DANE: Remove fallback from hosts_try_dane. If TLSA record not retrieved,

do not use this host.

diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index 496e9d07e245702571453dd2665ad670e3b599fe..cecd2a0388173049d9da37e23be9c3c5d632f832 100644 (file)
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -10,6 +10,16 @@ JH/02 The obsolete acl condition "demime" is removed (finally, after ten
       years of being deprecated). The replacements are the ACLs
       acl_smtp_mime and acl_not_smtp_mime.
 
+JH/03 Upgrade security requirements imposed for hosts_try_dane: previously
+      a downgraded non-dane trust-anchor for the TLS connection (CA-style)
+      or even an in-clear connection were permitted.  Now, if the host lookup
+      was dnssec and dane was requested then the host is only used if the
+      TLSA lookup succeeds and is dnssec.  Further hosts (eg. lower priority
+      MXs) will be tried (for hosts_try_dane though not for hosts_require_dane)
+      if one fails this test.
+      This means that a poorly-configured remote DNS will make it incommunicado;
+      but it protects against a DNS-interception attack on it.
+
 
 Exim version 4.87
 -----------------

diff --git a/doc/doc-txt/experimental-spec.txt b/doc/doc-txt/experimental-spec.txt
index 4836a7d514f1e7cf138a4b7bafc0e7266f54ea7f..993b5b05cfdd260d30608e045b565ada6c70fc2e 100644 (file)
--- a/doc/doc-txt/experimental-spec.txt
+++ b/doc/doc-txt/experimental-spec.txt
@@ -884,18 +884,20 @@ with DANE in their OCSP settings.
 
 
 For client-side DANE there are two new smtp transport options,
-hosts_try_dane and hosts_require_dane.  They do the obvious thing.
+hosts_try_dane and hosts_require_dane.
 [ should they be domain-based rather than host-based? ]
 
+Hosts_require_dane will result in failure if the target host
+is not DNSSEC-secured.
+
 DANE will only be usable if the target host has DNSSEC-secured
 MX, A and TLSA records.
 
 A TLSA lookup will be done if either of the above options match
 and the host-lookup succeded using dnssec.
 If a TLSA lookup is done and succeeds, a DANE-verified TLS connection
-will be required for the host.
-
-(TODO: specify when fallback happens vs. when the host is not used)
+will be required for the host.  If it does not, the host will not
+be used; there is no fallback to non-DANE or non-TLS.
 
 If DANE is requested and useable (see above) the following transport
 options are ignored:

diff --git a/src/src/dns.c b/src/src/dns.c
index 1d5384e9d6fa03aa90f64449e95dd37b5901a122..575b815605dba78d7a2f72193e04c1e3179d2f33 100644 (file)
--- a/src/src/dns.c
+++ b/src/src/dns.c
@@ -663,8 +663,7 @@ caching for successful lookups. */
 
 sprintf(CS node_name, "%.255s-%s-%lx", name, dns_text_type(type),
   (unsigned long) resp->options);
-previous = tree_search(tree_dns_fails, node_name);
-if (previous != NULL)
+if ((previous = tree_search(tree_dns_fails, node_name)))
   {
   DEBUG(D_dns) debug_printf("DNS lookup of %.255s-%s: using cached value %s\n",
     name, dns_text_type(type),
@@ -769,48 +768,48 @@ if (dnsa->answerlen > MAXPACKET)
 if (dnsa->answerlen < 0) switch (h_errno)
   {
   case HOST_NOT_FOUND:
-  DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave HOST_NOT_FOUND\n"
-    "returning DNS_NOMATCH\n", name, dns_text_type(type));
-  return dns_return(name, type, DNS_NOMATCH);
+    DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave HOST_NOT_FOUND\n"
+      "returning DNS_NOMATCH\n", name, dns_text_type(type));
+    return dns_return(name, type, DNS_NOMATCH);
 
   case TRY_AGAIN:
-  DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave TRY_AGAIN\n",
-    name, dns_text_type(type));
+    DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave TRY_AGAIN\n",
+      name, dns_text_type(type));
 
-  /* Cut this out for various test programs */
+    /* Cut this out for various test programs */
 #ifndef STAND_ALONE
-  save_domain = deliver_domain;
-  deliver_domain = string_copy(name);  /* set $domain */
-  rc = match_isinlist(name, (const uschar **)&dns_again_means_nonexist, 0, NULL, NULL,
-    MCL_DOMAIN, TRUE, NULL);
-  deliver_domain = save_domain;
-  if (rc != OK)
-    {
-    DEBUG(D_dns) debug_printf("returning DNS_AGAIN\n");
-    return dns_return(name, type, DNS_AGAIN);
-    }
-  DEBUG(D_dns) debug_printf("%s is in dns_again_means_nonexist: returning "
-    "DNS_NOMATCH\n", name);
-  return dns_return(name, type, DNS_NOMATCH);
+    save_domain = deliver_domain;
+    deliver_domain = string_copy(name);  /* set $domain */
+    rc = match_isinlist(name, (const uschar **)&dns_again_means_nonexist, 0, NULL, NULL,
+      MCL_DOMAIN, TRUE, NULL);
+    deliver_domain = save_domain;
+    if (rc != OK)
+      {
+      DEBUG(D_dns) debug_printf("returning DNS_AGAIN\n");
+      return dns_return(name, type, DNS_AGAIN);
+      }
+    DEBUG(D_dns) debug_printf("%s is in dns_again_means_nonexist: returning "
+      "DNS_NOMATCH\n", name);
+    return dns_return(name, type, DNS_NOMATCH);
 
 #else   /* For stand-alone tests */
-  return dns_return(name, type, DNS_AGAIN);
+    return dns_return(name, type, DNS_AGAIN);
 #endif
 
   case NO_RECOVERY:
-  DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave NO_RECOVERY\n"
-    "returning DNS_FAIL\n", name, dns_text_type(type));
-  return dns_return(name, type, DNS_FAIL);
+    DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave NO_RECOVERY\n"
+      "returning DNS_FAIL\n", name, dns_text_type(type));
+    return dns_return(name, type, DNS_FAIL);
 
   case NO_DATA:
-  DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave NO_DATA\n"
-    "returning DNS_NODATA\n", name, dns_text_type(type));
-  return dns_return(name, type, DNS_NODATA);
+    DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave NO_DATA\n"
+      "returning DNS_NODATA\n", name, dns_text_type(type));
+    return dns_return(name, type, DNS_NODATA);
 
   default:
-  DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave unknown DNS error %d\n"
-    "returning DNS_FAIL\n", name, dns_text_type(type), h_errno);
-  return dns_return(name, type, DNS_FAIL);
+    DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave unknown DNS error %d\n"
+      "returning DNS_FAIL\n", name, dns_text_type(type), h_errno);
+    return dns_return(name, type, DNS_FAIL);
   }
 
 DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) succeeded\n",

diff --git a/src/src/functions.h b/src/src/functions.h
index 4fbabcd81cf93669ac7398d4195e8c45384d3b8c..6c3c37463aba66d8f745ee8e02d3112484498cbf 100644 (file)
--- a/src/src/functions.h
+++ b/src/src/functions.h
@@ -71,7 +71,7 @@ extern uschar * tls_field_from_dn(uschar *, const uschar *);
 extern BOOL    tls_is_name_for_cert(const uschar *, void *);
 
 # ifdef EXPERIMENTAL_DANE
-extern int     tlsa_lookup(const host_item *, dns_answer *, BOOL, BOOL *);
+extern int     tlsa_lookup(const host_item *, dns_answer *, BOOL);
 # endif
 
 #endif /*SUPPORT_TLS*/

diff --git a/src/src/transports/smtp.c b/src/src/transports/smtp.c
index a8a78d94546211a70f2a4c4445bff31ca2747bb4..361531a9fee83c938d732b3e64c8b0ea4d35a18d 100644 (file)
--- a/src/src/transports/smtp.c
+++ b/src/src/transports/smtp.c
@@ -1216,8 +1216,7 @@ return FALSE;
 
 #ifdef EXPERIMENTAL_DANE
 int
-tlsa_lookup(const host_item * host, dns_answer * dnsa,
-  BOOL dane_required, BOOL * dane)
+tlsa_lookup(const host_item * host, dns_answer * dnsa, BOOL dane_required)
 {
 /* move this out to host.c given the similarity to dns_lookup() ? */
 uschar buffer[300];
@@ -1233,9 +1232,7 @@ switch (dns_lookup(dnsa, buffer, T_TLSA, &fullname))
 
   default:
   case DNS_FAIL:
-    if (dane_required)
-      return FAIL;
-    break;
+    return dane_required ? FAIL : DEFER;
 
   case DNS_SUCCEED:
     if (!dns_is_secure(dnsa))
@@ -1243,10 +1240,8 @@ switch (dns_lookup(dnsa, buffer, T_TLSA, &fullname))
       log_write(0, LOG_MAIN, "DANE error: TLSA lookup not DNSSEC");
       return DEFER;
       }
-    *dane = TRUE;
-    break;
+    return OK;
   }
-return OK;
 }
 #endif
 
@@ -1545,18 +1540,19 @@ if (continue_hostname == NULL)
 
     if (host->dnssec == DS_YES)
       {
-      if(  (  dane_required
-          || verify_check_given_host(&ob->hosts_try_dane, host) == OK
-          )
-       && (rc = tlsa_lookup(host, &tlsa_dnsa, dane_required, &dane)) != OK
-       && dane_required        /* do not error on only dane-requested */
+      if(  dane_required
+       || verify_check_given_host(&ob->hosts_try_dane, host) == OK
        )
        {
-       set_errno_nohost(addrlist, ERRNO_DNSDEFER,
-         string_sprintf("DANE error: tlsa lookup %s",
-           rc == DEFER ? "DEFER" : "FAIL"),
-         rc, FALSE);
-       return rc;
+       if ((rc = tlsa_lookup(host, &tlsa_dnsa, dane_required)) != OK)
+         {
+         set_errno_nohost(addrlist, ERRNO_DNSDEFER,
+           string_sprintf("DANE error: tlsa lookup %s",
+             rc == DEFER ? "DEFER" : "FAIL"),
+           rc, FALSE);
+         return rc;
+         }
+       dane = TRUE;
        }
       }
     else if (dane_required)
@@ -1564,7 +1560,7 @@ if (continue_hostname == NULL)
       set_errno_nohost(addrlist, ERRNO_DNSDEFER,
        string_sprintf("DANE error: %s lookup not DNSSEC", host->name),
        FAIL, FALSE);
-      return  FAIL;
+      return FAIL;
       }
 
     if (dane)
@@ -1790,8 +1786,10 @@ if (  tls_offered
   if (!smtp_read_response(&inblock, buffer2, sizeof(buffer2), '2',
       ob->command_timeout))
     {
-    if (errno != 0 || buffer2[0] == 0 ||
-         (buffer2[0] == '4' && !ob->tls_tempfail_tryclear))
+    if (  errno != 0
+       || buffer2[0] == 0
+       || (buffer2[0] == '4' && !ob->tls_tempfail_tryclear)
+       )
       {
       Ustrncpy(buffer, buffer2, sizeof(buffer));
       goto RESPONSE_FAILED;
@@ -1816,13 +1814,11 @@ if (  tls_offered
     if (rc != OK)
       {
 # ifdef EXPERIMENTAL_DANE
-      if (rc == DEFER && dane && !dane_required)
+      if (rc == DEFER && dane)
        {
-       log_write(0, LOG_MAIN, "DANE attempt failed;"
-         " trying CA-root TLS to %s [%s] (not in hosts_require_dane)",
+       log_write(0, LOG_MAIN,
+         "DANE attempt failed; no TLS connection to %s [%s]",
          host->name, host->address);
-       dane = FALSE;
-       goto TLS_NEGOTIATE;
        }
 # endif
 

diff --git a/src/src/verify.c b/src/src/verify.c
index f64057fd1fb6b657bf7440f3193d2fb38f508e2a..04c781e54030775bd29f5dae759cc7450b2bf9e1 100644 (file)
--- a/src/src/verify.c
+++ b/src/src/verify.c
@@ -640,12 +640,14 @@ can do it there for the non-rcpt-verify case.  For this we keep an addresscount.
 
       if (host->dnssec == DS_YES)
        {
-       if(  (  dane_required
-            || verify_check_given_host(&ob->hosts_try_dane, host) == OK
-            )
-         && (rc = tlsa_lookup(host, &tlsa_dnsa, dane_required, &dane)) != OK
+       if(  dane_required
+         || verify_check_given_host(&ob->hosts_try_dane, host) == OK
          )
-         return rc;
+         {
+         if ((rc = tlsa_lookup(host, &tlsa_dnsa, dane_required)) != OK)
+           return rc;
+         dane = TRUE;
+         }
        }
       else if (dane_required)
        {
@@ -792,8 +794,10 @@ can do it there for the non-rcpt-verify case.  For this we keep an addresscount.
       if (!smtps && !smtp_read_response(&inblock, buffer2, sizeof(buffer2), '2',
                        ob->command_timeout))
         {
-        if (errno != 0 || buffer2[0] == 0 ||
-               (buffer2[0] == '4' && !ob->tls_tempfail_tryclear))
+        if (  errno != 0
+          || buffer2[0] == 0
+          || buffer2[0] == '4' && !ob->tls_tempfail_tryclear
+          )
          {
          Ustrncpy(responsebuffer, buffer2, sizeof(responsebuffer));
          done= FALSE;
@@ -827,24 +831,10 @@ can do it there for the non-rcpt-verify case.  For this we keep an addresscount.
            (void) event_raise(addr->transport->event_action,
                                    US"tcp:close", NULL);
 # endif
-# ifdef EXPERIMENTAL_DANE
-           if (dane)
-             {
-             if (!dane_required)
-               {
-               log_write(0, LOG_MAIN, "DANE attempt failed;"
-                 " trying CA-root TLS to %s [%s] (not in hosts_require_dane)",
-                 host->name, host->address);
-               dane = FALSE;
-               goto tls_negotiate;
-               }
-             }
-           else
-# endif
-             if (  ob->tls_tempfail_tryclear
-                && !smtps
-                && verify_check_given_host(&ob->hosts_require_tls, host) != OK
-                )
+           if (  ob->tls_tempfail_tryclear
+              && !smtps
+              && verify_check_given_host(&ob->hosts_require_tls, host) != OK
+              )
              {
              log_write(0, LOG_MAIN, "TLS session failure:"
                " delivering unencrypted to %s [%s] (not in hosts_require_tls)",

diff --git a/test/confs/5840 b/test/confs/5840
index e83919005e28cf4100e2b31bd84bbfe92c3940ae..670ce2c196f5fbac80ddebcc84ae3a2a94f198c0 100644 (file)
--- a/test/confs/5840
+++ b/test/confs/5840
@@ -52,6 +52,7 @@ client:
   dnssec_request_domains = *
   self = send
   transport = send_to_server
+  errors_to = ""
 
 server:
   driver = redirect

diff --git a/test/log/5840 b/test/log/5840
index 7823a2ae928f64d6b3a71c1f625274d984727692..4e45703ca08b6c1b1fc62637132c929e2582d260 100644 (file)
--- a/test/log/5840
+++ b/test/log/5840
@@ -28,45 +28,33 @@
 1999-03-02 09:44:33 10HmbJ-0005vi-00 <= CALLER@myhost.test.ex U=CALLER P=local S=sss for CALLER@dane.no.2.test.ex
 1999-03-02 09:44:33 Start queue run: pid=pppp -qf
 1999-03-02 09:44:33 10HmbH-0005vi-00 H=danelazy.test.ex [ip4.ip4.ip4.ip4]: DANE error: tlsa lookup DEFER
-1999-03-02 09:44:33 10HmbH-0005vi-00 [127.0.0.1] SSL verify error: depth=0 error=self signed certificate cert=/C=UK/O=The Exim Maintainers/OU=Test Suite/CN=Phil Pennock
-1999-03-02 09:44:33 10HmbH-0005vi-00 [127.0.0.1] SSL verify error: certificate name mismatch: "/C=UK/O=The Exim Maintainers/OU=Test Suite/CN=Phil Pennock"
-1999-03-02 09:44:33 10HmbH-0005vi-00 => CALLER@mxdanelazy.test.ex R=client T=send_to_server H=danelazy2.test.ex [127.0.0.1] X=TLSv1:AES256-SHA:256 CV=no DN="/C=UK/O=The Exim Maintainers/OU=Test Suite/CN=Phil Pennock" C="250 OK id=10HmbK-0005vi-00"
-1999-03-02 09:44:33 10HmbH-0005vi-00 Completed
+1999-03-02 09:44:33 10HmbH-0005vi-00 H=danelazy2.test.ex [127.0.0.1]: DANE error: tlsa lookup DEFER
+1999-03-02 09:44:33 10HmbH-0005vi-00 == CALLER@mxdanelazy.test.ex R=client T=send_to_server defer (-36): DANE error: tlsa lookup DEFER
 1999-03-02 09:44:33 10HmbI-0005vi-00 ** CALLER@dane.no.1.test.ex R=client T=send_to_server: DANE error: tlsa lookup FAIL
-1999-03-02 09:44:33 10HmbL-0005vi-00 <= <> R=10HmbI-0005vi-00 U=EXIMUSER P=local S=sss for CALLER@myhost.test.ex
-1999-03-02 09:44:33 10HmbL-0005vi-00 H=myhost.test.ex [V4NET.10.10.10] Network Error
-1999-03-02 09:44:33 10HmbL-0005vi-00 == CALLER@myhost.test.ex R=client T=send_to_server defer (dd): Network Error
+1999-03-02 09:44:33 10HmbI-0005vi-00 CALLER@dane.no.1.test.ex: error ignored
 1999-03-02 09:44:33 10HmbI-0005vi-00 Completed
-1999-03-02 09:44:33 10HmbJ-0005vi-00 [127.0.0.1] SSL verify error: depth=0 error=self signed certificate cert=/C=UK/O=The Exim Maintainers/OU=Test Suite/CN=Phil Pennock
-1999-03-02 09:44:33 10HmbJ-0005vi-00 [127.0.0.1] SSL verify error: certificate name mismatch: "/C=UK/O=The Exim Maintainers/OU=Test Suite/CN=Phil Pennock"
-1999-03-02 09:44:33 10HmbJ-0005vi-00 => CALLER@dane.no.2.test.ex R=client T=send_to_server H=dane.no.2.test.ex [127.0.0.1] X=TLSv1:AES256-SHA:256 CV=no DN="/C=UK/O=The Exim Maintainers/OU=Test Suite/CN=Phil Pennock" C="250 OK id=10HmbM-0005vi-00"
-1999-03-02 09:44:33 10HmbJ-0005vi-00 Completed
+1999-03-02 09:44:33 10HmbJ-0005vi-00 H=dane.no.2.test.ex [127.0.0.1]: DANE error: tlsa lookup DEFER
+1999-03-02 09:44:33 10HmbJ-0005vi-00 == CALLER@dane.no.2.test.ex R=client T=send_to_server defer (-36): DANE error: tlsa lookup DEFER
 1999-03-02 09:44:33 End queue run: pid=pppp -qf
 
 ******** SERVER ********
 1999-03-02 09:44:33 exim x.yz daemon started: pid=pppp, no queue runs, listening for SMTP on port 1225
-1999-03-02 09:44:33 10HmaZ-0005vi-00 <= CALLER@myhost.test.ex H=the.local.host.name (myhost.test.ex) [ip4.ip4.ip4.ip4] P=esmtps X=TLSv1:AES256-SHA:256 CV=no S=sss id=E10HmaX-0005vi-00@myhost.test.ex for CALLER@dane256ee.test.ex
+1999-03-02 09:44:33 10HmaZ-0005vi-00 <= <> H=the.local.host.name (myhost.test.ex) [ip4.ip4.ip4.ip4] P=esmtps X=TLSv1:AES256-SHA:256 CV=no S=sss id=E10HmaX-0005vi-00@myhost.test.ex for CALLER@dane256ee.test.ex
 1999-03-02 09:44:33 10HmaZ-0005vi-00 => :blackhole: <CALLER@dane256ee.test.ex> R=server
 1999-03-02 09:44:33 10HmaZ-0005vi-00 Completed
-1999-03-02 09:44:33 10HmbA-0005vi-00 <= CALLER@myhost.test.ex H=the.local.host.name (myhost.test.ex) [ip4.ip4.ip4.ip4] P=esmtps X=TLSv1:AES256-SHA:256 CV=no S=sss id=E10HmaY-0005vi-00@myhost.test.ex for CALLER@mxdane512ee.test.ex
+1999-03-02 09:44:33 10HmbA-0005vi-00 <= <> H=the.local.host.name (myhost.test.ex) [ip4.ip4.ip4.ip4] P=esmtps X=TLSv1:AES256-SHA:256 CV=no S=sss id=E10HmaY-0005vi-00@myhost.test.ex for CALLER@mxdane512ee.test.ex
 1999-03-02 09:44:33 10HmbA-0005vi-00 => :blackhole: <CALLER@mxdane512ee.test.ex> R=server
 1999-03-02 09:44:33 10HmbA-0005vi-00 Completed
 1999-03-02 09:44:33 exim x.yz daemon started: pid=pppp, no queue runs, listening for SMTP on port 1225
-1999-03-02 09:44:33 10HmbC-0005vi-00 <= CALLER@myhost.test.ex H=the.local.host.name (myhost.test.ex) [ip4.ip4.ip4.ip4] P=esmtps X=TLSv1:AES256-SHA:256 CV=no S=sss id=E10HmbB-0005vi-00@myhost.test.ex for CALLER@mxdane256ta.test.ex
+1999-03-02 09:44:33 10HmbC-0005vi-00 <= <> H=the.local.host.name (myhost.test.ex) [ip4.ip4.ip4.ip4] P=esmtps X=TLSv1:AES256-SHA:256 CV=no S=sss id=E10HmbB-0005vi-00@myhost.test.ex for CALLER@mxdane256ta.test.ex
 1999-03-02 09:44:33 10HmbC-0005vi-00 => :blackhole: <CALLER@mxdane256ta.test.ex> R=server
 1999-03-02 09:44:33 10HmbC-0005vi-00 Completed
 1999-03-02 09:44:33 exim x.yz daemon started: pid=pppp, no queue runs, listening for SMTP on port 1225
-1999-03-02 09:44:33 10HmbE-0005vi-00 <= CALLER@myhost.test.ex H=localhost (myhost.test.ex) [127.0.0.1] P=esmtps X=TLSv1:AES256-SHA:256 CV=no S=sss id=E10HmbD-0005vi-00@myhost.test.ex for CALLER@thishost.test.ex
+1999-03-02 09:44:33 10HmbE-0005vi-00 <= <> H=localhost (myhost.test.ex) [127.0.0.1] P=esmtps X=TLSv1:AES256-SHA:256 CV=no S=sss id=E10HmbD-0005vi-00@myhost.test.ex for CALLER@thishost.test.ex
 1999-03-02 09:44:33 10HmbE-0005vi-00 => :blackhole: <CALLER@thishost.test.ex> R=server
 1999-03-02 09:44:33 10HmbE-0005vi-00 Completed
 1999-03-02 09:44:33 exim x.yz daemon started: pid=pppp, no queue runs, listening for SMTP on port 1225
-1999-03-02 09:44:33 10HmbG-0005vi-00 <= CALLER@myhost.test.ex H=localhost (myhost.test.ex) [127.0.0.1] P=esmtps X=TLSv1:AES256-SHA:256 CV=no S=sss id=E10HmbF-0005vi-00@myhost.test.ex for CALLER@thishost.test.ex
+1999-03-02 09:44:33 10HmbG-0005vi-00 <= <> H=localhost (myhost.test.ex) [127.0.0.1] P=esmtps X=TLSv1:AES256-SHA:256 CV=no S=sss id=E10HmbF-0005vi-00@myhost.test.ex for CALLER@thishost.test.ex
 1999-03-02 09:44:33 10HmbG-0005vi-00 => :blackhole: <CALLER@thishost.test.ex> R=server
 1999-03-02 09:44:33 10HmbG-0005vi-00 Completed
 1999-03-02 09:44:33 exim x.yz daemon started: pid=pppp, no queue runs, listening for SMTP on port 1225
-1999-03-02 09:44:33 10HmbK-0005vi-00 <= CALLER@myhost.test.ex H=localhost (myhost.test.ex) [127.0.0.1] P=esmtps X=TLSv1:AES256-SHA:256 CV=no S=sss id=E10HmbH-0005vi-00@myhost.test.ex for CALLER@mxdanelazy.test.ex
-1999-03-02 09:44:33 10HmbK-0005vi-00 => :blackhole: <CALLER@mxdanelazy.test.ex> R=server
-1999-03-02 09:44:33 10HmbK-0005vi-00 Completed
-1999-03-02 09:44:33 10HmbM-0005vi-00 <= CALLER@myhost.test.ex H=localhost (myhost.test.ex) [127.0.0.1] P=esmtps X=TLSv1:AES256-SHA:256 CV=no S=sss id=E10HmbJ-0005vi-00@myhost.test.ex for CALLER@dane.no.2.test.ex
-1999-03-02 09:44:33 10HmbM-0005vi-00 => :blackhole: <CALLER@dane.no.2.test.ex> R=server
-1999-03-02 09:44:33 10HmbM-0005vi-00 Completed