diff -urN nrpe-2.12/include/common.h nrpe-2.12.ipv6/include/common.h
--- nrpe-2.12/include/common.h	2008-03-10 16:04:42.000000000 -0500
+++ nrpe-2.12.ipv6/include/common.h	2010-12-28 09:41:12.000000000 -0600
@@ -45,6 +45,7 @@
 #define MAX_FILENAME_LENGTH     256
 
 #define MAX_HOST_ADDRESS_LENGTH	256	/* max size of a host address */
+#define MAX_IP_SIZE		128	/* max size of an ip address */
 
 #define NRPE_HELLO_COMMAND      "_NRPE_CHECK"
 
diff -urN nrpe-2.12/src/nrpe.c nrpe-2.12.ipv6/src/nrpe.c
--- nrpe-2.12/src/nrpe.c	2008-03-10 16:04:43.000000000 -0500
+++ nrpe-2.12.ipv6/src/nrpe.c	2010-12-23 12:33:35.000000000 -0600
@@ -50,7 +50,7 @@
 char    config_file[MAX_INPUT_BUFFER]="nrpe.cfg";
 int     log_facility=LOG_DAEMON;
 int     server_port=DEFAULT_SERVER_PORT;
-char    server_address[16]="0.0.0.0";
+char    server_address[40]="::";
 int     socket_timeout=DEFAULT_SOCKET_TIMEOUT;
 int     command_timeout=DEFAULT_COMMAND_TIMEOUT;
 int     connection_timeout=DEFAULT_CONNECTION_TIMEOUT;
@@ -694,8 +694,8 @@
 
 /* wait for incoming connection requests */
 void wait_for_connections(void){
-	struct sockaddr_in myname;
-	struct sockaddr_in *nptr;
+	struct sockaddr_in6 myname;
+	struct sockaddr_in6 *nptr;
 	struct sockaddr addr;
 	int rc;
 	int sock, new_sd;
@@ -710,7 +710,7 @@
 #endif
 
 	/* create a socket for listening */
-	sock=socket(AF_INET,SOCK_STREAM,0);
+	sock=socket(AF_INET6,SOCK_STREAM,0);
 
 	/* exit if we couldn't create the socket */
 	if(sock<0){
@@ -728,15 +728,14 @@
 		exit(STATE_UNKNOWN);
 	        }
 
-	myname.sin_family=AF_INET;
-	myname.sin_port=htons(server_port);
- 	bzero(&myname.sin_zero,8);
+	myname.sin6_family=AF_INET6;
+	myname.sin6_port=htons(server_port);
 
 	/* what address should we bind to? */
         if(!strlen(server_address))
-		myname.sin_addr.s_addr=INADDR_ANY;
+		myname.sin6_addr=in6addr_any;
 
-	else if(!my_inet_aton(server_address,&myname.sin_addr)){
+	else if(!inet_pton(AF_INET6,server_address,&myname.sin6_addr)){
 		syslog(LOG_ERR,"Server address is not a valid IP address\n");
 		exit(STATE_CRITICAL);
                 }
@@ -759,7 +758,7 @@
 		syslog(LOG_NOTICE,"Warning: Daemon is configured to accept command arguments from clients!");
 #endif
 
-	syslog(LOG_INFO,"Listening for connections on port %d\n",htons(myname.sin_port));
+	syslog(LOG_INFO,"Listening for connections on port %d\n",htons(myname.sin6_port));
 
 	if(allowed_hosts)
 		syslog(LOG_INFO,"Allowing connections from: %s\n",allowed_hosts);
@@ -862,23 +861,26 @@
 					return;
 		                        }
 
-				nptr=(struct sockaddr_in *)&addr;
+				nptr=(struct sockaddr_in6 *)&addr;
+
+				char nptr_host[MAX_IP_SIZE];
+				inet_ntop(AF_INET6, &nptr->sin6_addr, nptr_host, MAX_IP_SIZE);
 
 				/* log info to syslog facility */
 				if(debug==TRUE)
-					syslog(LOG_DEBUG,"Connection from %s port %d",inet_ntoa(nptr->sin_addr),nptr->sin_port);
+					syslog(LOG_DEBUG,"Connection from %s port %d",nptr_host,nptr->sin6_port);
 
                                 /* is this is a blessed machine? */
 				if(allowed_hosts){
 
-					if(!is_an_allowed_host(inet_ntoa(nptr->sin_addr))){
+					if(!is_an_allowed_host(nptr_host)){
 
                                                /* log error to syslog facility */
-                                               syslog(LOG_ERR,"Host %s is not allowed to talk to us!",inet_ntoa(nptr->sin_addr));
+                                               syslog(LOG_ERR,"Host %s is not allowed to talk to us!", nptr_host);
 
                                                /* log info to syslog facility */
 					       if(debug==TRUE)
-						       syslog(LOG_DEBUG,"Connection from %s closed.",inet_ntoa(nptr->sin_addr));
+						       syslog(LOG_DEBUG,"Connection from %s closed.", nptr_host);
 
 					       /* close socket prior to exiting */
                                                close(new_sd);
@@ -918,7 +920,7 @@
 
 				/* log info to syslog facility */
 				if(debug==TRUE)
-					syslog(LOG_DEBUG,"Connection from %s closed.",inet_ntoa(nptr->sin_addr));
+					syslog(LOG_DEBUG,"Connection from %s closed.", nptr_host);
 
 				/* close socket prior to exiting */
 				close(new_sd);
@@ -987,13 +989,15 @@
 		save_connecting_host=strdup(connecting_host);
 		for(temp_ptr=strtok(temp_buffer,",");temp_ptr!=NULL;temp_ptr=strtok(NULL,",")){
 
-			myhost=gethostbyname(temp_ptr);
+			myhost=gethostbyname2(temp_ptr, AF_INET6);
 			if(myhost!=NULL){
 
 				/* check all addresses for the host... */
 				for(pptr=myhost->h_addr_list;*pptr!=NULL;pptr++){
 					memcpy(&addr, *pptr, sizeof(addr));
-					if(!strcmp(save_connecting_host, inet_ntoa(addr))){
+					char addr_p[MAX_IP_SIZE];
+					inet_ntop(AF_INET6, &addr, addr_p, MAX_IP_SIZE);
+					if(!strcmp(save_connecting_host, addr_p)){
 						result=1;
 						break;
 					        }