Patrick Tracanelli <eksffa at freebsdbrasil dot com dot br>
http://www6.freebsdbrasil.com.br/~eksffa/l/dev/

This patch will make qmail-smtpd already patched with spamcontrol to do the
MAXRECIPIENTS and tarpiting tests for relay clients (split horizon), only if
RELAYMRTPCHECK env is enabled. So, it will allow this kind of selective
setup, using tcprules:

201.58.77.190:allow,RELAYCLIENT="",MAXRECIPIENTS="5",TARPITCOUNT="3",\
	TARPITDELAY="10",RELAYMRTPCHECK=""

Or globally, if RELAYMRTPCHECK exists on /var/service/smtpd/env/ for example.

Why? This way we can impose this limit to our own relayclients.

--- qmail-smtpd.c	Tue Jun  5 11:56:01 2007
+++ /tmp/qmail-smtpd.c.RELAYMRTPCHECK	Tue Jun  5 11:55:37 2007
@@ -1052,6 +1052,21 @@
     return;
   }
 
+  if (env_get("RELAYMRTPCHECK")) {
+    if (tarpitcount && flagerrcpts >= tarpitcount) {    /* Tarpitting et al. */
+      err_rcpts("Reject::RCPT::Toomany_Rcptto:",protocol.s,remoteip,remotehost,helohost.s,mailfrom.s,addr.s);
+      return;   
+    }
+    if (maxrcptcount && rcptcount > maxrcptcount) {
+      err_rcpts("Reject::RCPT::Toomany_Rcptto:",protocol.s,remoteip,remotehost,helohost.s,mailfrom.s,addr.s);
+      return;
+    }
+     if (tarpitcount && rcptcount >= tarpitcount) {
+      unsigned int rest = tarpitdelay;
+      while (rest = sleep(rest));
+    }
+  }
+
 /* this file is too long --------------------------------- Checks done; mailfrom/recipient accepted */
 
   if (!stralloc_cats(&rcptto,"T")) die_nomem();