ph10 2007/01/17 11:17:59 GMT
Modified files:
exim-doc/doc-txt ChangeLog NewStuff
exim-src ACKNOWLEDGMENTS
exim-src/src verify.c
exim-test/confs 0139
exim-test/scripts/0000-Basic 0139
exim-test/stderr 0139
exim-test/stdout 0139
Log:
Fix negated dnslists item bug; add == and =& features, courtesy Brad
Jorsch.
Revision Changes Path
1.454 +13 -0 exim/exim-doc/doc-txt/ChangeLog
1.127 +68 -0 exim/exim-doc/doc-txt/NewStuff
1.68 +2 -1 exim/exim-src/ACKNOWLEDGMENTS
1.46 +79 -32 exim/exim-src/src/verify.c
1.3 +17 -0 exim/exim-test/confs/0139
1.3 +8 -0 exim/exim-test/scripts/0000-Basic/0139
1.3 +101 -0 exim/exim-test/stderr/0139
1.3 +16 -0 exim/exim-test/stdout/0139
Index: ChangeLog
===================================================================
RCS file: /home/cvs/exim/exim-doc/doc-txt/ChangeLog,v
retrieving revision 1.453
retrieving revision 1.454
diff -u -r1.453 -r1.454
--- ChangeLog 16 Jan 2007 21:00:29 -0000 1.453
+++ ChangeLog 17 Jan 2007 11:17:58 -0000 1.454
@@ -1,4 +1,4 @@
-$Cambridge: exim/exim-doc/doc-txt/ChangeLog,v 1.453 2007/01/16 21:00:29 magnus Exp $
+$Cambridge: exim/exim-doc/doc-txt/ChangeLog,v 1.454 2007/01/17 11:17:58 ph10 Exp $
Change log file for Exim from version 4.21
-------------------------------------------
@@ -12,6 +12,19 @@
PH/01 Added a new log selector smtp_no_mail, to log SMTP sessions that do not
issue a MAIL command.
+
+PH/02 In an ACL statement such as
+
+ deny dnslists = X!=127.0.0.2 : X=127.0.0.2
+
+ if a client was not listed at all, or was listed with a value other than
+ 127.0.0.2, in the X list, but was listed with 127.0.0.2 in the Y list,
+ the condition was not true (as it should be), so access was not denied.
+ The bug was that the ! inversion was incorrectly passed on to the second
+ item. This has been fixed.
+
+PH/03 Added additional dnslists conditions == and =& which are different from
+ = and & when the dns lookup returns more than one IP address.
Exim version 4.66
Index: NewStuff
===================================================================
RCS file: /home/cvs/exim/exim-doc/doc-txt/NewStuff,v
retrieving revision 1.126
retrieving revision 1.127
diff -u -r1.126 -r1.127
--- NewStuff 15 Jan 2007 15:59:22 -0000 1.126
+++ NewStuff 17 Jan 2007 11:17:58 -0000 1.127
@@ -1,4 +1,4 @@
-$Cambridge: exim/exim-doc/doc-txt/NewStuff,v 1.126 2007/01/15 15:59:22 ph10 Exp $
+$Cambridge: exim/exim-doc/doc-txt/NewStuff,v 1.127 2007/01/17 11:17:58 ph10 Exp $
New Features in Exim
--------------------
@@ -37,6 +37,74 @@
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 =&.
Version 4.66
Index: ACKNOWLEDGMENTS
===================================================================
RCS file: /home/cvs/exim/exim-src/ACKNOWLEDGMENTS,v
retrieving revision 1.67
retrieving revision 1.68
diff -u -r1.67 -r1.68
--- ACKNOWLEDGMENTS 19 Dec 2006 14:51:34 -0000 1.67
+++ ACKNOWLEDGMENTS 17 Jan 2007 11:17:58 -0000 1.68
@@ -1,4 +1,4 @@
-$Cambridge: exim/exim-src/ACKNOWLEDGMENTS,v 1.67 2006/12/19 14:51:34 ph10 Exp $
+$Cambridge: exim/exim-src/ACKNOWLEDGMENTS,v 1.68 2007/01/17 11:17:58 ph10 Exp $
EXIM ACKNOWLEDGEMENTS
@@ -20,7 +20,7 @@
Philip Hazel
Lists created: 20 November 2002
-Last updated: 19 December 2006
+Last updated: 17 January 2007
THE OLD LIST
@@ -178,6 +178,7 @@
Patch for negative uid/gid bug
Brad Jorsch Patch for bitwise logical operators
Patch for using "message" on acceptance
+ Patch to add == and =& to dnslists
Christian Kellner Patch for LDAP dereferencing
Alex Kiernan Patches for libradius
Diagnosis of milliwait clock-backwards bug
Index: verify.c
===================================================================
RCS file: /home/cvs/exim/exim-src/src/verify.c,v
retrieving revision 1.45
retrieving revision 1.46
diff -u -r1.45 -r1.46
--- verify.c 8 Jan 2007 10:50:18 -0000 1.45
+++ verify.c 17 Jan 2007 11:17:58 -0000 1.46
@@ -1,4 +1,4 @@
-/* $Cambridge: exim/exim-src/src/verify.c,v 1.45 2007/01/08 10:50:18 ph10 Exp $ */
+/* $Cambridge: exim/exim-src/src/verify.c,v 1.46 2007/01/17 11:17:58 ph10 Exp $ */
/*************************************************
* Exim - an Internet mail transport agent *
@@ -29,6 +29,12 @@
static tree_node *dnsbl_cache = NULL;
+/* Bits for match_type in one_check_dnsbl() */
+
+#define MT_NOT 1
+#define MT_ALL 2
+
+
/*************************************************
* Retrieve a callout cache record *
@@ -2540,7 +2546,12 @@
reversed if IP address)
iplist the list of matching IP addresses, or NULL for "any"
bitmask true if bitmask matching is wanted
- invert_result true if result to be inverted
+ match_type condition for 'succeed' result
+ 0 => Any RR in iplist (=)
+ 1 => No RR in iplist (!=)
+ 2 => All RRs in iplist (==)
+ 3 => Some RRs not in iplist (!==)
+ the two bits are defined as MT_NOT and MT_ALL
defer_return what to return for a defer
Returns: OK if lookup succeeded
@@ -2549,7 +2560,7 @@
static int
one_check_dnsbl(uschar *domain, uschar *domain_txt, uschar *keydomain,
- uschar *prepend, uschar *iplist, BOOL bitmask, BOOL invert_result,
+ uschar *prepend, uschar *iplist, BOOL bitmask, int match_type,
int defer_return)
{
dns_answer dnsa;
@@ -2668,21 +2679,25 @@
if (iplist != NULL)
{
- int ipsep = ',';
- uschar ip[46];
- uschar *ptr = iplist;
-
- while (string_nextinlist(&ptr, &ipsep, ip, sizeof(ip)) != NULL)
+ for (da = cb->rhs; da != NULL; da = da->next)
{
+ int ipsep = ',';
+ uschar ip[46];
+ uschar *ptr = iplist;
+ uschar *res;
+
/* Handle exact matching */
+
if (!bitmask)
{
- for (da = cb->rhs; da != NULL; da = da->next)
+ while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))) != NULL)
{
if (Ustrcmp(CS da->address, ip) == 0) break;
}
}
+
/* Handle bitmask matching */
+
else
{
int address[4];
@@ -2695,37 +2710,60 @@
ignore IPv6 addresses. The default mask is 0, which always matches.
We change this only for IPv4 addresses in the list. */
- if (host_aton(ip, address) == 1) mask = address[0];
+ if (host_aton(da->address, address) == 1) mask = address[0];
/* Scan the returned addresses, skipping any that are IPv6 */
- for (da = cb->rhs; da != NULL; da = da->next)
+ while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))) != NULL)
{
- if (host_aton(da->address, address) != 1) continue;
- if ((address[0] & mask) == mask) break;
+ if (host_aton(ip, address) != 1) continue;
+ if ((address[0] & mask) == address[0]) break;
}
}
- /* Break out if a match has been found */
+ /* If either
+
+ (a) An IP address in an any ('=') list matched, or
+ (b) No IP address in an all ('==') list matched
- if (da != NULL) break;
+ then we're done searching. */
+
+ if (((match_type & MT_ALL) != 0) == (res == NULL)) break;
}
- /* If either
+ /* If da == NULL, either
- (a) No IP address in a positive list matched, or
- (b) An IP address in a negative list did match
+ (a) No IP address in an any ('=') list matched, or
+ (b) An IP address in an all ('==') list didn't match
- then behave as if the DNSBL lookup had not succeeded, i.e. the host is
- not on the list. */
+ so behave as if the DNSBL lookup had not succeeded, i.e. the host is not on
+ the list. */
- if (invert_result != (da == NULL))
+ if ((match_type == MT_NOT || match_type == MT_ALL) != (da == NULL))
{
HDEBUG(D_dnsbl)
{
+ uschar *res = NULL;
+ switch(match_type)
+ {
+ case 0:
+ res = US"was no match";
+ break;
+ case MT_NOT:
+ res = US"was an exclude match";
+ break;
+ case MT_ALL:
+ res = US"was an IP address that did not match";
+ break;
+ case MT_NOT|MT_ALL:
+ res = US"were no IP addresses that did not match";
+ break;
+ }
debug_printf("=> but we are not accepting this block class because\n");
- debug_printf("=> there was %s match for %c%s\n",
- invert_result? "an exclude":"no", bitmask? '&' : '=', iplist);
+ debug_printf("=> there %s for %s%c%s\n",
+ res,
+ ((match_type & MT_ALL) == 0)? "" : "=",
+ bitmask? '&' : '=', iplist);
}
return FAIL;
}
@@ -2739,7 +2777,7 @@
if (domain_txt != domain)
return one_check_dnsbl(domain_txt, domain_txt, keydomain, prepend, NULL,
- FALSE, invert_result, defer_return);
+ FALSE, match_type, defer_return);
/* If there is no alternate domain, look up a TXT record in the main domain
if it has not previously been cached. */
@@ -2852,7 +2890,6 @@
{
int sep = 0;
int defer_return = FAIL;
-BOOL invert_result = FALSE;
uschar *list = *listptr;
uschar *domain;
uschar *s;
@@ -2873,6 +2910,7 @@
{
int rc;
BOOL bitmask = FALSE;
+ int match_type = 0;
uschar *domain_txt;
uschar *comma;
uschar *iplist;
@@ -2899,8 +2937,8 @@
if (key != NULL) *key++ = 0;
/* See if there's a list of addresses supplied after the domain name. This is
- introduced by an = or a & character; if preceded by ! we invert the result.
- */
+ introduced by an = or a & character; if preceded by = we require all matches
+ and if preceded by ! we invert the result. */
iplist = Ustrchr(domain, '=');
if (iplist == NULL)
@@ -2909,14 +2947,23 @@
iplist = Ustrchr(domain, '&');
}
- if (iplist != NULL)
+ if (iplist != NULL) /* Found either = or & */
{
- if (iplist > domain && iplist[-1] == '!')
+ if (iplist > domain && iplist[-1] == '!') /* Handle preceding ! */
{
- invert_result = TRUE;
+ match_type |= MT_NOT;
iplist[-1] = 0;
}
- *iplist++ = 0;
+
+ *iplist++ = 0; /* Terminate domain, move on */
+
+ /* If we found = (bitmask == FALSE), check for == or =& */
+
+ if (!bitmask && (*iplist == '=' || *iplist == '&'))
+ {
+ bitmask = *iplist++ == '&';
+ match_type |= MT_ALL;
+ }
}
/* If there is a comma in the domain, it indicates that a second domain for
@@ -2967,7 +3014,7 @@
if (sender_host_address == NULL) return FAIL; /* can never match */
if (revadd[0] == 0) invert_address(revadd, sender_host_address);
rc = one_check_dnsbl(domain, domain_txt, sender_host_address, revadd,
- iplist, bitmask, invert_result, defer_return);
+ iplist, bitmask, match_type, defer_return);
if (rc == OK)
{
dnslist_domain = string_copy(domain_txt);
@@ -3000,7 +3047,7 @@
}
rc = one_check_dnsbl(domain, domain_txt, keydomain, prepend, iplist,
- bitmask, invert_result, defer_return);
+ bitmask, match_type, defer_return);
if (rc == OK)
{
Index: 0139
===================================================================
RCS file: /home/cvs/exim/exim-test/confs/0139,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -r1.2 -r1.3
--- 0139 3 Oct 2006 15:11:22 -0000 1.2
+++ 0139 17 Jan 2007 11:17:59 -0000 1.3
@@ -13,12 +13,29 @@
domainlist local_domains = exim.test.ex
trusted_users = CALLER
+acl_smtp_helo = check_helo
acl_smtp_rcpt = check_recipient
acl_smtp_mail = check_mail
+acl_smtp_vrfy = check_vrfy
# ------ ACL ------
begin acl
+
+check_helo:
+ warn dnslists = rbl2.test.ex!=127.0.0.3 : rbl3.test.ex=127.0.0.3
+ accept
+
+check_vrfy:
+ warn dnslists = rbl.test.ex=127.0.0.1
+ warn dnslists = rbl.test.ex!=127.0.0.1
+ warn dnslists = rbl.test.ex!=127.0.0.3
+ warn dnslists = rbl.test.ex==127.0.0.1
+ warn dnslists = rbl.test.ex==127.0.0.1,127.0.0.2
+ warn dnslists = rbl.test.ex!==127.0.0.1
+ warn dnslists = rbl.test.ex!==127.0.0.3
+ warn dnslists = rbl.test.ex!==127.0.0.1,127.0.0.2
+ accept
check_mail:
warn dnslists = rbl4.test.ex&0.0.0.6
Index: 0139
===================================================================
RCS file: /home/cvs/exim/exim-test/scripts/0000-Basic/0139,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -r1.2 -r1.3
--- 0139 3 Oct 2006 15:11:22 -0000 1.2
+++ 0139 17 Jan 2007 11:17:59 -0000 1.3
@@ -32,4 +32,12 @@
.
quit
****
+exim -bh V4NET.11.12.15
+helo a.b
+quit
+****
+exim -bh V4NET.13.13.2
+vrfy a@b
+quit
+****
no_msglog_check
Index: 0139
===================================================================
RCS file: /home/cvs/exim/exim-test/stderr/0139,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -r1.2 -r1.3
--- 0139 3 Oct 2006 15:11:22 -0000 1.2
+++ 0139 17 Jan 2007 11:17:59 -0000 1.3
@@ -259,3 +259,104 @@
>>> warn: condition test failed
>>> processing "accept"
>>> accept: condition test succeeded
+>>> host in hosts_connection_nolog? no (option unset)
+>>> host in host_lookup? no (option unset)
+>>> host in host_reject_connection? no (option unset)
+>>> host in sender_unqualified_hosts? no (option unset)
+>>> host in recipient_unqualified_hosts? no (option unset)
+>>> host in helo_verify_hosts? no (option unset)
+>>> host in helo_try_verify_hosts? no (option unset)
+>>> host in helo_accept_junk_hosts? no (option unset)
+>>> a.b in helo_lookup_domains? no (end of list)
+>>> using ACL "check_helo"
+>>> processing "warn"
+>>> check dnslists = rbl2.test.ex!=127.0.0.3 : rbl3.test.ex=127.0.0.3
+>>> DNS list check: rbl2.test.ex!=127.0.0.3
+>>> new DNS lookup for 15.12.11.V4NET.rbl2.test.ex
+>>> DNS lookup for 15.12.11.V4NET.rbl2.test.ex failed
+>>> => that means V4NET.11.12.15 is not listed at rbl2.test.ex
+>>> DNS list check: rbl3.test.ex=127.0.0.3
+>>> new DNS lookup for 15.12.11.V4NET.rbl3.test.ex
+>>> DNS lookup for 15.12.11.V4NET.rbl3.test.ex succeeded (yielding 127.0.0.3)
+>>> => that means V4NET.11.12.15 is listed at rbl3.test.ex
+>>> warn: condition test succeeded
+>>> processing "accept"
+>>> accept: condition test succeeded
+>>> host in hosts_connection_nolog? no (option unset)
+>>> host in host_lookup? no (option unset)
+>>> host in host_reject_connection? no (option unset)
+>>> host in sender_unqualified_hosts? no (option unset)
+>>> host in recipient_unqualified_hosts? no (option unset)
+>>> host in helo_verify_hosts? no (option unset)
+>>> host in helo_try_verify_hosts? no (option unset)
+>>> host in helo_accept_junk_hosts? no (option unset)
+>>> host in smtp_accept_max_nonmail_hosts? yes (matched "*")
+>>> using ACL "check_vrfy"
+>>> processing "warn"
+>>> check dnslists = rbl.test.ex=127.0.0.1
+>>> DNS list check: rbl.test.ex=127.0.0.1
+>>> new DNS lookup for 2.13.13.V4NET.rbl.test.ex
+>>> DNS lookup for 2.13.13.V4NET.rbl.test.ex succeeded (yielding 127.0.0.1, 127.0.0.2)
+>>> => that means V4NET.13.13.2 is listed at rbl.test.ex
+>>> warn: condition test succeeded
+>>> processing "warn"
+>>> check dnslists = rbl.test.ex!=127.0.0.1
+>>> DNS list check: rbl.test.ex!=127.0.0.1
+>>> using result of previous DNS lookup
+>>> DNS lookup for 2.13.13.V4NET.rbl.test.ex succeeded (yielding 127.0.0.1, 127.0.0.2)
+>>> => but we are not accepting this block class because
+>>> => there was an exclude match for =127.0.0.1
+>>> warn: condition test failed
+>>> processing "warn"
+>>> check dnslists = rbl.test.ex!=127.0.0.3
+>>> DNS list check: rbl.test.ex!=127.0.0.3
+>>> using result of previous DNS lookup
+>>> DNS lookup for 2.13.13.V4NET.rbl.test.ex succeeded (yielding 127.0.0.1, 127.0.0.2)
+>>> => that means V4NET.13.13.2 is listed at rbl.test.ex
+>>> warn: condition test succeeded
+>>> processing "warn"
+>>> check dnslists = rbl.test.ex==127.0.0.1
+>>> DNS list check: rbl.test.ex==127.0.0.1
+>>> using result of previous DNS lookup
+>>> DNS lookup for 2.13.13.V4NET.rbl.test.ex succeeded (yielding 127.0.0.1, 127.0.0.2)
+>>> => but we are not accepting this block class because
+>>> => there was an IP address that did not match for ==127.0.0.1
+>>> warn: condition test failed
+>>> processing "warn"
+>>> check dnslists = rbl.test.ex==127.0.0.1,127.0.0.2
+>>> DNS list check: rbl.test.ex==127.0.0.1,127.0.0.2
+>>> using result of previous DNS lookup
+>>> DNS lookup for 2.13.13.V4NET.rbl.test.ex succeeded (yielding 127.0.0.1, 127.0.0.2)
+>>> => that means V4NET.13.13.2 is listed at rbl.test.ex
+>>> warn: condition test succeeded
+>>> processing "warn"
+>>> check dnslists = rbl.test.ex!==127.0.0.1
+>>> DNS list check: rbl.test.ex!==127.0.0.1
+>>> using result of previous DNS lookup
+>>> DNS lookup for 2.13.13.V4NET.rbl.test.ex succeeded (yielding 127.0.0.1, 127.0.0.2)
+>>> => that means V4NET.13.13.2 is listed at rbl.test.ex
+>>> warn: condition test succeeded
+>>> processing "warn"
+>>> check dnslists = rbl.test.ex!==127.0.0.3
+>>> DNS list check: rbl.test.ex!==127.0.0.3
+>>> using result of previous DNS lookup
+>>> DNS lookup for 2.13.13.V4NET.rbl.test.ex succeeded (yielding 127.0.0.1, 127.0.0.2)
+>>> => that means V4NET.13.13.2 is listed at rbl.test.ex
+>>> warn: condition test succeeded
+>>> processing "warn"
+>>> check dnslists = rbl.test.ex!==127.0.0.1,127.0.0.2
+>>> DNS list check: rbl.test.ex!==127.0.0.1,127.0.0.2
+>>> using result of previous DNS lookup
+>>> DNS lookup for 2.13.13.V4NET.rbl.test.ex succeeded (yielding 127.0.0.1, 127.0.0.2)
+>>> => but we are not accepting this block class because
+>>> => there were no IP addresses that did not match for ==127.0.0.1,127.0.0.2
+>>> warn: condition test failed
+>>> processing "accept"
+>>> accept: condition test succeeded
+>>> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+>>> routing a@b
+>>> calling system_aliases router
+>>> system_aliases router declined for a@b
+>>> a in "userx"? no (end of list)
+>>> no more routers
+LOG: VRFY failed for a@b H=[V4NET.13.13.2]
Index: 0139
===================================================================
RCS file: /home/cvs/exim/exim-test/stdout/0139,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -r1.2 -r1.3
--- 0139 3 Oct 2006 15:11:22 -0000 1.2
+++ 0139 17 Jan 2007 11:17:59 -0000 1.3
@@ -50,3 +50,19 @@
354 Enter message, ending with "." on a line by itself
250 OK id=10HmaX-0005vi-00
221 the.local.host.name closing connection
+
+**** SMTP testing session as if from host V4NET.11.12.15
+**** but without any ident (RFC 1413) callback.
+**** This is not for real!
+
+220 the.local.host.name ESMTP Exim x.yz Tue, 2 Mar 1999 09:44:33 +0000
+250 the.local.host.name Hello a.b [V4NET.11.12.15]
+221 the.local.host.name closing connection
+
+**** SMTP testing session as if from host V4NET.13.13.2
+**** but without any ident (RFC 1413) callback.
+**** This is not for real!
+
+220 the.local.host.name ESMTP Exim x.yz Tue, 2 Mar 1999 09:44:33 +0000
+550 <a@b> Unrouteable address
+221 the.local.host.name closing connection
