login" name used by transport */
diff --git a/src/src/transports/smtp.c b/src/src/transports/smtp.c
index c93f2ef8f..ac40460f1 100644
--- a/src/src/transports/smtp.c
+++ b/src/src/transports/smtp.c
@@ -440,6 +440,8 @@ Arguments:
   rc             to put in each address's transport_return field
   pass_message   if TRUE, set the "pass message" flag in the address
   host           if set, mark addrs as having used this host
+  smtp_greeting  from peer
+  helo_response  from peer
 
 If errno_value has the special value ERRNO_CONNECTTIMEOUT, ETIMEDOUT is put in
 the errno field, and RTEF_CTOUT is ORed into the more_errno field, to indicate
@@ -450,7 +452,11 @@ Returns:       nothing
 
 static void
 set_errno(address_item *addrlist, int errno_value, uschar *msg, int rc,
-  BOOL pass_message, host_item * host)
+  BOOL pass_message, host_item * host
+#ifdef EXPERIMENTAL_DSN_INFO
+  , const uschar * smtp_greeting, const uschar * helo_response
+#endif
+  )
 {
 address_item *addr;
 int orvalue = 0;
@@ -459,7 +465,7 @@ if (errno_value == ERRNO_CONNECTTIMEOUT)
   errno_value = ETIMEDOUT;
   orvalue = RTEF_CTOUT;
   }
-for (addr = addrlist; addr != NULL; addr = addr->next)
+for (addr = addrlist; addr; addr = addr->next)
   if (addr->transport_return >= PENDING)
     {
     addr->basic_errno = errno_value;
@@ -471,10 +477,31 @@ for (addr = addrlist; addr != NULL; addr = addr->next)
       }
     addr->transport_return = rc;
     if (host)
+      {
       addr->host_used = host;
+#ifdef EXPERIMENTAL_DSN_INFO
+      if (smtp_greeting)
+	{uschar * s = Ustrchr(smtp_greeting, '\n'); if (s) *s = '\0';}
+      addr->smtp_greeting = smtp_greeting;
+
+      if (helo_response)
+	{uschar * s = Ustrchr(helo_response, '\n'); if (s) *s = '\0';}
+      addr->helo_response = helo_response;
+#endif
+      }
     }
 }
 
+static void
+set_errno_nohost(address_item *addrlist, int errno_value, uschar *msg, int rc,
+  BOOL pass_message)
+{
+set_errno(addrlist, errno_value, msg, rc, pass_message, NULL
+#ifdef EXPERIMENTAL_DSN_INFO
+	  , NULL, NULL
+#endif
+	  );
+}
 
 
 /*************************************************
@@ -847,7 +874,7 @@ while (count-- > 0)
     {
     uschar *message = string_sprintf("SMTP timeout after RCPT TO:<%s>",
 			  transport_rcpt_address(addr, include_affixes));
-    set_errno(addrlist, ETIMEDOUT, message, DEFER, FALSE, NULL);
+    set_errno_nohost(addrlist, ETIMEDOUT, message, DEFER, FALSE);
     retry_add_item(addr, addr->address_retry_key, 0);
     update_waiting = FALSE;
     return -1;
@@ -1096,8 +1123,8 @@ if (is_esmtp && regex_match_and_setup(regex_AUTH, buffer, 0, -1))
 	  /* Internal problem, message in buffer. */
 
 	  case ERROR:
-	  set_errno(addrlist, ERRNO_AUTHPROB, string_copy(buffer),
-		    DEFER, FALSE, NULL);
+	  set_errno_nohost(addrlist, ERRNO_AUTHPROB, string_copy(buffer),
+		    DEFER, FALSE);
 	  return ERROR;
 	  }
 
@@ -1111,9 +1138,9 @@ if (is_esmtp && regex_match_and_setup(regex_AUTH, buffer, 0, -1))
 
 if (require_auth == OK && !smtp_authenticated)
   {
-  set_errno(addrlist, ERRNO_AUTHFAIL,
+  set_errno_nohost(addrlist, ERRNO_AUTHFAIL,
     string_sprintf("authentication required but %s", fail_reason), DEFER,
-    FALSE, NULL);
+    FALSE);
   return DEFER;
   }
 
@@ -1152,7 +1179,7 @@ if (ob->authenticated_sender != NULL)
       {
       uschar *message = string_sprintf("failed to expand "
         "authenticated_sender: %s", expand_string_message);
-      set_errno(addrlist, ERRNO_EXPANDFAIL, message, DEFER, FALSE, NULL);
+      set_errno_nohost(addrlist, ERRNO_EXPANDFAIL, message, DEFER, FALSE);
       return TRUE;
       }
     }
@@ -1381,6 +1408,10 @@ smtp_outblock outblock;
 int max_rcpt = tblock->max_addresses;
 uschar *igquotstr = US"";
 
+#ifdef EXPERIMENTAL_DSN_INFO
+uschar *smtp_greeting = NULL;
+uschar *helo_response = NULL;
+#endif
 uschar *helo_data = NULL;
 
 uschar *message = NULL;
@@ -1432,8 +1463,8 @@ tls_modify_variables(&tls_out);
 #ifndef SUPPORT_TLS
 if (smtps)
   {
-  set_errno(addrlist, ERRNO_TLSFAILURE, US"TLS support not available",
-	    DEFER, FALSE, NULL);
+  set_errno_nohost(addrlist, ERRNO_TLSFAILURE, US"TLS support not available",
+	    DEFER, FALSE);
   return ERROR;
   }
 #endif
@@ -1450,8 +1481,8 @@ if (continue_hostname == NULL)
 
   if (inblock.sock < 0)
     {
-    set_errno(addrlist, (errno == ETIMEDOUT)? ERRNO_CONNECTTIMEOUT : errno,
-      NULL, DEFER, FALSE, NULL);
+    set_errno_nohost(addrlist, (errno == ETIMEDOUT)? ERRNO_CONNECTTIMEOUT : errno,
+      NULL, DEFER, FALSE);
     return DEFER;
     }
 
@@ -1469,18 +1500,18 @@ if (continue_hostname == NULL)
 	&& dane_required	/* do not error on only dane-requested */
 	)
 	{
-	set_errno(addrlist, ERRNO_DNSDEFER,
+	set_errno_nohost(addrlist, ERRNO_DNSDEFER,
 	  string_sprintf("DANE error: tlsa lookup %s",
 	    rc == DEFER ? "DEFER" : "FAIL"),
-	  rc, FALSE, NULL);
+	  rc, FALSE);
 	return rc;
 	}
       }
     else if (dane_required)
       {
-      set_errno(addrlist, ERRNO_DNSDEFER,
+      set_errno_nohost(addrlist, ERRNO_DNSDEFER,
 	string_sprintf("DANE error: %s lookup not DNSSEC", host->name),
-	FAIL, FALSE, NULL);
+	FAIL, FALSE);
       return  FAIL;
       }
 
@@ -1501,7 +1532,7 @@ if (continue_hostname == NULL)
     if ((helo_data = string_domain_utf8_to_alabel(helo_data, &errstr)), errstr)
       {
       errstr = string_sprintf("failed to expand helo_data: %s", errstr);
-      set_errno(addrlist, ERRNO_EXPANDFAIL, errstr, DEFER, FALSE, NULL);
+      set_errno_nohost(addrlist, ERRNO_EXPANDFAIL, errstr, DEFER, FALSE);
       yield = DEFER;
       goto SEND_QUIT;
       }
@@ -1514,8 +1545,12 @@ if (continue_hostname == NULL)
 
   if (!smtps)
     {
-    if (!smtp_read_response(&inblock, buffer, sizeof(buffer), '2',
-      ob->command_timeout)) goto RESPONSE_FAILED;
+    BOOL good_response = smtp_read_response(&inblock, buffer, sizeof(buffer),
+      '2', ob->command_timeout);
+#ifdef EXPERIMENTAL_DSN_INFO
+    smtp_greeting = string_copy(buffer);
+#endif
+    if (!good_response) goto RESPONSE_FAILED;
 
 #ifdef EXPERIMENTAL_EVENT
       {
@@ -1525,9 +1560,9 @@ if (continue_hostname == NULL)
       s = event_raise(tblock->event_action, US"smtp:connect", buffer);
       if (s)
 	{
-	set_errno(addrlist, ERRNO_EXPANDFAIL,
+	set_errno_nohost(addrlist, ERRNO_EXPANDFAIL,
 	  string_sprintf("deferred by smtp:connect event expansion: %s", s),
-	  DEFER, FALSE, NULL);
+	  DEFER, FALSE);
 	yield = DEFER;
 	goto SEND_QUIT;
 	}
@@ -1541,7 +1576,7 @@ if (continue_hostname == NULL)
       {
       uschar *message = string_sprintf("failed to expand helo_data: %s",
         expand_string_message);
-      set_errno(addrlist, ERRNO_EXPANDFAIL, message, DEFER, FALSE, NULL);
+      set_errno_nohost(addrlist, ERRNO_EXPANDFAIL, message, DEFER, FALSE);
       yield = DEFER;
       goto SEND_QUIT;
       }
@@ -1606,9 +1641,18 @@ goto SEND_QUIT;
     if (!smtp_read_response(&inblock, buffer, sizeof(buffer), '2',
            ob->command_timeout))
       {
-      if (errno != 0 || buffer[0] == 0 || lmtp) goto RESPONSE_FAILED;
+      if (errno != 0 || buffer[0] == 0 || lmtp)
+	{
+#ifdef EXPERIMENTAL_DSN_INFO
+	helo_response = string_copy(buffer);
+#endif
+	goto RESPONSE_FAILED;
+	}
       esmtp = FALSE;
       }
+#ifdef EXPERIMENTAL_DSN_INFO
+    helo_response = string_copy(buffer);
+#endif
     }
   else
     {
@@ -1618,10 +1662,16 @@ goto SEND_QUIT;
 
   if (!esmtp)
     {
+    BOOL good_response;
+
     if (smtp_write_command(&outblock, FALSE, "HELO %s\r\n", helo_data) < 0)
       goto SEND_FAILED;
-    if (!smtp_read_response(&inblock, buffer, sizeof(buffer), '2',
-      ob->command_timeout)) goto RESPONSE_FAILED;
+    good_response = smtp_read_response(&inblock, buffer, sizeof(buffer),
+      '2', ob->command_timeout);
+#ifdef EXPERIMENTAL_DSN_INFO
+    helo_response = string_copy(buffer);
+#endif
+    if (!good_response) goto RESPONSE_FAILED;
     }
 
   /* Set IGNOREQUOTA if the response to LHLO specifies support and the
@@ -1671,6 +1721,11 @@ error messages. Note that smtp_use_size and smtp_use_pipelining will have been
 set from the command line if they were set in the process that passed the
 connection on. */
 
+/*XXX continue case needs to propagate DSN_INFO, prob. in deliver.c
+as the contine goes via transport_pass_socket() and doublefork and exec.
+It does not wait.  Unclear how we keep separate host's responses
+separate - we could match up by host ip+port as a bodge. */
+
 else
   {
   inblock.sock = outblock.sock = fileno(stdin);
@@ -1749,7 +1804,7 @@ if (  tls_offered
 
     /* TLS session is set up */
 
-    for (addr = addrlist; addr != NULL; addr = addr->next)
+    for (addr = addrlist; addr; addr = addr->next)
       if (addr->transport_return == PENDING_DEFER)
         {
         addr->cipher = tls_out.cipher;
@@ -1774,6 +1829,8 @@ start of the Exim process (in exim.c). */
 if (tls_out.active >= 0)
   {
   char *greeting_cmd;
+  BOOL good_response;
+
   if (helo_data == NULL)
     {
     helo_data = expand_string(ob->helo_data);
@@ -1781,7 +1838,7 @@ if (tls_out.active >= 0)
       {
       uschar *message = string_sprintf("failed to expand helo_data: %s",
         expand_string_message);
-      set_errno(addrlist, ERRNO_EXPANDFAIL, message, DEFER, FALSE, NULL);
+      set_errno_nohost(addrlist, ERRNO_EXPANDFAIL, message, DEFER, FALSE);
       yield = DEFER;
       goto SEND_QUIT;
       }
@@ -1790,8 +1847,12 @@ if (tls_out.active >= 0)
   /* For SMTPS we need to wait for the initial OK response. */
   if (smtps)
     {
-    if (!smtp_read_response(&inblock, buffer, sizeof(buffer), '2',
-      ob->command_timeout)) goto RESPONSE_FAILED;
+    good_response = smtp_read_response(&inblock, buffer, sizeof(buffer),
+      '2', ob->command_timeout);
+#ifdef EXPERIMENTAL_DSN_INFO
+    smtp_greeting = string_copy(buffer);
+#endif
+    if (!good_response) goto RESPONSE_FAILED;
     }
 
   if (esmtp)
@@ -1806,9 +1867,12 @@ if (tls_out.active >= 0)
   if (smtp_write_command(&outblock, FALSE, "%s %s\r\n",
         lmtp? "LHLO" : greeting_cmd, helo_data) < 0)
     goto SEND_FAILED;
-  if (!smtp_read_response(&inblock, buffer, sizeof(buffer), '2',
-       ob->command_timeout))
-    goto RESPONSE_FAILED;
+  good_response = smtp_read_response(&inblock, buffer, sizeof(buffer),
+    '2', ob->command_timeout);
+#ifdef EXPERIMENTAL_DSN_INFO
+  helo_response = string_copy(buffer);
+#endif
+  if (!good_response) goto RESPONSE_FAILED;
   }
 
 /* If the host is required to use a secure channel, ensure that we
@@ -1935,8 +1999,8 @@ if (tblock->filter_command != NULL)
 
   if (!rc)
     {
-    set_errno(addrlist->next, addrlist->basic_errno, addrlist->message, DEFER,
-      FALSE, NULL);
+    set_errno_nohost(addrlist->next, addrlist->basic_errno, addrlist->message, DEFER,
+      FALSE);
     yield = ERROR;
     goto SEND_QUIT;
     }
@@ -2065,7 +2129,7 @@ pending_MAIL = TRUE;     /* The block starts with MAIL */
     {
     if (s = string_address_utf8_to_alabel(return_path, &errstr), errstr)
       {
-      set_errno(addrlist, ERRNO_EXPANDFAIL, errstr, DEFER, FALSE, NULL);
+      set_errno_nohost(addrlist, ERRNO_EXPANDFAIL, errstr, DEFER, FALSE);
       yield = ERROR;
       goto SEND_QUIT;
       }
@@ -2217,8 +2281,8 @@ if (mua_wrapper)
     if (badaddr->transport_return != PENDING_OK)
       {
       /*XXX could we find a better errno than 0 here? */
-      set_errno(addrlist, 0, badaddr->message, FAIL,
-	testflag(badaddr, af_pass_message), NULL);
+      set_errno_nohost(addrlist, 0, badaddr->message, FAIL,
+	testflag(badaddr, af_pass_message));
       ok = FALSE;
       break;
       }
@@ -2475,7 +2539,7 @@ if (!ok) ok = TRUE; else
         else
           sprintf(CS buffer, "%.500s\n", addr->unique);
 
-        DEBUG(D_deliver) debug_printf("journalling %s", buffer);
+        DEBUG(D_deliver) debug_printf("journalling %s\n", buffer);
         len = Ustrlen(CS buffer);
         if (write(journal_fd, buffer, len) != len)
           log_write(0, LOG_MAIN|LOG_PANIC, "failed to write journal for "
@@ -2512,7 +2576,7 @@ if (!ok) ok = TRUE; else
           else
             sprintf(CS buffer, "%.500s\n", addr->unique);
 
-          DEBUG(D_deliver) debug_printf("journalling(PRDR) %s", buffer);
+          DEBUG(D_deliver) debug_printf("journalling(PRDR) %s\n", buffer);
           len = Ustrlen(CS buffer);
           if (write(journal_fd, buffer, len) != len)
             log_write(0, LOG_MAIN|LOG_PANIC, "failed to write journal for "
@@ -2542,22 +2606,27 @@ the problem is not related to this specific message. */
 
 if (!ok)
   {
-  int code;
+  int code, set_rc;
+  uschar * set_message;
 
   RESPONSE_FAILED:
-  save_errno = errno;
-  message = NULL;
-  send_quit = check_response(host, &save_errno, addrlist->more_errno,
-    buffer, &code, &message, &pass_message);
-  goto FAILED;
+    {
+    save_errno = errno;
+    message = NULL;
+    send_quit = check_response(host, &save_errno, addrlist->more_errno,
+      buffer, &code, &message, &pass_message);
+    goto FAILED;
+    }
 
   SEND_FAILED:
-  save_errno = errno;
-  code = '4';
-  message = US string_sprintf("send() to %s [%s] failed: %s",
-    host->name, host->address, strerror(save_errno));
-  send_quit = FALSE;
-  goto FAILED;
+    {
+    save_errno = errno;
+    code = '4';
+    message = US string_sprintf("send() to %s [%s] failed: %s",
+      host->name, host->address, strerror(save_errno));
+    send_quit = FALSE;
+    goto FAILED;
+    }
 
   /* This label is jumped to directly when a TLS negotiation has failed,
   or was not done for a host for which it is required. Values will be set
@@ -2578,16 +2647,14 @@ if (!ok)
 
   FAILED:
   ok = FALSE;                /* For when reached by GOTO */
+  set_message = message;
 
   if (setting_up)
     {
     if (code == '5')
-      set_errno(addrlist, save_errno, message, FAIL, pass_message, host);
+      set_rc = FAIL;
     else
-      {
-      set_errno(addrlist, save_errno, message, DEFER, pass_message, host);
-      yield = DEFER;
-      }
+      yield = set_rc = DEFER;
     }
 
   /* We want to handle timeouts after MAIL or "." and loss of connection after
@@ -2646,14 +2713,15 @@ if (!ok)
     if (message_error)
       {
       if (mua_wrapper) code = '5';  /* Force hard failure in wrapper mode */
-      set_errno(addrlist, save_errno, message, (code == '5')? FAIL : DEFER,
-        pass_message, host);
 
       /* If there's an errno, the message contains just the identity of
       the host. */
 
-      if (code != '5')     /* Anything other than 5 is treated as temporary */
+      if (code == '5')
+	set_rc = FAIL;
+      else		/* Anything other than 5 is treated as temporary */
         {
+	set_rc = DEFER;
         if (save_errno > 0)
           message = US string_sprintf("%s: %s", message, strerror(save_errno));
         if (host->next != NULL) log_write(0, LOG_MAIN, "%s", message);
@@ -2670,11 +2738,17 @@ if (!ok)
 
     else
       {
+      set_rc = DEFER;
       yield = (save_errno == ERRNO_CHHEADER_FAIL ||
                save_errno == ERRNO_FILTER_FAIL)? ERROR : DEFER;
-      set_errno(addrlist, save_errno, message, DEFER, pass_message, host);
       }
     }
+
+  set_errno(addrlist, save_errno, set_message, set_rc, pass_message, host
+#ifdef EXPERIMENTAL_DSN_INFO
+	    , smtp_greeting, helo_response
+#endif
+	    );
   }
 
 
@@ -2787,6 +2861,9 @@ if (completed_address && ok && send_quit)
       /* If the socket is successfully passed, we musn't send QUIT (or
       indeed anything!) from here. */
 
+/*XXX DSN_INFO: assume likely to do new HELO; but for greet we'll want to
+propagate it from the initial
+*/
       if (ok && transport_pass_socket(tblock->name, host->name, host->address,
             new_message_id, inblock.sock))
         {
@@ -2796,7 +2873,11 @@ if (completed_address && ok && send_quit)
 
     /* If RSET failed and there are addresses left, they get deferred. */
 
-    else set_errno(first_addr, errno, msg, DEFER, FALSE, host);
+    else set_errno(first_addr, errno, msg, DEFER, FALSE, host
+#ifdef EXPERIMENTAL_DSN_INFO
+		  , smtp_greeting, helo_response
+#endif
+		  );
     }
   }
 
@@ -2938,6 +3019,10 @@ for (addr = addrlist; addr != NULL; addr = addr->next)
     addr->peerdn = NULL;
     addr->ocsp = OCSP_NOT_REQ;
 #endif
+#ifdef EXPERIMENTAL_DSN_INFO
+    addr->smtp_greeting = NULL;
+    addr->helo_response = NULL;
+#endif
     }
 return first_addr;
 }
@@ -3479,7 +3564,7 @@ for (cutoff_retry = 0; expired &&
     if (dont_deliver)
       {
       host_item *host2;
-      set_errno(addrlist, 0, NULL, OK, FALSE, NULL);
+      set_errno_nohost(addrlist, 0, NULL, OK, FALSE);
       for (addr = addrlist; addr != NULL; addr = addr->next)
         {
         addr->host_used = host;
diff --git a/test/confs/4700 b/test/confs/4700
new file mode 120000
index 000000000..bf798671f
--- /dev/null
+++ b/test/confs/4700
@@ -0,0 +1 @@
+0211
\ No newline at end of file
diff --git a/test/log/4700 b/test/log/4700
new file mode 100644
index 000000000..35da72e04
--- /dev/null
+++ b/test/log/4700
@@ -0,0 +1,21 @@
+1999-03-02 09:44:33 10HmaX-0005vi-00 <= CALLER@test.ex U=CALLER P=local S=sss
+1999-03-02 09:44:33 10HmaX-0005vi-00 H=localhost4.test.ex [127.0.0.1]: SMTP error from remote mail server after initial connection: 450 I'm busy
+1999-03-02 09:44:33 10HmaX-0005vi-00 == userx@domain1 R=others T=smtp defer (0) H=localhost4.test.ex [127.0.0.1]: SMTP error from remote mail server after initial connection: 450 I'm busy
+1999-03-02 09:44:33 Start queue run: pid=pppp -qf
+1999-03-02 09:44:33 10HmaX-0005vi-00 H=localhost4.test.ex [127.0.0.1]: SMTP error from remote mail server after HELO the.local.host.name: 450 I'm busy
+1999-03-02 09:44:33 10HmaX-0005vi-00 == userx@domain1 R=others T=smtp defer (0) H=localhost4.test.ex [127.0.0.1]: SMTP error from remote mail server after HELO the.local.host.name: 450 I'm busy
+1999-03-02 09:44:33 End queue run: pid=pppp -qf
+1999-03-02 09:44:33 Start queue run: pid=pppp -qf
+1999-03-02 09:44:33 10HmaX-0005vi-00 ** userx@domain1 F=<CALLER@test.ex> R=others T=smtp H=localhost4.test.ex [127.0.0.1]: SMTP error from remote mail server after initial connection: 550 Go away
+1999-03-02 09:44:33 10HmaY-0005vi-00 <= <> R=10HmaX-0005vi-00 U=EXIMUSER P=local S=sss
+1999-03-02 09:44:33 10HmaY-0005vi-00 => CALLER <CALLER@test.ex> F=<> R=all T=local_delivery
+1999-03-02 09:44:33 10HmaY-0005vi-00 Completed
+1999-03-02 09:44:33 10HmaX-0005vi-00 Completed
+1999-03-02 09:44:33 End queue run: pid=pppp -qf
+1999-03-02 09:44:33 10HmaZ-0005vi-00 <= CALLER@test.ex U=CALLER P=local S=sss
+1999-03-02 09:44:33 10HmaZ-0005vi-00 ** userx@domain1 F=<CALLER@test.ex> R=others T=smtp H=localhost4.test.ex [127.0.0.1]: SMTP error from remote mail server after HELO the.local.host.name: 550 Go away
+1999-03-02 09:44:33 10HmaZ-0005vi-00 ** usery@domain2 F=<CALLER@test.ex> R=others T=smtp H=localhost4.test.ex [127.0.0.1]: SMTP error from remote mail server after HELO the.local.host.name: 550 Go away
+1999-03-02 09:44:33 10HmbA-0005vi-00 <= <> R=10HmaZ-0005vi-00 U=EXIMUSER P=local S=sss
+1999-03-02 09:44:33 10HmbA-0005vi-00 => CALLER <CALLER@test.ex> F=<> R=all T=local_delivery
+1999-03-02 09:44:33 10HmbA-0005vi-00 Completed
+1999-03-02 09:44:33 10HmaZ-0005vi-00 Completed
diff --git a/test/mail/4700.CALLER b/test/mail/4700.CALLER
new file mode 100644
index 000000000..bde98db7d
--- /dev/null
+++ b/test/mail/4700.CALLER
@@ -0,0 +1,131 @@
+From MAILER-DAEMON Tue Mar 02 09:44:33 1999
+Return-path: <>
+Received: from EXIMUSER by the.local.host.name with local (Exim x.yz)
+	id 10HmaY-0005vi-00
+	for CALLER@test.ex; Tue, 2 Mar 1999 09:44:33 +0000
+X-Failed-Recipients: userx@domain1
+Auto-Submitted: auto-replied
+From: Mail Delivery System <Mailer-Daemon@test.ex>
+To: CALLER@test.ex
+Content-Type: multipart/report; report-type=delivery-status; boundary=NNNNNNNNNN-eximdsn-MMMMMMMMMM
+MIME-Version: 1.0
+Subject: Mail delivery failed: returning message to sender
+Message-Id: <E10HmaY-0005vi-00@the.local.host.name>
+Date: Tue, 2 Mar 1999 09:44:33 +0000
+
+--NNNNNNNNNN-eximdsn-MMMMMMMMMM
+Content-type: text/plain; charset=us-ascii
+
+This message was created automatically by mail delivery software.
+
+A message that you sent could not be delivered to one or more of its
+recipients. This is a permanent error. The following address(es) failed:
+
+  userx@domain1
+  host localhost4.test.ex [127.0.0.1]
+    SMTP error from remote mail server after initial connection:
+    550 Go away
+
+--NNNNNNNNNN-eximdsn-MMMMMMMMMM
+Content-type: message/delivery-status
+
+Reporting-MTA: dns; the.local.host.name
+
+Action: failed
+Final-Recipient: rfc822;userx@domain1
+Status: 5.0.0
+Remote-MTA: dns; localhost4.test.ex
+Remote-MTA: X-ip; [127.0.0.1]:1111
+X-Remote-MTA-smtp-greeting: X-str; 550 Go away
+X-Exim-Diagnostic: X-str; SMTP error from remote mail server after initial connection: 550 Go away
+Diagnostic-Code: smtp; 550 Go away
+
+--NNNNNNNNNN-eximdsn-MMMMMMMMMM
+Content-type: message/rfc822
+
+Return-path: <CALLER@test.ex>
+Received: from CALLER by the.local.host.name with local (Exim x.yz)
+	(envelope-from <CALLER@test.ex>)
+	id 10HmaX-0005vi-00
+	for userx@domain1; Tue, 2 Mar 1999 09:44:33 +0000
+Message-Id: <E10HmaX-0005vi-00@the.local.host.name>
+From: CALLER_NAME <CALLER@test.ex>
+Date: Tue, 2 Mar 1999 09:44:33 +0000
+
+Test message 1
+
+--NNNNNNNNNN-eximdsn-MMMMMMMMMM--
+
+From MAILER-DAEMON Tue Mar 02 09:44:33 1999
+Return-path: <>
+Received: from EXIMUSER by the.local.host.name with local (Exim x.yz)
+	id 10HmbA-0005vi-00
+	for CALLER@test.ex; Tue, 2 Mar 1999 09:44:33 +0000
+X-Failed-Recipients: usery@domain2,
+  userx@domain1
+Auto-Submitted: auto-replied
+From: Mail Delivery System <Mailer-Daemon@test.ex>
+To: CALLER@test.ex
+Content-Type: multipart/report; report-type=delivery-status; boundary=NNNNNNNNNN-eximdsn-MMMMMMMMMM
+MIME-Version: 1.0
+Subject: Mail delivery failed: returning message to sender
+Message-Id: <E10HmbA-0005vi-00@the.local.host.name>
+Date: Tue, 2 Mar 1999 09:44:33 +0000
+
+--NNNNNNNNNN-eximdsn-MMMMMMMMMM
+Content-type: text/plain; charset=us-ascii
+
+This message was created automatically by mail delivery software.
+
+A message that you sent could not be delivered to one or more of its
+recipients. This is a permanent error. The following address(es) failed:
+
+  usery@domain2
+  host localhost4.test.ex [127.0.0.1]
+    SMTP error from remote mail server after HELO the.local.host.name:
+    550 Go away
+  userx@domain1
+  host localhost4.test.ex [127.0.0.1]
+    SMTP error from remote mail server after HELO the.local.host.name:
+    550 Go away
+
+--NNNNNNNNNN-eximdsn-MMMMMMMMMM
+Content-type: message/delivery-status
+
+Reporting-MTA: dns; the.local.host.name
+
+Action: failed
+Final-Recipient: rfc822;userx@domain1
+Status: 5.0.0
+Remote-MTA: dns; localhost4.test.ex
+Remote-MTA: X-ip; [127.0.0.1]:1111
+X-Remote-MTA-smtp-greeting: X-str; 220 Connected OK
+X-Remote-MTA-helo-response: X-str; 550 Go away
+X-Exim-Diagnostic: X-str; SMTP error from remote mail server after HELO the.local.host.name: 550 Go away
+Diagnostic-Code: smtp; 550 Go away
+
+Action: failed
+Final-Recipient: rfc822;usery@domain2
+Status: 5.0.0
+Remote-MTA: dns; localhost4.test.ex
+Remote-MTA: X-ip; [127.0.0.1]:1111
+X-Remote-MTA-smtp-greeting: X-str; 220 Connected OK
+X-Remote-MTA-helo-response: X-str; 550 Go away
+X-Exim-Diagnostic: X-str; SMTP error from remote mail server after HELO the.local.host.name: 550 Go away
+Diagnostic-Code: smtp; 550 Go away
+
+--NNNNNNNNNN-eximdsn-MMMMMMMMMM
+Content-type: message/rfc822
+
+Return-path: <CALLER@test.ex>
+Received: from CALLER by the.local.host.name with local (Exim x.yz)
+	(envelope-from <CALLER@test.ex>)
+	id 10HmaZ-0005vi-00; Tue, 2 Mar 1999 09:44:33 +0000
+Message-Id: <E10HmaZ-0005vi-00@the.local.host.name>
+From: CALLER_NAME <CALLER@test.ex>
+Date: Tue, 2 Mar 1999 09:44:33 +0000
+
+Test message 2
+
+--NNNNNNNNNN-eximdsn-MMMMMMMMMM--
+
diff --git a/test/scripts/4700-dsn-info/4700 b/test/scripts/4700-dsn-info/4700
new file mode 120000
index 000000000..e480f3494
--- /dev/null
+++ b/test/scripts/4700-dsn-info/4700
@@ -0,0 +1 @@
+../0000-Basic/0211
\ No newline at end of file
diff --git a/test/scripts/4700-dsn-info/REQUIRES b/test/scripts/4700-dsn-info/REQUIRES
new file mode 100644
index 000000000..683fc9019
--- /dev/null
+++ b/test/scripts/4700-dsn-info/REQUIRES
@@ -0,0 +1 @@
+support Experimental_DSN_info
diff --git a/test/stdout/4700 b/test/stdout/4700
new file mode 100644
index 000000000..446203b4f
--- /dev/null
+++ b/test/stdout/4700
@@ -0,0 +1,34 @@
+
+******** SERVER ********
+Listening on port 1224 ... 
+Connection request from [127.0.0.1]
+450 I'm busy
+QUIT
+250 OK
+End of script
+Listening on port 1224 ... 
+Connection request from [127.0.0.1]
+220 Connected OK
+EHLO the.local.host.name
+450 I'm busy
+HELO the.local.host.name
+450 I'm busy
+QUIT
+250 OK
+End of script
+Listening on port 1224 ... 
+Connection request from [127.0.0.1]
+550 Go away
+QUIT
+250 OK
+End of script
+Listening on port 1224 ... 
+Connection request from [127.0.0.1]
+220 Connected OK
+EHLO the.local.host.name
+550 Go away
+HELO the.local.host.name
+550 Go away
+QUIT
+250 OK
+End of script