mailsrvr.c

							|| relay_user.rest&(FLAG('G')|FLAG('M'))) &&
						!findstr(host_name,relay_list) && 
						!findstr(host_ip,relay_list)) {
						lprintf(LOG_WARNING,"%04d !SMTP ILLEGAL RELAY ATTEMPT from %s [%s] to %s"
							,socket, reverse_path, host_ip, p);
						SAFEPRINTF(tmp,"Relay attempt to: %s", p);
						spamlog(&scfg, "SMTP", "REFUSED", tmp, host_name, host_ip, rcpt_addr, reverse_path);
						if(startup->options&MAIL_OPT_ALLOW_RELAY)
							sockprintf(socket, "553 Relaying through this server "
							"requires authentication.  "
							"Please authenticate before sending.");
						else {
							sockprintf(socket, "550 Relay not allowed.");
							stats.msgs_refused++;
						}
						break;
					}

					if(relay_user.number==0)
						SAFECOPY(relay_user.alias,"Unknown User");

					lprintf(LOG_INFO,"%04d SMTP %s relaying to external mail service: %s"
						,socket, relay_user.alias, tp+1);

					fprintf(rcptlst,"[%u]\n",rcpt_count++);
					fprintf(rcptlst,"%s=%s\n",smb_hfieldtype(RECIPIENT),rcpt_addr);
					fprintf(rcptlst,"%s=%u\n",smb_hfieldtype(RECIPIENTNETTYPE),NET_INTERNET);
					fprintf(rcptlst,"%s=%s\n",smb_hfieldtype(RECIPIENTNETADDR),p);

					sockprintf(socket,ok_rsp);
					state=SMTP_STATE_RCPT_TO;
					continue;
				}
			}
			if(tp!=NULL)
				*tp=0;	/* truncate at '@' */

			tp=strchr(p,'!');	/* Routed QWKnet mail in <qwkid!user@host> format */
			if(tp!=NULL) {
				*(tp++)=0;
				SKIP_CHAR(tp,'"');				/* Skip '"' */
				truncstr(tp,"\"");				/* Strip '"' */
				SAFECOPY(rcpt_addr,tp);
				routed=TRUE;
			}

			FIND_ALPHANUMERIC(p);				/* Skip '<' or '"' */
			truncstr(p,"\"");

			p=alias(&scfg,p,name_alias_buf);
			if(p==name_alias_buf) 
				lprintf(LOG_DEBUG,"%04d SMTP NAME ALIAS: %s (for %s)"
					,socket,p,rcpt_addr);
		
			/* Check if message is to be processed by an external mail processor */
			for(i=0;i<mailproc_count;i++) {

				if(!mailproc_list[i].process_dnsbl && dnsbl_result.s_addr)
					continue;

				if(!mailproc_list[i].process_spam && spam_bait_result)
					continue;

				if(!chk_ar(&scfg,mailproc_list[i].ar,&relay_user,&client))
					continue;

				if(findstr_in_list(p, mailproc_list[i].to) || findstr_in_list(rcpt_addr, mailproc_list[i].to)) {
					mailproc_to_match[i]=TRUE;
					break;
				}
			}
			mailproc_match=i;

			if(!strnicmp(p,"sub:",4)) {		/* Post on a sub-board */
				p+=4;
				for(i=0;i<scfg.total_subs;i++)
					if(!stricmp(p,scfg.sub[i]->code))
						break;
				if(i>=scfg.total_subs) {
					lprintf(LOG_NOTICE,"%04d !SMTP UNKNOWN SUB-BOARD: %s", socket, p);
					sockprintf(socket, "550 Unknown sub-board: %s", p);
					continue;
				}
				subnum=i;
				sockprintf(socket,ok_rsp);
				state=SMTP_STATE_RCPT_TO;
				rcpt_count++;
				continue;
			}

			/* destined for a (non-passthru) external mail processor */
			if(mailproc_match<mailproc_count) {
				fprintf(rcptlst,"[%u]\n",rcpt_count++);
				fprintf(rcptlst,"%s=%s\n",smb_hfieldtype(RECIPIENT),rcpt_addr);
#if 0	/* should we fall-through to the sysop account? */
				fprintf(rcptlst,"%s=%u\n",smb_hfieldtype(RECIPIENTEXT),1);
#endif
				lprintf(LOG_INFO,"%04d SMTP Routing mail for %s to External Mail Processor: %s"
					,socket, rcpt_addr, mailproc_list[mailproc_match].name);
				sockprintf(socket,ok_rsp);
				state=SMTP_STATE_RCPT_TO;
				continue;
			}

			usernum=0;	/* unknown user at this point */

			if(routed) {
				SAFECOPY(qwkid,p);
				truncstr(qwkid,"/");
				/* Search QWKnet hub-IDs for route destination */
				for(i=0;i<scfg.total_qhubs;i++) {
					if(!stricmp(qwkid,scfg.qhub[i]->id))
						break;
				}
				if(i<scfg.total_qhubs) {	/* found matching QWKnet Hub */

					lprintf(LOG_INFO,"%04d SMTP Routing mail for %s <%s> to QWKnet Hub: %s"
						,socket, rcpt_addr, p, scfg.qhub[i]->id);

					fprintf(rcptlst,"[%u]\n",rcpt_count++);
					fprintf(rcptlst,"%s=%s\n",smb_hfieldtype(RECIPIENT),rcpt_addr);
					fprintf(rcptlst,"%s=%u\n",smb_hfieldtype(RECIPIENTNETTYPE),NET_QWK);
					fprintf(rcptlst,"%s=%s\n",smb_hfieldtype(RECIPIENTNETADDR),p);

					sockprintf(socket,ok_rsp);
					state=SMTP_STATE_RCPT_TO;
					continue;
				}
			}

			if((p==alias_buf || p==name_alias_buf || startup->options&MAIL_OPT_ALLOW_RX_BY_NUMBER)
				&& isdigit((uchar)*p)) {
				usernum=atoi(p);			/* RX by user number */
				/* verify usernum */
				username(&scfg,usernum,str);
				if(!str[0] || !stricmp(str,"DELETED USER"))
					usernum=0;
				p=str;
			} else {
				/* RX by "user alias", "user.alias" or "user_alias" */
				usernum=smtp_matchuser(&scfg,p,startup->options&MAIL_OPT_ALLOW_SYSOP_ALIASES,FALSE);	

				if(!usernum) { /* RX by "real name", "real.name", or "sysop.alias" */
					
					/* convert "user.name" to "user name" */
					SAFECOPY(rcpt_name,p);
					for(tp=rcpt_name;*tp;tp++)	
						if(*tp=='.') *tp=' ';

					if(!stricmp(p,scfg.sys_op) || !stricmp(rcpt_name,scfg.sys_op))
						usernum=1;			/* RX by "sysop.alias" */

					if(!usernum && scfg.msg_misc&MM_REALNAME)	/* RX by "real name" */
						usernum=smtp_matchuser(&scfg, p, FALSE, TRUE);	

					if(!usernum && scfg.msg_misc&MM_REALNAME)	/* RX by "real.name" */
						usernum=smtp_matchuser(&scfg, rcpt_name, FALSE, TRUE);	
				}
			}
			if(!usernum && startup->default_user[0]) {
				usernum=matchuser(&scfg,startup->default_user,TRUE /* sysop_alias */);
				if(usernum)
					lprintf(LOG_INFO,"%04d SMTP Forwarding mail for UNKNOWN USER to default user: '%s' #%u"
						,socket,startup->default_user,usernum);
				else
					lprintf(LOG_WARNING,"%04d !SMTP UNKNOWN DEFAULT USER: '%s'"
						,socket,startup->default_user);
			}

			if(usernum==UINT_MAX) {
				lprintf(LOG_INFO,"%04d SMTP Blocked tag: %s", socket, rcpt_to);
				sockprintf(socket, "550 Unknown User: %s", rcpt_to);
				continue;
			}
			if(!usernum) {
				lprintf(LOG_WARNING,"%04d !SMTP UNKNOWN USER: '%s'", socket, rcpt_to);
				sockprintf(socket, "550 Unknown User: %s", rcpt_to);
				continue;
			}
			user.number=usernum;
			if((i=getuserdat(&scfg, &user))!=0) {
				lprintf(LOG_ERR,"%04d !SMTP ERROR %d getting data on user #%u (%s)"
					,socket, i, usernum, p);
				sockprintf(socket, "550 Unknown User: %s", rcpt_to);
				continue;
			}
			if(user.misc&(DELETED|INACTIVE)) {
				lprintf(LOG_WARNING,"%04d !SMTP DELETED or INACTIVE user #%u (%s)"
					,socket, usernum, p);
				sockprintf(socket, "550 Unknown User: %s", rcpt_to);
				continue;
			}
			if(cmd==SMTP_CMD_MAIL) {
				if((user.rest&FLAG('M')) && relay_user.number==0) {
					lprintf(LOG_NOTICE,"%04d !SMTP M-restricted user #u (%s) cannot receive unauthenticated SMTP mail"
						,socket, user.number, user.alias);
					sockprintf(socket, "550 Closed mailbox: %s", rcpt_to);
					stats.msgs_refused++;
					continue;
				}
				if(startup->max_msgs_waiting && !(user.exempt&FLAG('W')) 
					&& (waiting=getmail(&scfg, user.number, /* sent: */FALSE)) > startup->max_msgs_waiting) {
					lprintf(LOG_NOTICE,"%04d !SMTP User #%u (%s) mailbox (%u msgs) exceeds the maximum (%u) msgs waiting"
						,socket, user.number, user.alias, waiting, startup->max_msgs_waiting);
					sockprintf(socket, "450 Mailbox full: %s", rcpt_to);
					stats.msgs_refused++;
					continue;
				}
			}
			else if(cmd==SMTP_CMD_SEND) { /* Check if user online */
				for(i=0;i<scfg.sys_nodes;i++) {
					getnodedat(&scfg, i+1, &node, 0);
					if(node.status==NODE_INUSE && node.useron==user.number
						&& !(node.misc&NODE_POFF))
						break;
				}
				if(i>=scfg.sys_nodes) {
					lprintf(LOG_WARNING,"%04d !Attempt to send telegram to unavailable user #%u (%s)"
						,socket, user.number, user.alias);
					sockprintf(socket,"450 User unavailable");
					continue;
				}
			}
			if(cmd!=SMTP_CMD_MAIL)
				telegram=TRUE;

			fprintf(rcptlst,"[%u]\n",rcpt_count++);
			fprintf(rcptlst,"%s=%s\n",smb_hfieldtype(RECIPIENT),rcpt_addr);
			fprintf(rcptlst,"%s=%u\n",smb_hfieldtype(RECIPIENTEXT),user.number);

			/* Forward to Internet */
			tp=strrchr(user.netmail,'@');
			if(!telegram
				&& !routed
				&& !no_forward
				&& scfg.sys_misc&SM_FWDTONET 
				&& (user.misc&NETMAIL || forward)
				&& tp!=NULL && smb_netaddr_type(user.netmail)==NET_INTERNET 
				&& !strstr(tp,scfg.sys_inetaddr)) {
				lprintf(LOG_INFO,"%04d SMTP Forwarding to: %s"
					,socket, user.netmail);
				fprintf(rcptlst,"%s=%u\n",smb_hfieldtype(RECIPIENTNETTYPE),NET_INTERNET);
				fprintf(rcptlst,"%s=%s\n",smb_hfieldtype(RECIPIENTNETADDR),user.netmail);
				sockprintf(socket,"251 User not local; will forward to %s", user.netmail);
			} else { /* Local (no-forward) */
				if(routed) { /* QWKnet */
					fprintf(rcptlst,"%s=%u\n",smb_hfieldtype(RECIPIENTNETTYPE),NET_QWK);
					fprintf(rcptlst,"%s=%s\n",smb_hfieldtype(RECIPIENTNETADDR),user.alias);
				}						
				sockprintf(socket,ok_rsp);
			}
			state=SMTP_STATE_RCPT_TO;
			continue;
		}
		/* Message Data (header and body) */
		if(!strnicmp(buf,"DATA",4)) {
			if(state<SMTP_STATE_RCPT_TO) {
				lprintf(LOG_WARNING,"%04d !SMTP MISSING 'RCPT TO' command", socket);
				sockprintf(socket, badseq_rsp);
				continue;
			}
			if(msgtxt!=NULL) {
				fclose(msgtxt), msgtxt=NULL;
			}
			remove(msgtxt_fname);
			if((msgtxt=fopen(msgtxt_fname,"w+b"))==NULL) {
				lprintf(LOG_ERR,"%04d !SMTP ERROR %d opening %s"
					,socket, errno, msgtxt_fname);
				sockprintf(socket, insuf_stor);
				continue;
			}
			/* These vars are potentially over-written by parsing an RFC822 header */
			/* get sender_addr */
			p=strrchr(reverse_path,'<');
			if(p==NULL)	
				p=reverse_path;
			else 
				p++;
			SAFECOPY(sender_addr,p);
			truncstr(sender_addr,">");
			/* get sender */
			SAFECOPY(sender,sender_addr);
			if(truncstr(sender,"@")==NULL)
				sender[0]=0;

			sockprintf(socket, "354 send the mail data, end with <CRLF>.<CRLF>");
			if(telegram)
				state=SMTP_STATE_DATA_BODY;	/* No RFC headers in Telegrams */
			else
				state=SMTP_STATE_DATA_HEADER;
			lprintf(LOG_INFO,"%04d SMTP Receiving %s message from: %s to %s"
				,socket, telegram ? "telegram":"mail", reverse_path, rcpt_addr);
			hdr_lines=0;
			continue;
		}
		sockprintf(socket,"500 Syntax error");
		lprintf(LOG_WARNING,"%04d !SMTP UNSUPPORTED COMMAND: '%s'", socket, buf);
		if(++badcmds>9) {
			lprintf(LOG_WARNING,"%04d !TOO MANY INVALID COMMANDS (%u)",socket,badcmds);
			break;
		}
	}

	/* Free up resources here */
	smb_freemsgmem(&msg);

	if(msgtxt!=NULL)
		fclose(msgtxt);
	if(!(startup->options&MAIL_OPT_DEBUG_RX_BODY))
		remove(msgtxt_fname);
	if(rcptlst!=NULL)
		fclose(rcptlst);
	remove(rcptlst_fname);
	if(spy!=NULL)
		fclose(spy);
	js_cleanup(js_runtime, js_cx, &js_glob);

	status(STATUS_WFC);

	protected_uint32_adjust(&active_clients, -1);
	update_clients();
	client_off(socket);

	{
		int32_t remain = thread_down();
		lprintf(LOG_INFO,"%04d SMTP Session thread terminated (%u threads remain, %lu clients served)"
			,socket, remain, ++stats.smtp_served);
	}
	free(mailproc_to_match);

	/* Must be last */
	mail_close_socket(socket);
}

BOOL bounce(SOCKET sock, smb_t* smb, smbmsg_t* msg, char* err, BOOL immediate)
{
	char		str[128];
	char		attempts[64];
	int			i;
	ushort		agent=AGENT_SMTPSYSMSG;
	smbmsg_t	newmsg;

	msg->hdr.delivery_attempts++;
	lprintf(LOG_WARNING,"%04d !SEND Delivery attempt #%u FAILED (%s) for message #%lu from %s to %s"
		,sock
		,msg->hdr.delivery_attempts
		,err
		,msg->hdr.number
		,msg->from
		,msg->to_net.addr);

	if((i=smb_updatemsg(smb,msg))!=SMB_SUCCESS) {
		lprintf(LOG_ERR,"%04d !SEND BOUNCE ERROR %d (%s) incrementing delivery attempt counter"
			,sock, i, smb->last_error);
		return(FALSE);
	}

	if(!immediate && msg->hdr.delivery_attempts < startup->max_delivery_attempts)
		return(TRUE);

	newmsg=*msg;
	/* Mark original message as deleted */
	msg->hdr.attr|=MSG_DELETE;

	i=smb_updatemsg(smb,msg);
	if(msg->hdr.auxattr&MSG_FILEATTACH)
		delfattach(&scfg,msg);
	if(i!=SMB_SUCCESS) {
		lprintf(LOG_ERR,"%04d !SEND BOUNCE ERROR %d (%s) deleting message"
			,sock, i, smb->last_error);
		return(FALSE);
	}

	if(msg->from_agent==AGENT_SMTPSYSMSG	/* don't bounce 'bounce messages' */
		|| (msg->hdr.attr&MSG_NOREPLY)
		|| (msg->idx.from==0 && msg->from_net.type==NET_NONE)
		|| (msg->reverse_path!=NULL && *msg->reverse_path==0)) {
		lprintf(LOG_WARNING,"%04d !SEND Deleted undeliverable message from %s", sock, msg->from);
		return(TRUE);
	}
	
	lprintf(LOG_WARNING,"%04d !SEND Bouncing message back to %s", sock, msg->from);

	newmsg.hfield=NULL;
	newmsg.hfield_dat=NULL;
	newmsg.total_hfields=0;
	newmsg.hdr.delivery_attempts=0;

	SAFEPRINTF(str,"Delivery failure: %s",newmsg.subj);
	smb_hfield_str(&newmsg, SUBJECT, str);
	smb_hfield_str(&newmsg, RECIPIENT, newmsg.from);
	if(msg->from_agent==AGENT_PERSON) {

		if(newmsg.from_ext!=NULL) { /* Back to sender */
			smb_hfield_str(&newmsg, RECIPIENTEXT, newmsg.from_ext);
			newmsg.from_ext=NULL;	/* Clear the sender extension */
		}

		if((newmsg.from_net.type==NET_QWK || newmsg.from_net.type==NET_INTERNET)
			&& newmsg.reverse_path!=NULL) {
			smb_hfield(&newmsg, RECIPIENTNETTYPE, sizeof(newmsg.from_net.type), &newmsg.from_net.type);
			smb_hfield_str(&newmsg, RECIPIENTNETADDR, newmsg.reverse_path);
		}
	} else {
		smb_hfield(&newmsg, RECIPIENTAGENT, sizeof(msg->from_agent), &msg->from_agent);
	}
	newmsg.hdr.attr|=MSG_NOREPLY;
	strcpy(str,"Mail Delivery Subsystem");
	smb_hfield_str(&newmsg, SENDER, str);
	smb_hfield(&newmsg, SENDERAGENT, sizeof(agent), &agent);
	
	/* Put error message in subject for now */
	if(msg->hdr.delivery_attempts>1)
		SAFEPRINTF(attempts,"after %u attempts", msg->hdr.delivery_attempts);
	else
		attempts[0]=0;
	SAFEPRINTF2(str,"%s reporting delivery failure of message %s"
		,startup->host_name, attempts);
	smb_hfield_str(&newmsg, SMB_COMMENT, str);
	SAFEPRINTF2(str,"from %s to %s\r\n"
		,msg->reverse_path==NULL ? msg->from : msg->reverse_path
		,(char*)msg->to_net.addr);
	smb_hfield_str(&newmsg, SMB_COMMENT, str);
	strcpy(str,"Reason:");
	smb_hfield_str(&newmsg, SMB_COMMENT, str);
	smb_hfield_str(&newmsg, SMB_COMMENT, err);
	smb_hfield_str(&newmsg, SMB_COMMENT, "\r\nOriginal message text follows:\r\n");

	if((i=smb_addmsghdr(smb,&newmsg,SMB_SELFPACK))!=SMB_SUCCESS)
		lprintf(LOG_ERR,"%04d !BOUNCE ERROR %d (%s) adding message header"
			,sock,i,smb->last_error);
	else {
		lprintf(LOG_WARNING,"%04d !SEND Delivery failure notification (message #%ld) created for %s"
			,sock, newmsg.hdr.number, newmsg.from);
		if((i=smb_incmsg_dfields(smb,&newmsg,1))!=SMB_SUCCESS)
			lprintf(LOG_ERR,"%04d !SEND BOUNCE ERROR %d (%s) incrementing data allocation units"
				,sock, i,smb->last_error);
	}

	newmsg.dfield=NULL;				/* Don't double-free the data fields */
	newmsg.hdr.total_dfields=0;
	smb_freemsgmem(&newmsg);

	return(TRUE);
}

static int remove_msg_intransit(smb_t* smb, smbmsg_t* msg)
{
	int i;

	if((i=smb_lockmsghdr(smb,msg))!=SMB_SUCCESS) {
		lprintf(LOG_WARNING,"0000 !SEND ERROR %d (%s) locking message header #%lu"
			,i, smb->last_error, msg->idx.number);
		return(i);
	}
	msg->hdr.netattr&=~MSG_INTRANSIT;
	i=smb_putmsghdr(smb,msg);
	smb_unlockmsghdr(smb,msg);
	
	if(i!=0)
		lprintf(LOG_ERR,"0000 !SEND ERROR %d (%s) writing message header #%lu"
			,i, smb->last_error, msg->idx.number);

	return(i);
}

void get_dns_server(char* dns_server, size_t len)
{
	str_list_t	list;
	size_t		count;

	sprintf(dns_server,"%.*s",(int)len,startup->dns_server);
	if(!isalnum(dns_server[0])) {
		if((list=getNameServerList())!=NULL) {
			if((count=strListCount(list))>0) {
				sprintf(dns_server,"%.*s",(int)len,list[xp_random(count)]);
				lprintf(LOG_DEBUG,"0000 SEND using auto-detected DNS server address: %s"
					,dns_server);
			}
			freeNameServerList(list);
		}
	}
}

/* TODO: IPv6 etc. */
#ifdef __BORLANDC__
#pragma argsused
#endif
static void sendmail_thread(void* arg)
{
	int			i,j;
	char		to[128];
	char		mx[128];
	char		mx2[128];
	char		err[1024];
	char		buf[512];
	char		str[128];
	char		resp[512];
	char		toaddr[256];
	char		fromext[128];
	char		fromaddr[256];
	char		challenge[256];
	char		secret[64];
	char		md5_data[384];
	uchar		digest[MD5_DIGEST_SIZE];
	char		numeric_ip[16];
	char		domain_list[MAX_PATH+1];
	char		dns_server[16];
	char*		server;
	char*		msgtxt=NULL;
	char*		p;
	char*		tp;
	ushort		port;
	ulong		last_msg=0;
	ulong		ip_addr;
	ulong		dns;
	ulong		lines;
	ulong		bytes;
	BOOL		success;
	BOOL		first_cycle=TRUE;
	SOCKET		sock=INVALID_SOCKET;
	SOCKADDR_IN	addr;
	union xp_sockaddr	server_addr;
	char		server_ip[INET6_ADDRSTRLEN];
	time_t		last_scan=0;
	smb_t		smb;
	smbmsg_t	msg;
	mail_t*		mail;
	uint32_t	msgs;
	uint32_t	u;
	size_t		len;
	BOOL		sending_locally=FALSE;
	link_list_t	failed_server_list;

	SetThreadName("SendMail");
	thread_up(TRUE /* setuid */);

	terminate_sendmail=FALSE;

	lprintf(LOG_INFO,"0000 SendMail thread started");

	memset(&msg,0,sizeof(msg));
	memset(&smb,0,sizeof(smb));

	listInit(&failed_server_list, /* flags: */0);

	while((!terminated) && !terminate_sendmail) {

		if(startup->options&MAIL_OPT_NO_SENDMAIL) {
			sem_trywait_block(&sendmail_wakeup_sem,1000);
			continue;
		}

		if(active_sendmail!=0)
			active_sendmail=0, update_clients();

		listFreeNodes(&failed_server_list);

		smb_close(&smb);

		if(sock!=INVALID_SOCKET) {
			mail_close_socket(sock);
			sock=INVALID_SOCKET;
		}

		if(msgtxt!=NULL) {
			smb_freemsgtxt(msgtxt);
			msgtxt=NULL;
		}

		smb_freemsgmem(&msg);

		/* Don't delay on first loop */
		if(first_cycle)
			first_cycle=FALSE;
		else
			sem_trywait_block(&sendmail_wakeup_sem,startup->sem_chk_freq*1000);

		SAFEPRINTF(smb.file,"%smail",scfg.data_dir);
		smb.retry_time=scfg.smb_retry_time;
		smb.subnum=INVALID_SUB;
		if((i=smb_open(&smb))!=SMB_SUCCESS) 
			continue;
		if((i=smb_locksmbhdr(&smb))!=SMB_SUCCESS)
			continue;
		i=smb_getstatus(&smb);
		smb_unlocksmbhdr(&smb);
		if(i!=0)
			continue;
		if(smb.status.last_msg==last_msg && time(NULL)-last_scan<startup->rescan_frequency)
			continue;
		lprintf(LOG_DEBUG, "0000 SEND last_msg=%u, smb.status.last_msg=%u, elapsed=%u"
			,last_msg, smb.status.last_msg, time(NULL)-last_scan);
		last_msg=smb.status.last_msg;
		last_scan=time(NULL);
		mail=loadmail(&smb,&msgs,/* to network */0,MAIL_YOUR,0);
		for(u=0; u<msgs; u++) {
			if(active_sendmail!=0)
				active_sendmail=0, update_clients();

			if(terminated || terminate_sendmail)	/* server stopped */
				break;

			if(sock!=INVALID_SOCKET) {
				mail_close_socket(sock);
				sock=INVALID_SOCKET;
			}

			if(msgtxt!=NULL) {
				smb_freemsgtxt(msgtxt);
				msgtxt=NULL;
			}

			smb_freemsgmem(&msg);

			msg.hdr.number=mail[u].number;
			if((i=smb_getmsgidx(&smb,&msg))!=SMB_SUCCESS) {
				lprintf(LOG_ERR,"0000 !SEND ERROR %d (%s) getting message index #%lu"
					,i, smb.last_error, mail[u].number);
				break;
			}
			if((i=smb_lockmsghdr(&smb,&msg))!=SMB_SUCCESS) {
				lprintf(LOG_WARNING,"0000 !SEND ERROR %d (%s) locking message header #%lu"
					,i, smb.last_error, msg.idx.number);
				continue;
			}
			if((i=smb_getmsghdr(&smb,&msg))!=SMB_SUCCESS) {
				smb_unlockmsghdr(&smb,&msg);
				lprintf(LOG_ERR,"0000 !SEND ERROR %d (%s) reading message header #%lu"
					,i, smb.last_error, msg.idx.number);
				continue; 
			}
			if(msg.hdr.attr&MSG_DELETE || msg.to_net.type!=NET_INTERNET || msg.to_net.addr==NULL) {
				smb_unlockmsghdr(&smb,&msg);
				continue;
			}

			if(!(startup->options&MAIL_OPT_SEND_INTRANSIT) && msg.hdr.netattr&MSG_INTRANSIT) {
				smb_unlockmsghdr(&smb,&msg);
				lprintf(LOG_NOTICE,"0000 SEND Message #%lu from %s to %s - in transit"
					,msg.hdr.number, msg.from, msg.to_net.addr);
				continue;
			}
			msg.hdr.netattr|=MSG_INTRANSIT;	/* Prevent another sendmail thread from sending this msg */
			smb_putmsghdr(&smb,&msg);
			smb_unlockmsghdr(&smb,&msg);

			active_sendmail=1, update_clients();

			fromext[0]=0;
			if(msg.from_ext)
				SAFEPRINTF(fromext," #%s", msg.from_ext);
			if(msg.from_net.type==NET_INTERNET && msg.reverse_path!=NULL)
				SAFECOPY(fromaddr,msg.reverse_path);
			else 
				usermailaddr(&scfg,fromaddr,msg.from);
			truncstr(fromaddr," ");

			lprintf(LOG_INFO,"0000 SEND Message #%lu (%u of %u) from %s%s %s to %s [%s]"
				,msg.hdr.number, u+1, msgs, msg.from, fromext, fromaddr
				,msg.to, msg.to_net.addr);
			SAFEPRINTF2(str,"Sending (%u of %u)", u+1, msgs);
			status(str);
#ifdef _WIN32
			if(startup->outbound_sound[0] && !(startup->options&MAIL_OPT_MUTE)) 
				PlaySound(startup->outbound_sound, NULL, SND_ASYNC|SND_FILENAME);
#endif

			lprintf(LOG_DEBUG,"0000 SEND getting message text");
			if((msgtxt=smb_getmsgtxt(&smb,&msg,GETMSGTXT_ALL))==NULL) {
				remove_msg_intransit(&smb,&msg);
				lprintf(LOG_ERR,"0000 !SEND ERROR (%s) retrieving message text",smb.last_error);
				continue;
			}

			remove_ctrl_a(msgtxt, msgtxt);

			port=0;
			mx2[0]=0;

			sending_locally=FALSE;
			/* Check if this is a local email ToDo */
			SAFECOPY(to,(char*)msg.to_net.addr);
			truncstr(to,"> ");

			p=strrchr(to,'@');
			if(p==NULL) {
				remove_msg_intransit(&smb,&msg);
				lprintf(LOG_WARNING,"0000 !SEND INVALID destination address: %s", to);
				SAFEPRINTF(err,"Invalid destination address: %s", to);
				bounce(0, &smb,&msg,err, /* immediate: */TRUE);
				continue;
			}
			p++;
			SAFEPRINTF(domain_list,"%sdomains.cfg",scfg.ctrl_dir);
			if(stricmp(p,scfg.sys_inetaddr)==0
					|| stricmp(p,startup->host_name)==0
					|| findstr(p,domain_list)) {
				/* This is a local message... no need to send to remote */
				port = startup->smtp_port;
				/* TODO: IPv6 */
				if(startup->outgoing4.s_addr==0)
					server="127.0.0.1";
				else {
					SAFEPRINTF4(numeric_ip, "%u.%u.%u.%u"
							, startup->outgoing4.s_addr >> 24
							, (startup->outgoing4.s_addr >> 16) & 0xff
							, (startup->outgoing4.s_addr >> 8) & 0xff
							, startup->outgoing4.s_addr & 0xff);
					server = numeric_ip;
				}
				sending_locally=TRUE;
			}
			else {
				if(startup->options&MAIL_OPT_RELAY_TX) { 
					server=startup->relay_server;
					port=startup->relay_port;
				} else {
					server=p;
					tp=strrchr(p,':');	/* non-standard SMTP port */
					if(tp!=NULL) {
						*tp=0;
						port=atoi(tp+1);
					}
					if(port==0) {	/* No port specified, use MX look-up */
						get_dns_server(dns_server,sizeof(dns_server));
						if((dns=resolve_ip(dns_server))==INADDR_NONE) {
							remove_msg_intransit(&smb,&msg);
							lprintf(LOG_WARNING,"0000 !SEND INVALID DNS server address: %s"
								,dns_server);
							continue;
						}
						lprintf(LOG_DEBUG,"0000 SEND getting MX records for %s from %s",p,dns_server);
						if((i=dns_getmx(p, mx, mx2, INADDR_ANY, dns
							,startup->options&MAIL_OPT_USE_TCP_DNS ? TRUE : FALSE
							,TIMEOUT_THREAD_WAIT/2))!=0) {
							remove_msg_intransit(&smb,&msg);
							lprintf(LOG_WARNING,"0000 !SEND ERROR %d obtaining MX records for %s from %s"
								,i,p,dns_server);
							SAFEPRINTF2(err,"Error %d obtaining MX record for %s",i,p);
							bounce(0, &smb,&msg,err, /* immediate: */FALSE);
							continue;
						}
						server=mx;
					}
				}
			}
			if(!port)
				port=IPPORT_SMTP;

			if((sock=socket(AF_INET, SOCK_STREAM, IPPROTO_IP))==INVALID_SOCKET) {
				remove_msg_intransit(&smb,&msg);
				lprintf(LOG_ERR,"0000 !SEND ERROR %d opening socket", ERROR_VALUE);
				continue;
			}
			mail_open_socket(sock,"smtp|sendmail");

			if(startup->connect_timeout) {	/* Use non-blocking socket */
				long nbio=1;
				if((i=ioctlsocket(sock, FIONBIO, &nbio))!=0) {
					remove_msg_intransit(&smb,&msg);
					lprintf(LOG_ERR,"%04d !SEND ERROR %d (%d) disabling blocking on socket"
						,sock, i, ERROR_VALUE);
					continue;
				}
			}

			memset(&addr,0,sizeof(addr));
			addr.sin_addr.s_addr = htonl(startup->outgoing4.s_addr);
			addr.sin_family = AF_INET;

			i=bind(sock,(struct sockaddr *)&addr, sizeof(addr));
			if(i!=0) {
				remove_msg_intransit(&smb,&msg);
				lprintf(LOG_ERR,"%04d !SEND ERROR %d (%d) binding socket", sock, i, ERROR_VALUE);
				continue;
			}

			strcpy(err,"UNKNOWN ERROR");
			success=FALSE;
			for(j=0;j<2 && !success;j++) {
				list_node_t*	node;

				if(j) {
					if(startup->options&MAIL_OPT_RELAY_TX || !mx2[0])
						break;
					lprintf(LOG_DEBUG,"%04d SEND reverting to second MX: %s", sock, mx2);
					server=mx2;	/* Give second mx record a try */
				}
				
				lprintf(LOG_DEBUG,"%04d SEND resolving SMTP hostname: %s", sock, server);
				ip_addr=resolve_ip(server);
				if(ip_addr==INADDR_NONE) {
					SAFEPRINTF(err,"Failed to resolve SMTP hostname: %s",server);
					lprintf(LOG_WARNING,"%04d !SEND failure resolving hostname: %s", sock, server);
					continue;
				}

				memset(&server_addr,0,sizeof(server_addr));
				server_addr.in.sin_addr.s_addr = ip_addr;
				server_addr.in.sin_family = AF_INET;
				server_addr.in.sin_port = htons(port);
				inet_addrtop(&server_addr,server_ip,sizeof(server_ip));

				if((node=listFindNode(&failed_server_list,&server_addr,sizeof(server_addr))) != NULL) {
					lprintf(LOG_INFO,"%04d SEND skipping failed SMTP server: Error %d connecting to port %u on %s [%s]"
					,sock
					,node->tag
					,inet_addrport(&server_addr)
					,server,server_ip);
					SAFEPRINTF2(err,"Error %d connecting to SMTP server: %s"
						,node->tag, server);
					continue;
				}

				if((server==mx || server==mx2) 
					&& ((ip_addr&0xff)==127 || ip_addr==0)) {
					SAFEPRINTF2(err,"Bad IP address (%s) for MX server: %s"
						,server_ip,server);
					continue;
				}
				
				lprintf(LOG_INFO,"%04d SEND connecting to port %u on %s [%s]"
					,sock
					,inet_addrport(&server_addr)
					,server,server_ip);
				if((i=nonblocking_connect(sock, (struct sockaddr *)&server_addr, xp_sockaddr_len(&server_addr), startup->connect_timeout))!=0) {
					lprintf(LOG_WARNING,"%04d !SEND ERROR %d connecting to SMTP server: %s"
						,sock
						,i, server);
					SAFEPRINTF2(err,"Error %d connecting to SMTP server: %s"
						,i, server);
					listAddNodeData(&failed_server_list,&server_addr,sizeof(server_addr),i,NULL);
					continue;
				}
				success=TRUE;
			}
			if(!success) {	/* Failed to send, so bounce */
				remove_msg_intransit(&smb,&msg);
				bounce(sock, &smb,&msg,err,/* immediate: */FALSE);	
				continue;
			}

			lprintf(LOG_DEBUG,"%04d SEND connected to %s",sock,server);

			/* HELO */
			if(!sockgetrsp(sock,"220",buf,sizeof(buf))) {
				remove_msg_intransit(&smb,&msg);
				SAFEPRINTF3(err,badrsp_err,server,buf,"220");
				bounce(sock, &smb,&msg,err,/* immediate: */buf[0]=='5');
				continue;
			}
			if(startup->options&MAIL_OPT_RELAY_TX 
				&& (startup->options&MAIL_OPT_RELAY_AUTH_MASK)!=0)	/* Requires ESMTP */
				sockprintf(sock,"EHLO %s",startup->host_name);
			else
				sockprintf(sock,"HELO %s",startup->host_name);
			if(!sockgetrsp(sock,"250", buf, sizeof(buf))) {
				remove_msg_intransit(&smb,&msg);
				SAFEPRINTF3(err,badrsp_err,server,buf,"250");
				bounce(sock, &smb,&msg,err,/* immediate: */buf[0]=='5');
				continue;
			}

			/* AUTH */
			if(startup->options&MAIL_OPT_RELAY_TX 
				&& (startup->options&MAIL_OPT_RELAY_AUTH_MASK)!=0 && !sending_locally) {

				if((startup->options&MAIL_OPT_RELAY_AUTH_MASK)==MAIL_OPT_RELAY_AUTH_PLAIN) {
					/* Build the buffer: <username>\0<user-id>\0<password */
					len=safe_snprintf(buf,sizeof(buf),"%s%c%s%c%s"
						,startup->relay_user
						,0
						,startup->relay_user
						,0
						,startup->relay_pass);
					b64_encode(resp,sizeof(resp),buf,len);
					sockprintf(sock,"AUTH PLAIN %s",resp);
				} else {
					switch(startup->options&MAIL_OPT_RELAY_AUTH_MASK) {
						case MAIL_OPT_RELAY_AUTH_LOGIN:
							p="LOGIN";
							break;
						case MAIL_OPT_RELAY_AUTH_CRAM_MD5:
							p="CRAM-MD5";
							break;
						default:
							p="<unknown>";
							break;
					}
					sockprintf(sock,"AUTH %s",p);
					if(!sockgetrsp(sock,"334",buf,sizeof(buf))) {
						SAFEPRINTF3(err,badrsp_err,server,buf,"334 Username/Challenge");
						bounce(sock, &smb,&msg,err,/* immediate: */buf[0]=='5');
						continue;
					}
					switch(startup->options&MAIL_OPT_RELAY_AUTH_MASK) {
						case MAIL_OPT_RELAY_AUTH_LOGIN:
							b64_encode(p=resp,sizeof(resp),startup->relay_user,0);
							break;
						case MAIL_OPT_RELAY_AUTH_CRAM_MD5:
							p=buf;
							FIND_WHITESPACE(p);
							SKIP_WHITESPACE(p);
							b64_decode(challenge,sizeof(challenge),p,0);

							/* Calculate response */
							memset(secret,0,sizeof(secret));
							SAFECOPY(secret,startup->relay_pass);
							for(i=0;i<sizeof(secret);i++)
								md5_data[i]=secret[i]^0x36;	/* ipad */
							strcpy(md5_data+i,challenge);
							MD5_calc(digest,md5_data,sizeof(secret)+strlen(challenge));
							for(i=0;i<sizeof(secret);i++)
								md5_data[i]=secret[i]^0x5c;	/* opad */
							memcpy(md5_data+i,digest,sizeof(digest));
							MD5_calc(digest,md5_data,sizeof(secret)+sizeof(digest));
							
							safe_snprintf(buf,sizeof(buf),"%s %s",startup->relay_user,MD5_hex((BYTE*)str,digest));
							b64_encode(p=resp,sizeof(resp),buf,0);
							break;
						default:
							p="<unknown>";
							break;
					}
					sockprintf(sock,"%s",p);
					if((startup->options&MAIL_OPT_RELAY_AUTH_MASK)!=MAIL_OPT_RELAY_AUTH_CRAM_MD5) {
						if(!sockgetrsp(sock,"334",buf,sizeof(buf))) {
							SAFEPRINTF3(err,badrsp_err,server,buf,"334 Password");
							bounce(sock, &smb,&msg,err,/* immediate: */buf[0]=='5');
							continue;
						}
						switch(startup->options&MAIL_OPT_RELAY_AUTH_MASK) {
							case MAIL_OPT_RELAY_AUTH_LOGIN:
								b64_encode(p=buf,sizeof(buf),startup->relay_pass,0);
								break;
							default:
								p="<unknown>";
								break;
						}
						sockprintf(sock,"%s",p);
					}
				}
				if(!sockgetrsp(sock,"235",buf,sizeof(buf))) {
					SAFEPRINTF3(err,badrsp_err,server,buf,"235");
					bounce(sock, &smb,&msg,err,/* immediate: */buf[0]=='5');
					continue;
				}
			}

			/* MAIL */
			if(fromaddr[0]=='<')
				sockprintf(sock,"MAIL FROM: %s",fromaddr);
			else
				sockprintf(sock,"MAIL FROM: <%s>",fromaddr);
			if(!sockgetrsp(sock,"250", buf, sizeof(buf))) {
				remove_msg_intransit(&smb,&msg);
				SAFEPRINTF3(err,badrsp_err,server,buf,"250");
				bounce(sock, &smb,&msg,err,/* immediate: */buf[0]=='5');
				continue;
			}
			/* RCPT */
			if(msg.forward_path!=NULL) {
				SAFECOPY(toaddr,msg.forward_path);
			} else {
				if((p=strrchr((char*)msg.to_net.addr,'<'))!=NULL)
					p++;
				else
					p=(char*)msg.to_net.addr;
				SAFECOPY(toaddr,p);
				truncstr(toaddr,"> ");
				if((p=strrchr(toaddr,'@'))!=NULL && (tp=strrchr(toaddr,':'))!=NULL
					&& tp > p)
					*tp=0;	/* Remove ":port" designation from envelope */
			}
			sockprintf(sock,"RCPT TO: <%s>", toaddr);
			if(!sockgetrsp(sock,"25", buf, sizeof(buf))) {
				remove_msg_intransit(&smb,&msg);
				SAFEPRINTF3(err,badrsp_err,server,buf,"25*");
				bounce(sock, &smb,&msg,err,/* immediate: */buf[0]=='5');
				continue;
			}
			/* DATA */
			sockprintf(sock,"DATA");
			if(!sockgetrsp(sock,"354", buf, sizeof(buf))) {
				remove_msg_intransit(&smb,&msg);
				SAFEPRINTF3(err,badrsp_err,server,buf,"354");
				bounce(sock, &smb,&msg,err,/* immediate: */buf[0]=='5');
				continue;
			}
			bytes=strlen(msgtxt);
			lprintf(LOG_DEBUG,"%04d SEND sending message text (%u bytes) begin"
				,sock, bytes);
			lines=sockmsgtxt(sock,&msg,msgtxt,-1);
			lprintf(LOG_DEBUG,"%04d SEND send of message text (%u bytes, %u lines) complete, waiting for acknowledgement (250)"
				,sock, bytes, lines);
			if(!sockgetrsp(sock,"250", buf, sizeof(buf))) {
				/* Wait doublely-long for the acknowledgement */
				if(buf[0] || !sockgetrsp(sock,"250", buf, sizeof(buf))) {
					remove_msg_intransit(&smb,&msg);