See https://free.acrconsulting.co.uk/email/qmail-verify.html for info on this patch
diff --git a/Makefile b/Makefile
index a27a809..69d401d 100644
--- a/Makefile
+++ b/Makefile
@@ -812,7 +812,7 @@ dnsptr dnsip dnsmxip dnsfq hostname ipmeprint qreceipt qsmhook qbiff \
 forward preline condredirect bouncesaying except maildirmake \
 maildir2mbox maildirwatch qail elq pinq idedit install-big install \
 instcheck home home+df proc proc+df binm1 binm1+df binm2 binm2+df \
-binm3 binm3+df
+binm3 binm3+df qmail-verify
 
 load: \
 make-load warn-auto.sh systype
@@ -939,7 +939,7 @@ preline.0 condredirect.0 bouncesaying.0 except.0 maildirmake.0 \
 maildir2mbox.0 maildirwatch.0 qmail.0 qmail-limits.0 qmail-log.0 \
 qmail-control.0 qmail-header.0 qmail-users.0 dot-qmail.0 \
 qmail-command.0 tcp-environ.0 maildir.0 mbox.0 addresses.0 \
-envelopes.0 forgeries.0
+envelopes.0 forgeries.0 qmail-verify.0
 
 mbox.0: \
 mbox.5
@@ -1537,14 +1537,19 @@ auto_split.h
 
 qmail-smtpd: \
 load qmail-smtpd.o rcpthosts.o commands.o timeoutread.o \
+sockbits.o udpbits.o verifyrcpt.o \
 timeoutwrite.o ip.o ipme.o ipalloc.o control.o constmap.o received.o \
-date822fmt.o now.o qmail.o cdb.a fd.a wait.a datetime.a getln.a \
+date822fmt.o now.o qmail.o cdb.a fd.a wait.a \
+scan_misc.o \
+datetime.a getln.a \
 open.a sig.a case.a env.a stralloc.a errbits.o \
 alloc.a substdio.a error.a str.a \
 fs.a auto_qmail.o socket.lib
 	./load qmail-smtpd rcpthosts.o commands.o timeoutread.o \
+	sockbits.o udpbits.o verifyrcpt.o \
 	timeoutwrite.o ip.o ipme.o ipalloc.o control.o constmap.o \
 	received.o date822fmt.o now.o qmail.o cdb.a fd.a wait.a \
+	scan_misc.o \
 	datetime.a getln.a open.a sig.a case.a env.a stralloc.a \
 	errbits.o \
 	alloc.a substdio.a error.a str.a fs.a auto_qmail.o  `cat \
@@ -1559,6 +1564,7 @@ compile qmail-smtpd.c sig.h readwrite.h stralloc.h gen_alloc.h \
 substdio.h alloc.h auto_qmail.h control.h received.h constmap.h \
 error.h ipme.h ip.h ipalloc.h ip.h gen_alloc.h ip.h qmail.h \
 substdio.h str.h fmt.h scan.h byte.h case.h env.h now.h datetime.h \
+sockbits.h udpbits.h qmail-verify.h \
 exit.h rcpthosts.h timeoutread.h timeoutwrite.h commands.h
 	./compile qmail-smtpd.c
 
@@ -1633,6 +1639,31 @@ qmail-users.9 conf-break conf-spawn
 	| sed s}SPAWN}"`head -1 conf-spawn`"}g \
 	> qmail-users.5
 
+qmail-verify.o: \
+qmail-verify.h compile qmail-verify.c auto_break.h auto_usera.h auto_qmail.h byte.h case.h cdb.h \
+constmap.h error.h fmt.h ip.h open.h str.h stralloc.h uint32.h errbits.h
+	./compile qmail-verify.c
+
+qmail-verify: \
+load qmail-verify.o timeoutread.o \
+timeoutwrite.o control.o ip.o constmap.o \
+cdb.a fd.a wait.a getln.a \
+open.a sig.a case.a env.a stralloc.a \
+auto_usera.o auto_break.o auto_qmail.o errbits.o \
+alloc.a substdio.a error.a str.a fs.a \
+socket.lib
+	./load qmail-verify timeoutread.o \
+	timeoutwrite.o control.o ip.o constmap.o \
+	cdb.a fd.a wait.a \
+	getln.a open.a sig.a case.a env.a stralloc.a \
+	auto_usera.o auto_break.o auto_qmail.o errbits.o \
+	alloc.a substdio.a error.a str.a fs.a `cat \
+	socket.lib`
+
+qmail-verify.0: \
+qmail-verify.8
+	nroff -man qmail-verify.8 > qmail-verify.0
+
 qmail.0: \
 qmail.7
 	nroff -man qmail.7 > qmail.0
@@ -1706,6 +1737,10 @@ scan_8long.o: \
 compile scan_8long.c scan.h
 	./compile scan_8long.c
 
+scan_misc.o: \
+compile scan_misc.c scan.h
+	./compile scan_misc.c
+
 scan_ulong.o: \
 compile scan_ulong.c scan.h
 	./compile scan_ulong.c
@@ -1777,6 +1812,7 @@ qmail-lspawn.8 qmail-newmrh.9 qmail-newu.9 qmail-pop3d.8 \
 qmail-popup.8 qmail-pw2u.9 qmail-qmqpc.8 qmail-qmqpd.8 qmail-qmtpd.8 \
 qmail-qread.8 qmail-qstat.8 qmail-queue.8 qmail-remote.8 \
 qmail-rspawn.8 qmail-send.9 qmail-showctl.8 qmail-smtpd.8 \
+qmail-verify.8 \
 qmail-start.9 qmail-tcpok.8 qmail-tcpto.8 qmail-users.9 qmail.7 \
 qreceipt.1 splogger.8 tcp-env.1 config.sh config-fast.sh \
 qmail-clean.c qmail-getpw.c qmail-inject.c qmail-local.c \
@@ -1889,6 +1925,10 @@ compile slurpclose.c stralloc.h gen_alloc.h readwrite.h slurpclose.h \
 error.h
 	./compile slurpclose.c
 
+sockbits.o: \
+compile sockbits.c sockbits.h stralloc.h gen_alloc.h
+	./compile sockbits.c
+
 socket.lib: \
 trylsock.c compile load
 	( ( ./compile trylsock.c && \
@@ -2127,6 +2167,10 @@ triggerpull.o: \
 compile triggerpull.c ndelay.h open.h triggerpull.h
 	./compile triggerpull.c
 
+udpbits.o: \
+compile udpbits.c udpbits.h ip.h
+	./compile udpbits.c
+
 uint32.h: \
 tryulong32.c compile load uint32.h1 uint32.h2
 	( ( ./compile tryulong32.c && ./load tryulong32 && \
@@ -2134,6 +2178,15 @@ tryulong32.c compile load uint32.h1 uint32.h2
 	&& cat uint32.h2 || cat uint32.h1 ) > uint32.h
 	rm -f tryulong32.o tryulong32
 
+verifyrcpt.o: \
+compile verifyrcpt.c verifyrcpt.h sig.h readwrite.h stralloc.h gen_alloc.h \
+substdio.h alloc.h auto_qmail.h control.h received.h constmap.h \
+error.h ipme.h ip.h ipalloc.h ip.h gen_alloc.h ip.h qmail.h \
+substdio.h str.h fmt.h scan.h byte.h case.h env.h now.h datetime.h \
+exit.h rcpthosts.h timeoutread.h timeoutwrite.h commands.h \
+sockbits.h udpbits.h qmail-verify.h
+	./compile verifyrcpt.c
+
 wait.a: \
 makelib wait_pid.o wait_nohang.o
 	./makelib wait.a wait_pid.o wait_nohang.o
diff --git a/TARGETS b/TARGETS
index 0dbad3e..1117464 100644
--- a/TARGETS
+++ b/TARGETS
@@ -251,8 +251,14 @@ qmail-qmqpd
 qmail-qmtpd.o
 rcpthosts.o
 qmail-qmtpd
+verifyrcpt.o
+sockbits.o
+udpbits.o
+scan_misc.o
 qmail-smtpd.o
 qmail-smtpd
+qmail-verify.o
+qmail-verify
 sendmail.o
 sendmail
 tcp-env.o
@@ -352,6 +358,7 @@ qmail-qmqpc.0
 qmail-qmqpd.0
 qmail-qmtpd.0
 qmail-smtpd.0
+qmail-verify.0
 tcp-env.0
 qmail-newmrh.8
 qmail-newmrh.0
diff --git a/hier.c b/hier.c
index 28e568d..6c6e929 100644
--- a/hier.c
+++ b/hier.c
@@ -127,6 +127,7 @@ void hier()
   c(auto_qmail,"bin","qmail-qmqpd",auto_uido,auto_gidq,0755);
   c(auto_qmail,"bin","qmail-qmtpd",auto_uido,auto_gidq,0755);
   c(auto_qmail,"bin","qmail-smtpd",auto_uido,auto_gidq,0755);
+  c(auto_qmail,"bin","qmail-verify",auto_uido,auto_gidq,0755);
   c(auto_qmail,"bin","sendmail",auto_uido,auto_gidq,0755);
   c(auto_qmail,"bin","tcp-env",auto_uido,auto_gidq,0755);
   c(auto_qmail,"bin","qreceipt",auto_uido,auto_gidq,0755);
@@ -249,4 +250,6 @@ void hier()
   c(auto_qmail,"man/cat8","qmail-smtpd.0",auto_uido,auto_gidq,0644);
   c(auto_qmail,"man/man8","qmail-command.8",auto_uido,auto_gidq,0644);
   c(auto_qmail,"man/cat8","qmail-command.0",auto_uido,auto_gidq,0644);
+  c(auto_qmail,"man/man8","qmail-verify.8",auto_uido,auto_gidq,0644);
+  c(auto_qmail,"man/cat8","qmail-verify.0",auto_uido,auto_gidq,0644);
 }
diff --git a/qmail-smtpd.8 b/qmail-smtpd.8
index c4640b8..77f24e4 100644
--- a/qmail-smtpd.8
+++ b/qmail-smtpd.8
@@ -169,6 +169,66 @@ Number of seconds
 .B qmail-smtpd
 will wait for each new buffer of data from the remote SMTP client.
 Default: 1200.
+.SH "RECIPIENT VERIFICATION"
+Recipient verification is enabled with the
+.B VERIFY
+environment variable. This can be used to specify per-recipient
+rejection of invalid recipient addresses (immediate verification
+causing a permanent 550 error response to the RCPT command),
+or deferred rejection at DATA time (554 response) of the whole
+session if any recipient addresses don't exist.
+
+To verify an address,
+.B qmail-smtpd
+uses a separate
+.B qmail-verify
+UDP server. By default this will be on the loopback address 127.0.0.1,
+port 11113. Enable verification like this,
+
+.EX
+   VERIFY=":"
+
+   VERIFY="DEFER"
+.EE
+
+(for immediate, deferred verification respectively). A different IP
+address and/or port can be specified for
+.B qmail-verify
+as in these examples,
+
+.EX
+   VERIFY="192.168.1.1"
+   VERIFY=":10101"
+   VERIFY="DEFER,:10101"
+   VERIFY="DEFER,192.168.1.1:10101"
+.EE
+
+Recipient verification may be explicitly disabled by setting
+.B VERIFY
+to an empty string,
+
+.EX
+   VERIFY=""
+.EE
+
+Addresses with domains appearing in
+.B control/rcpthosts
+but not in
+.B control/locals
+or
+.B control/virtualdomains
+will be considered valid, reflecting qmail's standard behaviour.
+.P
+Note that if the environment variable
+.B RELAYCLIENT
+is set, no checking is carried out.
+.P
+.B qmail-verify
+needs to be running to respond to recipient
+verification queries. If no
+.B qmail-verify
+response is received a temporary 451 error response is
+given to the remote system and the session terminated.
 .SH "SEE ALSO"
 tcp-env(1),
 tcp-environ(5),
@@ -176,4 +236,5 @@ qmail-control(5),
 qmail-inject(8),
 qmail-newmrh(8),
 qmail-queue(8),
-qmail-remote(8)
+qmail-remote(8),
+qmail-verify(8)
diff --git a/qmail-smtpd.c b/qmail-smtpd.c
index f863012..1005b5a 100644
--- a/qmail-smtpd.c
+++ b/qmail-smtpd.c
@@ -24,6 +24,7 @@
 #include "timeoutwrite.h"
 #include "commands.h"
 #include "errbits.h"
+#include "verifyrcpt.h"
 
 #define enew()	{ eout("qmail-smtpd: pid "); epid(); eout3(" from ",remoteip,": "); }
 /* Or if you prefer shorter log messages (deduce IP from tcpserver PID entry), */
@@ -37,6 +38,8 @@ char *remotehost;
 char *remoteinfo;
 char *local;
 char *relayclient;
+char *verify;
+int verifydefer=0;
 
 stralloc mailfrom = {0};
 stralloc rcptto = {0};
@@ -146,6 +149,31 @@ void err_databytes()
   enew(); eout("Exceeded DATABYTES limit\n"); eflush();
   out("552 sorry, that message size exceeds my databytes limit (#5.3.4)\r\n");
 }
+void die_qvsetup()
+{
+  enew(); eout3("setup failure (",error_str(errno),")\n"); eflush();
+  out("451 qv setup failure (#4.3.0)\r\n"); flush(); _exit(1);
+}
+void die_qvtimeout()
+{
+  enew(); eout("Timeout (no response from verification server)\n"); eflush();
+  out("451 qv temporary failure (#4.3.0)\r\n"); flush(); _exit(1);
+}
+void die_qvmiscfail()
+{
+  enew(); eout3("temporary failure (",error_str(errno),")\n"); eflush();
+  out("451 qv temporary failure (#4.3.0)\r\n"); flush(); _exit(1);
+}
+void err_nosuchuser550()
+{
+  enew(); eout("Unverified mailbox at RCPT time\n"); eflush();
+  out("550 sorry, no mailbox here by that name. (#5.1.1)\r\n");
+}
+void err_nosuchuser554()
+{
+  enew(); eout("Unverified mailbox(es) at DATA time\n"); eflush();
+  out("554 sorry, invalid mailbox name(s). (#5.1.1)\r\n");
+}
 
 
 stralloc greeting = {0};
@@ -214,6 +242,18 @@ void setup()
   if (!remotehost) remotehost = "unknown";
   remoteinfo = env_get("TCPREMOTEINFO");
   relayclient = env_get("RELAYCLIENT");
+  verify =  env_get("VERIFY");
+  if (verify)
+  {
+    if (*verify == '\0') /* Disable verification if VERIFY="" */
+    {
+      verify = 0; 
+      /* Warning message since previous version of qmail-verify used VERIFY="" to enable verification */
+      enew(); eout("Note recipient verification explicitly disabled.\n"); eflush();
+    }
+    else
+      if ((*verify == 'D') || (*verify == 'd')) verifydefer=1;
+  }
   dohelo(remotehost);
   enew(); eout("New session\n"); eflush();
 }
@@ -316,6 +356,7 @@ void smtp_ehlo(arg) char *arg;
 }
 void smtp_rset(arg) char *arg;
 {
+  flagdenyany = 0;
   seenmail = 0;
   enew(); eout("Session RSET\n"); eflush();
   out("250 flushed\r\n");
@@ -342,7 +383,14 @@ void smtp_rcpt(arg) char *arg; {
     if (!stralloc_0(&addr)) die_nomem();
   }
   else
+  {
     if (!addrallowed()) { err_nogateway(); return; }
+    if (verify && verifyrcpt(find_digit_colon_eos(verify),&addr,verifydefer,die_qvtimeout,die_qvmiscfail))
+    {
+      err_nosuchuser550();
+      return;
+    }
+  }
   if (!stralloc_cats(&rcptto,"T")) die_nomem();
   if (!stralloc_cats(&rcptto,addr.s)) die_nomem();
   if (!stralloc_0(&rcptto)) die_nomem();
@@ -465,6 +513,7 @@ void smtp_data(arg) char *arg; {
  
   if (!seenmail) { err_wantmail(); return; }
   if (!rcptto.len) { err_wantrcpt(); return; }
+  if (verifydefer && flagdenyany) { err_nosuchuser554(); return; }
   seenmail = 0;
   if (databytes) bytestooverflow = databytes + 1;
   messagebytes = 0;
diff --git a/qmail-verify.8 b/qmail-verify.8
new file mode 100644
index 0000000..6b46e5c
--- /dev/null
+++ b/qmail-verify.8
@@ -0,0 +1,138 @@
+.TH qmail-verify 8 "Andrew Richards" "14th May 2020" "v1.50"
+.SH NAME
+qmail-verify \- Address verification daemon
+.SH SYNOPSIS
+.B qmail-verify
+.SH DESCRIPTION
+.B qmail-verify
+receives UDP packets containing local email addresses and replies
+to indicate if the address is valid.
+.B qmail-smtpd
+or
+.B qmail-qmtpd
+are typical clients using the
+.B qmail-verify
+service, although at present only
+.B qmail-smtpd
+has had this functionality added.
+.B qmail-verify
+is based on Paul Jarc's
+.B realrcptto
+patch for qmail
+.I (http://code.dogmap.org/qmail/).
+
+.B qmail-verify
+uses the files
+.I control/me, control/envnoathost, control/locals, control/percenthack, control/virtualdomains, users/cdb,
+the system password file entries (typically in
+.B /etc/passwd
+) as well as the existence or not of users' home directories and
+.B .qmail[-xxx]
+files to determine if a given address is valid.
+
+Where a qmail system uses
+.B .qmail-default
+files on a per-domain basis in a virtual domains setup, this is
+likely to result in all addresses being considered 'valid'. This
+may not in fact be the case in certain situations, such as with
+extensions/adaptations to qmail like vpopmail which use
+.B .qmail-default
+files throughout (delivery in this case is subsequently handled
+by a vpopmail component). In these cases a replacement for
+.B qmail-verify
+will be required that can determine address validity.
+
+Other customised qmail installations that use different methods
+to locate users' mailboxes are likely to need alternatives to
+.B qmail-verify
+or a modified version of it for address verification.
+
+.SH INVOCATION
+.B qmail-verify
+should be invoked as user
+.I root
+to have sufficient privileges to
+determine the validity of a given address. In certain single-UID
+virtual domains setups, it may be sufficient to run
+.B qmail-verify
+as the single-UID.
+
+By default,
+.B qmail-verify
+listens on localhost (127.0.0.1) on port 11113. This behaviour
+can be changed by setting the environment variable
+.B LISTEN
+to specify the IP address and/or port: Set this to the desired
+IP address, optionally followed by a colon and port, thus for
+example LISTEN="192.168.1.1:10101".
+
+.SH ADDRESS VERIFICATION DETAILS
+.B qmail-verify
+is implemented by taking the various pieces of qmail that parse an
+address and combining them in the same executable,
+.B qmail-verify.
+Thus logic is taken from
+.B qmail-send, qmail-lspawn, qmail-getpw
+and
+.B qmail-local.
+
+.SH "UDP PACKET DETAILS"
+The incoming packet contains just the email address to be checked
+as a string. The string is optionally terminated with a 0 byte.
+
+The response packet contains a single byte to indicate the validity
+of the address and a string, the 'controlling user', i.e. system
+user that owns the mailbox for the address being tested. The
+lowest-order bit of this byte indicates the result:
+.B 0
+for 'valid',
+.B 1
+for 'invalid'. Other bits of this response byte are set by
+.B qmail-verify
+to give further debugging information; these other bits should
+generally be disregarded.
+
+Although not especially designed as a new protocol, extensions to
+.B qmail-verify
+could require the query string to be 0 terminated
+to separate it from other data to follow. Currently the response packet
+contains the response byte and the 'Controlling user'; more
+information could potentially be returned if required.
+
+.SH CONTROL FILES
+At startup
+.B qmail-verify
+reads the following qmail control files:
+.I control/me, control/envnoathost, control/locals, control/percenthack, control/virtualdomains.
+If changes are made to any of these files,
+.B qmail-verify
+should be restarted for the changes to take effect in
+.B qmail-verify.
+
+If you are using different machines for
+.B qmail-verify
+and
+.B qmail-smtpd
+you should ensure that the machine providing the
+.B qmail-verify
+service has a full set of control files as well as the mailboxes; the machine
+running
+.B qmail-smtpd
+still needs
+.I control/me, control/rcpthosts
+(and/or
+.I control/morercpthosts
+) to be setup.
+
+.SH LOGGING
+.B qmail-verify
+logs each decision it makes to stderr: The address followed by whether
+it's valid or not.
+
+.SH AUTHOR
+Andrew Richards, building on the work of Paul Jarc and Dan Bernstein, and with
+plenty of help along the way from Russell Nelson, John Levine and Charles Cazabon
+amongst others.
+
+.SH "SEE ALSO"
+qmail-smtpd(8).
diff --git a/qmail-verify.c b/qmail-verify.c
new file mode 100644
index 0000000..cc53e60
--- /dev/null
+++ b/qmail-verify.c
@@ -0,0 +1,487 @@
+/* qmail-verify: Based on Paul Jarc's realrcptto-2006.12.10 patch
+ *		 this separates its functionality into a separate
+ *		 program that can be invoked by an appropriately
+ *		 modified qmail-smtpd. The assumption is that
+ *		 qmail-verify will run as root or the UID that
+ *		 owns mailboxes in a SingleUID setup, whilst
+ *		 qmail-smtpd can continue to run as user qmaild.
+ *
+ *               Comments have been added to show which parts of
+ *		 qmail-1.03 various sections of code relate to.
+ *
+ *		*This program is written to be used by
+ *		 qmail-smtpd communicating with it using UDP.
+ */ 
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <limits.h>
+#include <grp.h>
+#include <pwd.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include "auto_break.h"
+#include "auto_usera.h"
+#include "auto_qmail.h"
+#include "byte.h"
+#include "case.h"
+#include "cdb.h"
+#include "constmap.h"
+#include "error.h"
+#include "fmt.h"
+#include "open.h"
+#include "str.h"
+#include "stralloc.h"
+#include "uint32.h"
+#include "substdio.h"
+#include "getln.h"
+#include "env.h"
+#include "ip.h"
+#include "qmail-verify.h"
+#include "errbits.h"
+#include "scan.h"
+
+#define enew()  { eout("qmail-verify: "); }
+#define GETPW_USERLEN 32
+#define MAXQUERYSIZE 900
+/* 900 derived as max packet size from logic in addrparse() in qmail-smtpd.c */
+
+stralloc envnoathost = {0};
+stralloc percenthack = {0};
+stralloc locals = {0};
+stralloc vdoms = {0};
+
+struct constmap mappercenthack;
+struct constmap maplocals;
+struct constmap mapvdoms;
+
+char *quser;
+
+stralloc response = {0};
+
+char *local, *dash, *extension;
+struct passwd *pw;
+
+char ppid_s[FMT_ULONG];
+char *remoteip;
+char inbuf[MAXQUERYSIZE+1]; /* +1 for trailing \0 added after receipt */
+
+void die_nomem()   { enew(); eout("Out of memory: exiting.\n"); eflush(); _exit(1); }
+void die_control() { enew(); eout("Unable to read controls: exiting.\n"); eflush(); _exit(1); }
+void die_cdb()     { enew(); eout("Unable to read cdb user database: exiting.\n"); eflush(); _exit(1); }
+void die_sys()     { enew(); eout("Unable to read system user database: exiting.\n"); eflush(); _exit(1); }
+void die_comms()   { enew(); eout("Misc. comms problem: exiting.\n"); eflush(); _exit(1); }
+void die_inuse()   { enew(); eout("Port already in use: exiting.\n"); eflush(); _exit(1); }
+void die_socket()  { enew(); eout("Error setting up socket: exiting.\n"); eflush(); _exit(1); }
+void die_privs()   { enew(); eout("Unable to drop/restore privileges: exiting.\n"); eflush(); _exit(1); }
+
+char *posstr(buf,status)
+char *buf; int status;
+{
+int pos;
+
+pos = status & QVPOSBITS;
+if (pos==QVPOS1)  str_copy(buf,"1");
+else if (pos==QVPOS2)  str_copy(buf,"2");
+ else if (pos==QVPOS3)  str_copy(buf,"3");
+  else if (pos==QVPOS4)  str_copy(buf,"4");
+   else if (pos==QVPOS5)  str_copy(buf,"5");
+    else if (pos==QVPOS6)  str_copy(buf,"6");
+     else if (pos==QVPOS7)  str_copy(buf,"7");
+      else if (pos==QVPOS8)  str_copy(buf,"8");
+       else if (pos==QVPOS9)  str_copy(buf,"9");
+        else if (pos==QVPOS10) str_copy(buf,"10");
+         else if (pos==QVPOS11) str_copy(buf,"11");
+          else if (pos==QVPOS12) str_copy(buf,"12");
+           else if (pos==QVPOS13) str_copy(buf,"13");
+            else if (pos==QVPOS14) str_copy(buf,"14");
+             else if (pos==QVPOS15) str_copy(buf,"15");
+              else str_copy(buf,"??");
+return buf;
+}
+
+char posbuf[10]; /* Large enough for anything posstr() will put in it. */
+
+int allowaddr(addr,ret)
+char *addr;
+int ret;
+{
+/*eout3("[DEBUG] Pos ",posstr(posbuf,ret),", ");*/
+/*eout3("qmail-verify: ",addr," permitted.\n");*/
+  enew(); eout4(addr," permitted for ",quser?quser:"UNKNOWN",".\n");
+  eflush();
+  return ret;
+}
+
+int denyaddr(addr,ret)
+char *addr;
+int ret;
+{
+/*eout3("[DEBUG] Pos ",posstr(posbuf,ret),", ");*/
+/*eout3("qmail-verify: ",addr," denied.\n");*/
+  enew(); eout2(addr," denied.\n");
+  eflush();
+  return ret;
+}
+
+int stat_error(path,staterror,ret)
+char* path;
+int staterror,ret;
+{
+/*eout3("[DEBUG] Pos ",posstr(posbuf,ret),", ");*/
+/*eout5("qmail-verify: Unable to stat ",path,": ",error_str(staterror),".\n");*/
+  enew(); eout5("Unable to stat ",path,": ",error_str(staterror),".\n");
+  eflush();
+  return ret;
+}
+
+int userext()	/* from qmail-getpw.c */
+{
+  char username[GETPW_USERLEN];
+  struct stat st;
+
+  extension = local + str_len(local);
+  for (;;) {
+    if (extension - local < sizeof(username))
+      if (!*extension || (*extension == *auto_break)) {
+	byte_copy(username,extension - local,local);
+	username[extension - local] = 0;
+	case_lowers(username);
+	errno = 0;
+	pw = getpwnam(username);
+	if (errno == error_txtbsy) die_sys();
+	if (pw)
+	  if (pw->pw_uid)
+	    if (stat(pw->pw_dir,&st) == 0) {
+	      if (st.st_uid == pw->pw_uid) {
+		dash = "";
+		if (*extension) { ++extension; dash = "-"; }
+		return 1;
+	      }
+	    }
+	    else
+	      if (error_temp(errno)) die_sys();
+      }
+    if (extension == local) return 0;
+    --extension;
+  }
+}
+
+static int stat_as(uid, gid, path, sbuf)
+const uid_t uid;
+const gid_t gid;
+const char * const path;
+struct stat * const sbuf;
+{
+  static gid_t groups[NGROUPS_MAX + 1];
+  int ngroups = 0;
+  const gid_t saved_egid = getegid();
+  const uid_t saved_euid = geteuid();
+  int ret = -1;
+
+  if (saved_euid == 0) {
+    ngroups = getgroups(sizeof(groups) / sizeof(groups[0]), groups);
+    if (ngroups < 0 ||
+        setgroups(1, &gid) != 0 ||
+        setegid(gid) != 0 ||
+        seteuid(uid) != 0) {
+      die_privs();
+    }
+  }
+
+  ret = stat(path, sbuf);
+
+  if (saved_euid == 0) {
+    if (seteuid(saved_euid) != 0 ||
+        setegid(saved_egid) != 0 ||
+        setgroups(ngroups, groups) != 0) {
+      die_privs();
+    }
+  }
+
+  return ret;
+}
+
+int verifyaddr(addr)
+char *addr;
+{
+  char *homedir;
+  uid_t uid = -1;
+  gid_t gid = -1;
+  /* static since they get re-used on each call to verifyaddr(). Note
+     that they don't need resetting since initial use is always with
+     stralloc_copys() except wildchars (reset with ...len=0 below). */
+  static stralloc localpart = {0};
+  static stralloc lower = {0};
+  static stralloc nughde = {0};
+  static stralloc wildchars = {0};
+  static stralloc safeext = {0};
+  static stralloc qme = {0};
+  unsigned int i,at;
+  wildchars.len=0;
+
+  /* qmail-send:rewrite */
+  if (!stralloc_copys(&localpart,addr)) die_nomem();
+  i = byte_rchr(localpart.s,localpart.len,'@');
+  if (i == localpart.len) {
+    if (!stralloc_cats(&localpart,"@")) die_nomem();
+    if (!stralloc_cat(&localpart,&envnoathost)) die_nomem();
+  }
+  while (constmap(&mappercenthack,localpart.s + i + 1,localpart.len - i - 1)) {
+    unsigned int j = byte_rchr(localpart.s,i,'%');
+    if (j == i) break;
+    localpart.len = i;
+    i = j;
+    localpart.s[i] = '@';
+  }
+  at = byte_rchr(localpart.s,localpart.len,'@');
+  if (constmap(&maplocals,localpart.s + at + 1,localpart.len - at - 1)) {
+    localpart.len = at;
+    localpart.s[at] = '\0';
+  } else {
+    unsigned int xlen,newlen;
+    char *x;
+    for (i = 0;;++i) {
+      if (i > localpart.len) return allowaddr(addr,ADDR_OK|QVPOS1);
+      if (!i || (i == at + 1) || (i == localpart.len) ||
+          ((i > at) && (localpart.s[i] == '.'))) {
+        x = constmap(&mapvdoms,localpart.s + i,localpart.len - i);
+        if (x) break;
+      }
+    }
+    if (!*x) return allowaddr(addr,ADDR_OK|QVPOS2);
+    xlen = str_len(x) + 1;  /* +1 for '-' */
+    newlen = xlen + at + 1; /* +1 for \0 */
+    if (xlen < 1 || newlen - 1 < xlen || newlen < 1 ||
+        !stralloc_ready(&localpart,newlen))
+      die_nomem();
+    localpart.s[newlen - 1] = '\0';
+    byte_copyr(localpart.s + xlen,at,localpart.s);
+    localpart.s[xlen - 1] = '-';
+    byte_copy(localpart.s,xlen - 1,x);
+    localpart.len = newlen;
+  }
+
+  /* qmail-lspawn:nughde_get */
+  {
+    /* qmail-lspawn lines 83-128 */
+    int r,fd,flagwild;
+
+    if (!stralloc_copys(&lower,"!")) die_nomem();
+    if (!stralloc_cats(&lower,localpart.s)) die_nomem();
+    if (!stralloc_0(&lower)) die_nomem();
+    case_lowerb(lower.s,lower.len);
+
+    if (!stralloc_copys(&nughde,"")) die_nomem();
+
+    fd = open_read("users/cdb");
+    if (fd == -1) {
+      if (errno != error_noent) die_cdb();
+    }
+    else
+    { /* This section parses users/cdb file */
+      uint32 dlen;
+
+      r = cdb_seek(fd,"",0,&dlen);
+      if (r != 1) die_cdb();
+      if (!stralloc_ready(&wildchars,(unsigned int) dlen)) die_nomem();
+      wildchars.len = dlen;
+      if (cdb_bread(fd,wildchars.s,wildchars.len) == -1) die_cdb();
+
+      i = lower.len;
+      flagwild = 0;
+
+      do { /* i > 0 */
+        if (!flagwild || (i == 1) ||
+            (byte_chr(wildchars.s,wildchars.len,lower.s[i - 1]) < wildchars.len))
+        {
+          r = cdb_seek(fd,lower.s,i,&dlen);
+          if (r == -1) die_cdb();
+          if (r == 1)
+          {
+            char *x;
+            unsigned long u;
+            if (!stralloc_ready(&nughde,(unsigned int) dlen)) die_nomem();
+            nughde.len = dlen;
+            if (cdb_bread(fd,nughde.s,nughde.len) == -1) die_cdb();
+            if (flagwild)
+              if (!stralloc_cats(&nughde,localpart.s + i - 1)) die_nomem();
+            if (!stralloc_0(&nughde)) die_nomem();
+            close(fd);
+            /* maybe based on qmail-lspawn lines 190-214 */
+            x=nughde.s;
+            quser=nughde.s;
+            /* skip username */
+            x += byte_chr(x,nughde.s + nughde.len - x,'\0');
+            if (x == nughde.s + nughde.len) return allowaddr(addr,ADDR_OK|QVPOS3);
+            ++x;
+            /* skip uid */
+            scan_ulong(x,&u);
+            uid = u;
+            x += byte_chr(x,nughde.s + nughde.len - x,'\0');
+            if (x == nughde.s + nughde.len) return allowaddr(addr,ADDR_OK|QVPOS4);
+            ++x;
+            /* skip gid */
+            scan_ulong(x,&u);
+            gid = u;
+            x += byte_chr(x,nughde.s + nughde.len - x,'\0');
+            if (x == nughde.s + nughde.len) return allowaddr(addr,ADDR_OK|QVPOS5);
+            ++x;
+            /* skip homedir */
+            homedir=x;
+            x += byte_chr(x,nughde.s + nughde.len - x,'\0');
+            if (x == nughde.s + nughde.len) return allowaddr(addr,ADDR_OK|QVPOS6);
+            ++x;
+            /* skip dash */
+            dash=x;
+            x += byte_chr(x,nughde.s + nughde.len - x,'\0');
+            if (x == nughde.s + nughde.len) return allowaddr(addr,ADDR_OK|QVPOS7);
+            ++x;
+            extension=x;
+            goto got_nughde;
+          }
+        }
+        /* qmail-lspawn lines 132-137 */
+        --i;
+        flagwild = 1;
+      } while (i);
+      close(fd);
+    }
+  }
+
+  /* qmail-getpw lines 61-70 */
+  local = localpart.s;
+  quser = local;
+  if (!userext()) {
+    extension = local;
+    dash = "-";
+    pw = getpwnam(auto_usera);
+    quser = auto_usera;
+  }
+  if (!pw) return denyaddr(addr,ADDR_NOK|QVPOS8);
+  if (!stralloc_copys(&nughde,pw->pw_dir)) die_nomem();
+  if (!stralloc_0(&nughde)) die_nomem();
+  homedir=nughde.s;
+  uid = pw->pw_uid;
+  gid = pw->pw_gid;
+
+  got_nughde:
+
+  /* qmail-local:qmesearch, note qmeexists() becomes stralloc_0 + stat() */
+  if (!*dash) return allowaddr(addr,ADDR_OK|QVPOS9);
+  if (!stralloc_copys(&safeext,extension)) die_nomem();
+  case_lowerb(safeext.s,safeext.len);
+  for (i = 0;i < safeext.len;++i)
+    if (safeext.s[i] == '.')
+      safeext.s[i] = ':';
+  {
+    /* qmail-local lines 383-388 */
+    struct stat st;
+    int i;
+    if (!stralloc_copys(&qme,homedir)) die_nomem();
+    if (!stralloc_cats(&qme,"/.qmail")) die_nomem();
+    if (!stralloc_cats(&qme,dash)) die_nomem();
+    if (!stralloc_cat(&qme,&safeext)) die_nomem();
+    if (!stralloc_0(&qme)) die_nomem();
+/* e.g. homedir/.qmail-localpart */
+    if (stat_as(uid,gid,qme.s,&st) == 0) return allowaddr(addr,ADDR_OK|QVPOS10);
+    if (errno != error_noent) {
+      return stat_error(qme.s,errno, STATERR|QVPOS11); /* Maybe not running as root so access denied */
+    }
+    /* qmail-local lines 398-404 */
+    for (i = safeext.len;i >= 0;--i)
+      if (!i || (safeext.s[i - 1] == '-')) {
+        if (!stralloc_copys(&qme,homedir)) die_nomem();
+        if (!stralloc_cats(&qme,"/.qmail")) die_nomem();
+        if (!stralloc_cats(&qme,dash)) die_nomem();
+        if (!stralloc_catb(&qme,safeext.s,i)) die_nomem();
+        if (!stralloc_cats(&qme,"default")) die_nomem();
+        if (!stralloc_0(&qme)) die_nomem();
+/* e.g. homedir/.qmail-[xxx-]default */
+	if (stat_as(uid,gid,qme.s,&st) == 0) return allowaddr(addr,ADDR_OK|QVPOS12);
+        if (errno != error_noent) /* Maybe not running as root so access denied */
+          return stat_error(qme.s,errno,STATERR|QVPOS13);
+      }
+    return denyaddr(addr,ADDR_NOK|QVPOS14);
+  }
+  return denyaddr(addr,ADDR_NOK|QVPOS15); /* Not sure under what conditions this line triggered, if any */
+}
+
+int main()
+{
+  int n, sock;
+  char result;
+  socklen_t clientaddrlen;
+  struct sockaddr_in sin, clientaddr;
+  unsigned long lport; /* for scan_ulong, scan_uint not in qmail src */
+  struct ip_address i;
+  char *s;
+
+  if (chdir(auto_qmail) == -1) die_control();
+  if (control_init() == -1) die_control();
+
+  if (control_rldef(&envnoathost,"control/envnoathost",1,"envnoathost") != 1)
+    die_control();
+
+  if (control_readfile(&locals,"control/locals",1) != 1) die_control();
+  if (!constmap_init(&maplocals,locals.s,locals.len,0)) die_nomem();
+  switch(control_readfile(&percenthack,"control/percenthack",0)) {
+    case -1: die_control();
+    case 0: if (!constmap_init(&mappercenthack,"",0,0)) die_nomem();
+    case 1:
+      if (!constmap_init(&mappercenthack,percenthack.s,percenthack.len,0))
+        die_nomem();
+  }
+  switch(control_readfile(&vdoms,"control/virtualdomains",0)) {
+    case -1: die_control();
+    case 0: if (!constmap_init(&mapvdoms,"",0,1)) die_nomem();
+    case 1: if (!constmap_init(&mapvdoms,vdoms.s,vdoms.len,1)) die_nomem();
+  }
+  if (!(s = env_get("LISTEN"))) s=DEFAULTQVIP;
+
+  /* Re-read control files above on SIGHUP? */
+
+  if (!(n=ip_scan(s,&i))) ip_scan(DEFAULTQVIP,&i);
+  s+=n; if ((*s==':') && scan_ulong(s+1,&lport)) ; else lport=DEFAULTQVPORT;
+
+  byte_zero(&sin, sizeof(sin));
+  sin.sin_family = AF_INET;
+  sin.sin_port = htons(lport);
+/*sin.sin_len = sizeof(sin); (optional, not defined on all systems) */
+  byte_copy(&sin.sin_addr, sizeof(i),&i);
+
+  if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) < 0) die_socket();
+  if (bind(sock, (struct sockaddr *) &sin, sizeof(sin))< 0) die_inuse();
+
+  { char tmps1[IPFMT+1], tmps2[FMT_ULONG+1];
+    tmps1[ip_fmt(tmps1,&i)]=0;
+    tmps2[fmt_ulong(tmps2,ntohs(sin.sin_port))]=0;
+    enew(); eout5("Listening on address: ",tmps1,", port ",tmps2,".\n"); eflush();
+  }
+  for (;;)
+  {
+    clientaddrlen=sizeof(clientaddr); /* Read & set by recvfrom */
+    n = recvfrom(sock,inbuf, MAXQUERYSIZE, 0, (struct sockaddr *)&clientaddr, &clientaddrlen);
+    if (n<=0) /* <0 for error, 0 for empty packet. */
+    {
+      enew(); eout("Error receiving packet.\n"); eflush();
+      continue;
+    }
+    inbuf[n]='\0'; /* Turn it into a string ('\0' terminated) */
+
+    quser = 0;
+    result=(char)verifyaddr(inbuf);
+
+    /* 'short' response packet - just the status byte - use the line below to replace 'long' version */
+    /* if (sendto(sock,&result,1,0,(struct sockaddr *)&clientaddr,sizeof(clientaddr)) < 0) die_comms(); */
+
+    /* 'long' response packet - status byte + controlling user (quser) */
+    stralloc_ready(&response, 2);
+    stralloc_copyb(&response, &result, 1);
+    if (quser) stralloc_cats(&response, quser);
+    if (response.len > QVRESPONSELEN) response.len = QVRESPONSELEN; /* Trim oversize response */
+    if (sendto(sock,response.s,response.len,0,(struct sockaddr *)&clientaddr,sizeof(clientaddr)) < 0) die_comms();
+
+  }
+}
diff --git a/qmail-verify.h b/qmail-verify.h
new file mode 100644
index 0000000..5a1b8d5
--- /dev/null
+++ b/qmail-verify.h
@@ -0,0 +1,34 @@
+#define DEFAULTQVPORT 11113
+#define DEFAULTQVIP "127.0.0.1"
+#define DEFAULTQVTIMEOUT 5
+
+#define GETPW_USERLEN 32
+/* Response length is status byte + username length */
+#define QVRESPONSELEN (1+GETPW_USERLEN)
+
+/* ADDR_NOK, ADDR_OK, ADDR_NOK_TEMP get ORed with POSx for possible debugging. */
+#define ADDR_NOK_TEMP	0x02
+#define ADDR_NOK	0x01
+#define ADDR_OK		0x00
+/* Treat a stat() error as 'valid address'; maybe not running with sufficient rights */
+#define STATERR ADDR_OK
+/* Which bits show OK / NOK: */
+#define QVRESULTBITS 0x0f
+
+#define QVPOS1	0x10
+#define QVPOS2	0x20
+#define QVPOS3	0x30
+#define QVPOS4	0x40
+#define QVPOS5	0x50
+#define QVPOS6	0x60
+#define QVPOS7	0x70
+#define QVPOS8	0x80
+#define QVPOS9	0x90
+#define QVPOS10	0xa0
+#define QVPOS11	0xb0
+#define QVPOS12	0xc0
+#define QVPOS13	0xd0
+#define QVPOS14	0xe0
+#define QVPOS15	0xf0
+/* Which bits show QVPOSx: */
+#define QVPOSBITS 0xf0
diff --git a/scan.h b/scan.h
index 53ce703..eddbaa8 100644
--- a/scan.h
+++ b/scan.h
@@ -24,4 +24,7 @@ extern unsigned int scan_memcmp();
 
 extern unsigned int scan_long();
 
+extern char *find_digit_colon_eos();
+extern int scan_ip_port();
+
 #endif
diff --git a/scan_misc.c b/scan_misc.c
new file mode 100644
index 0000000..3e20a75
--- /dev/null
+++ b/scan_misc.c
@@ -0,0 +1,39 @@
+#include "stralloc.h"
+#include "ip.h"
+#include "scan.h"
+
+/* Returns pointer to first digit or ':' in string, or end-of-string
+ * if neither found. Useful prior to scan_ip_port() if any options
+ * may precede the IP / port in the string. */
+char *find_digit_colon_eos(s)
+char *s;
+{
+  while (*s != '\0')
+  {
+    if ( *s == ':') return s;
+    if ((*s >= '0') && (*s <= '9')) return s;
+    s++;
+  }
+  return s; /* end of string '\0' */
+}
+
+/* Takes a string specifying IP address and port, separated by ':'
+ * If IP address and/or port are missing, supplied defaults are used.
+ * 0, -1 returned on success, failure respectively. */
+int scan_ip_port(s,defaultip,defaultport,ipp,portp)
+char *s, *defaultip;
+struct ip_address *ipp;
+unsigned int defaultport, *portp;
+{
+  int n;
+  char *sp;
+  unsigned long port; /* long because of scan_ulong */
+
+  if (!s) return -1; /* Can't scan a null string */
+  sp = s;
+  if (!(n=ip_scan(sp, ipp))) ip_scan(defaultip,ipp);
+  sp += n; /* n is 0 if no IP found */
+  if (!((*sp==':') && scan_ulong(sp+1,&port))) port=defaultport;
+  *portp = (unsigned int)port;
+  return 0;
+}
diff --git a/sockbits.c b/sockbits.c
new file mode 100644
index 0000000..05d1953
--- /dev/null
+++ b/sockbits.c
@@ -0,0 +1,31 @@
+#include "sockbits.h"
+#include "stralloc.h"
+#include <sys/types.h>
+#include <sys/socket.h>
+#include "error.h"
+
+int query_skt(fd,queryp,responsep,maxresponsesize,timeout,timeoutfn,errfn)
+int fd;
+stralloc *queryp;
+char *responsep;
+int maxresponsesize, timeout;
+void (*errfn)(), (*timeoutfn)();
+{
+  fd_set rfs;
+  struct timeval tv;
+  int nbytes;
+  int r=0;
+
+  if (write(fd,queryp->s,queryp->len) < 0) (*errfn)();
+  tv.tv_sec=timeout; tv.tv_usec=0;
+  FD_ZERO(&rfs); FD_SET(fd,&rfs);
+  if ((r=select(fd+1,&rfs,(fd_set *) 0,(fd_set *) 0,&tv)) <= 0) /* 0 timeout or -1 error */
+  {
+    if ((r == 0) && (errno == error_timeout)) (*timeoutfn)();
+    else (*errfn)();
+    return r; /* if timeoutfn() / errfn() doesn't _exit() */
+  }
+  nbytes = read(fd,responsep,maxresponsesize);
+  if (nbytes < 0) (*errfn)();
+  return (nbytes); /* including 0 = no output */
+}
diff --git a/sockbits.h b/sockbits.h
new file mode 100644
index 0000000..2a02749
--- /dev/null
+++ b/sockbits.h
@@ -0,0 +1 @@
+extern int query_skt();
diff --git a/udpbits.c b/udpbits.c
new file mode 100644
index 0000000..3b17f52
--- /dev/null
+++ b/udpbits.c
@@ -0,0 +1,24 @@
+#include "udpbits.h"
+#include "ip.h"
+#include "byte.h"
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+
+int connect_udp(ip,port,errfn)
+struct ip_address ip;
+unsigned int port;
+void (*errfn)();
+{
+  struct sockaddr_in sout;
+  int fd;
+
+  byte_zero(&sout,sizeof(sout));
+  sout.sin_port = htons(port);
+  sout.sin_family=AF_INET;
+  byte_copy(&sout.sin_addr,sizeof(ip),&ip);
+/*sout.sin_len = sizeof(sout); Commented out since optional & sin_len not defined on all OSes */
+  if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) (*errfn)();
+  if (connect(fd,(struct sockaddr *)&sout,sizeof(sout)) < 0) (*errfn)();
+  return fd;
+}
diff --git a/udpbits.h b/udpbits.h
new file mode 100644
index 0000000..d19e12a
--- /dev/null
+++ b/udpbits.h
@@ -0,0 +1 @@
+extern int connect_udp();
diff --git a/verifyrcpt.c b/verifyrcpt.c
new file mode 100644
index 0000000..8f737b1
--- /dev/null
+++ b/verifyrcpt.c
@@ -0,0 +1,45 @@
+#include "verifyrcpt.h"
+#include "qmail-verify.h"
+#include "ip.h"
+#include "stralloc.h"
+#include "scan.h"
+#include <sys/types.h>
+
+static int verifyrcpt_initialised=0;
+static int sockfd;
+
+int flagdenyany=0; /* Can be interrogated in qmail-smtpd.c */
+
+void verifyrcpt_init(svr,errfn) /* errfn must _exit */
+char *svr; void (*errfn)();
+{
+  struct ip_address ip;
+  unsigned int port;
+
+  if (scan_ip_port(svr,DEFAULTQVIP,DEFAULTQVPORT,&ip,&port) == -1) (*errfn)();
+  sockfd = connect_udp(ip,port,errfn);
+  verifyrcpt_initialised=1;
+}
+
+int verifyrcpt(vip,r,defer,timeoutfn,errfn)
+char *vip; stralloc *r; int defer; void (*timeoutfn)(),(*errfn)();
+{
+  char qvresponse[QVRESPONSELEN+1]; /* +1 for '\0' at end */
+  int result,n;
+
+  if (!vip) (*errfn)(); /* verifyrcpt should only be called if vip set */
+  if (!verifyrcpt_initialised) verifyrcpt_init(vip,errfn);
+
+  if (defer && flagdenyany) return ADDR_OK; /* Optional short circuit; "Controlling user" not discovered; remove this line if it's needed */
+  n = query_skt(sockfd,r,qvresponse,QVRESPONSELEN,DEFAULTQVTIMEOUT,timeoutfn,errfn);
+  if (n == 0) (*errfn)();
+  result = qvresponse[0] & QVRESULTBITS;
+  qvresponse[ ( (n > QVRESPONSELEN) ? QVRESPONSELEN : n) ] = '\0';
+    /* "Controlling user" available in qvresponse+1 for logging etc. */
+
+  if (result == ADDR_OK)
+    return ADDR_OK;
+  /* NOK: */
+  flagdenyany = 1;
+  return defer?ADDR_OK:ADDR_NOK; /* ADDR_OK if we're rejecting later */
+}
diff --git a/verifyrcpt.h b/verifyrcpt.h
new file mode 100644
index 0000000..07c48b5
--- /dev/null
+++ b/verifyrcpt.h
@@ -0,0 +1,3 @@
+extern int flagdenyany;
+void verifyrcpt_init();
+int verifyrcpt();