diff --git a/src/fieldset.c b/src/fieldset.c
index 5c105cb..25752fa 100644
--- a/src/fieldset.c
+++ b/src/fieldset.c
@@ -7,31 +7,14 @@
 
 #include "../lib/logger.h"
 
-int fs_split_string(char* in, int *len, char**results)
+void gen_fielddef_set(fielddefset_t *fds, fieldset_t fs[], int len)
 {
-	
-	char** fields = calloc(MAX_FIELDS, sizeof(char*));
-	memset(fields, 0, sizeof(fields));
-	int retvlen = 0;
-	char *currloc = in;
-	// parse csv into a set of strings
-	while (1) {
-		size_t len = strcspn(currloc, ", ");	
-		char *new = malloc(len+1);
-			
-	
+	if (fds->len + len > MAX_FIELDS) {
+		log_fatal("fieldset", "out of room in field def set");
 	}
-
-	(void)len;
-	*results = fields;
-	*len = retvlen;
-	(void)results;
-	return 0;
-}
-
-void combine_definitions()
-{
-
+	fielddef_t *open = &(fds->fielddefs[fds->len]);
+	memcpy(open, fs, len*sizeof(fielddef_t)); 
+	fds->len += len;
 }
 
 fieldset_t *fs_new_fieldset(void)
@@ -75,8 +58,27 @@ void fs_add_binary(fieldset_t *fs, const char *name, size_t len,
 	fs_add_word(fs, name, FS_BINARY, free_, len, value);
 }
 
-void fs_free(fieldset_t *fs)
+uint64_t fs_get_uint64_by_index(fieldset_t *fs, int index)
 {
+	return (uint64_t) fs->fields[i].value;
+}
+
+char* fs_get_string_by_index(fieldset_t *fs, int index)
+{
+	return (char*) fs->fields[i].value;
+}
+
+int fds_get_index_by_name(fielddefset_t *fds, char *name)
+{
+	for (int i=0; i < fds->len; i++) {
+		if (!strcmp(fds->fielddefs[i].name, name)) {
+			return i;
+		}
+	}
+	return -1;
+}
+
+void fs_free(fieldset_t *fs)
 	for (int i=0; i < fs->len; i++) {
 		field_t *f = &(fs->fields[i]);
 		if (f->free_) {
diff --git a/src/fieldset.h b/src/fieldset.h
index 5c47990..d733dee 100644
--- a/src/fieldset.h
+++ b/src/fieldset.h
@@ -8,6 +8,7 @@
 
 #include <stdlib.h>
 #include <stdint.h>
+#include "types.h"
 
 #ifndef _FIELDSET_H
 #define _FIELDSET_H
@@ -29,6 +30,11 @@ typedef struct field_def {
 	const char *desc;
 } fielddef_t;
 
+typedef struct fielddef_set {
+	fielddef_t fielddefs[MAX_FIELDS];
+	int len;
+} fielddefset_t;
+
 // the internal field type used by fieldset
 typedef struct field {
 	const char *name;
@@ -61,6 +67,14 @@ typedef struct translation {
 
 fieldset_t *fs_new_fieldset(void);
 
+uint64_t fs_get_uint64_by_index(fieldset_t *fs, int index);
+
+char* fs_get_string_by_index(fieldset_t *fs, int index);
+
+int fds_get_index_by_name(fielddefset_t *fds, char *name);
+
+void gen_fielddef_set(fielddefset_t *fds, fieldset_t fs[], int len);
+
 void fs_add_uint64(fieldset_t *fs, const char *name, uint64_t value);
 
 void fs_add_string(fieldset_t *fs, const char *name, char *value, int free_);
diff --git a/src/probe_modules/module_icmp_echo.c b/src/probe_modules/module_icmp_echo.c
index 50907ad..cb6e9a4 100644
--- a/src/probe_modules/module_icmp_echo.c
+++ b/src/probe_modules/module_icmp_echo.c
@@ -82,33 +82,8 @@ void icmp_echo_print_packet(FILE *fp, void* packet)
 			ntohs(icmp_header->icmp_cksum),
 			ntohs(icmp_header->icmp_id),
 			ntohs(icmp_header->icmp_seq));
-	struct in_addr *s = (struct in_addr *) &(iph->saddr);
-	struct in_addr *d = (struct in_addr *) &(iph->daddr);
-	char srcip[20];
-	char dstip[20];
-	// inet_ntoa is a const char * so we if just call it in
-	// fprintf, you'll get back wrong results since we're
-	// calling it twice.
-	strncpy(srcip, inet_ntoa(*s), 19);
-	strncpy(dstip, inet_ntoa(*d), 19);
-	fprintf(fp, "ip { saddr: %s | daddr: %s | checksum: %u }\n",
-			srcip,
-			dstip,
-			ntohl(iph->check));
-	fprintf(fp, "eth { shost: %02x:%02x:%02x:%02x:%02x:%02x | "
-			"dhost: %02x:%02x:%02x:%02x:%02x:%02x }\n",
-			(int) ((unsigned char *) ethh->h_source)[0],
-			(int) ((unsigned char *) ethh->h_source)[1],
-			(int) ((unsigned char *) ethh->h_source)[2],
-			(int) ((unsigned char *) ethh->h_source)[3],
-			(int) ((unsigned char *) ethh->h_source)[4],
-			(int) ((unsigned char *) ethh->h_source)[5],
-			(int) ((unsigned char *) ethh->h_dest)[0],
-			(int) ((unsigned char *) ethh->h_dest)[1],
-			(int) ((unsigned char *) ethh->h_dest)[2],
-			(int) ((unsigned char *) ethh->h_dest)[3],
-			(int) ((unsigned char *) ethh->h_dest)[4],
-			(int) ((unsigned char *) ethh->h_dest)[5]);
+	fprintf_ip_header(fp, iph);
+	fprintf_eth_header(fp, ethh);
 	fprintf(fp, "------------------------------------------------------\n");
 }
 
diff --git a/src/probe_modules/module_tcp_synscan.c b/src/probe_modules/module_tcp_synscan.c
index 448a678..a8f2e23 100644
--- a/src/probe_modules/module_tcp_synscan.c
+++ b/src/probe_modules/module_tcp_synscan.c
@@ -84,45 +84,18 @@ void synscan_print_packet(FILE *fp, void* packet)
 			ntohs(tcph->dest),
 			ntohl(tcph->seq),
 			ntohl(tcph->check));
-	struct in_addr *s = (struct in_addr *) &(iph->saddr);
-	struct in_addr *d = (struct in_addr *) &(iph->daddr);
-	char srcip[20];
-	char dstip[20];
-	// inet_ntoa is a const char * so we if just call it in
-	// fprintf, you'll get back wrong results since we're
-	// calling it twice.
-	strncpy(srcip, inet_ntoa(*s), 19);
-	strncpy(dstip, inet_ntoa(*d), 19);
-	fprintf(fp, "ip { saddr: %s | daddr: %s | checksum: %u }\n",
-			srcip,
-			dstip,
-			ntohl(iph->check));
-	fprintf(fp, "eth { shost: %02x:%02x:%02x:%02x:%02x:%02x | "
-			"dhost: %02x:%02x:%02x:%02x:%02x:%02x }\n",
-			(int) ((unsigned char *) ethh->h_source)[0],
-			(int) ((unsigned char *) ethh->h_source)[1],
-			(int) ((unsigned char *) ethh->h_source)[2],
-			(int) ((unsigned char *) ethh->h_source)[3],
-			(int) ((unsigned char *) ethh->h_source)[4],
-			(int) ((unsigned char *) ethh->h_source)[5],
-			(int) ((unsigned char *) ethh->h_dest)[0],
-			(int) ((unsigned char *) ethh->h_dest)[1],
-			(int) ((unsigned char *) ethh->h_dest)[2],
-			(int) ((unsigned char *) ethh->h_dest)[3],
-			(int) ((unsigned char *) ethh->h_dest)[4],
-			(int) ((unsigned char *) ethh->h_dest)[5]);
+	fprintf_ip_header(fp, iph);
+	fprintf_eth_header(fp, ethh);
 	fprintf(fp, "------------------------------------------------------\n");
 }
 
-
-
 int synscan_validate_packet(const struct iphdr *ip_hdr, uint32_t len, 
-				__attribute__((unused))uint32_t *src_ip, uint32_t *validation)
+		__attribute__((unused))uint32_t *src_ip, 
+		uint32_t *validation)
 {
 	if (ip_hdr->protocol != IPPROTO_TCP) {
 		return 0;
 	}
-
 	if ((4*ip_hdr->ihl + sizeof(struct tcphdr)) > len) {
 		// buffer not large enough to contain expected tcp header 
 		return 0;
@@ -130,27 +103,21 @@ int synscan_validate_packet(const struct iphdr *ip_hdr, uint32_t len,
 	struct tcphdr *tcp = (struct tcphdr*)((char *)ip_hdr + 4*ip_hdr->ihl);
 	uint16_t sport = tcp->source;
 	uint16_t dport = tcp->dest;
-
 	// validate source port
 	if (ntohs(sport) != zconf.target_port) {
 		return 0;
 	}
-
 	// validate destination port
 	if (!check_dst_port(ntohs(dport), num_ports, validation)) {
 		return 0;
 	}
-
 	// validate tcp acknowledgement number
 	if (htonl(tcp->ack_seq) != htonl(validation[0])+1) {
 		return 0;
 	}
-	
 	return 1;
 }
 
-
-
 void synscan_process_packet(const u_char *packet,
 		__attribute__((unused)) uint32_t len, fieldset_t *fs)
 {
@@ -174,13 +141,18 @@ void synscan_process_packet(const u_char *packet,
 }
 
 static fielddef_t fields[] = {
-	{.name = "sport", .type = "int", .desc = "TCP source port"},
-	{.name = "dport", .type = "int", .desc = "TCP destination port"},
+	{.name = "sport",  .type = "int", .desc = "TCP source port"},
+	{.name = "dport",  .type = "int", .desc = "TCP destination port"},
 	{.name = "seqnum", .type = "int", .desc = "TCP sequence number"},
 	{.name = "acknum", .type = "int", .desc = "TCP acknowledgement number"},
 	{.name = "window", .type = "int", .desc = "TCP window"},
 };
 
+const char *help =
+		"Probe module that sends a TCP SYN packet to a specific "
+		"port. Possible classifications are: synack and rst. A "
+		"SYN-ACK packet is considered a success and a reset packet "
+		"is considered a failed response.";
 
 probe_module_t module_tcp_synscan = {
 	.name = "tcp_synscan",
@@ -195,5 +167,6 @@ probe_module_t module_tcp_synscan = {
 	.process_packet = &synscan_process_packet,
 	.validate_packet = &synscan_validate_packet,
 	.close = NULL,
+	.helptext = help,
 	.fields = fields};
 
diff --git a/src/probe_modules/module_udp.c b/src/probe_modules/module_udp.c
index be02adb..e048b64 100644
--- a/src/probe_modules/module_udp.c
+++ b/src/probe_modules/module_udp.c
@@ -109,14 +109,17 @@ int udp_global_initialize(struct state_conf *conf) {
 			udp_send_msg[i] = (n & 0xff);
 		}
 	} else {
-		log_fatal("udp", "unknown UDP probe specification (expected file:/path, text:STRING, or hex:01020304)");
+		log_fatal("udp", "unknown UDP probe specification "
+				 "(expected file:/path, text:STRING, "
+				 "or hex:01020304)");
 		free(udp_send_msg);
 		free(args);
 		exit(1);
 	}
 
 	if (udp_send_msg_len > MAX_UDP_PAYLOAD_LEN) {
-		log_warn("udp", "warning: reducing UDP payload to %d bytes (from %d) to fit on the wire\n", 
+		log_warn("udp", "warning: reducing UDP payload to %d "
+			        "bytes (from %d) to fit on the wire\n", 
 				MAX_UDP_PAYLOAD_LEN, udp_send_msg_len);
 		udp_send_msg_len = MAX_UDP_PAYLOAD_LEN;
 	}
@@ -132,7 +135,6 @@ int udp_global_cleanup(__attribute__((unused)) struct state_conf *zconf,
 	return(0);
 }
 
-
 int udp_init_perthread(void* buf, macaddr_t *src,
 		macaddr_t *gw, __attribute__((unused)) port_h_t dst_port)
 {
@@ -158,9 +160,6 @@ int udp_init_perthread(void* buf, macaddr_t *src,
 	return EXIT_SUCCESS;
 }
 
-
-
-
 int udp_make_packet(void *buf, ipaddr_n_t src_ip, ipaddr_n_t dst_ip, 
 		uint32_t *validation, int probe_num)
 {
@@ -188,34 +187,8 @@ void udp_print_packet(FILE *fp, void* packet)
 			ntohs(udph->source),
 			ntohs(udph->dest),
 			ntohl(udph->check));
-	//ip_header = (struct iphdr*)(&eth_header[1])
-	struct in_addr *s = (struct in_addr *) &(iph->saddr);
-	struct in_addr *d = (struct in_addr *) &(iph->daddr);
-	char srcip[20];
-	char dstip[20];
-	// inet_ntoa is a const char * so we if just call it in
-	// fprintf, you'll get back wrong results since we're
-	// calling it twice.
-	strncpy(srcip, inet_ntoa(*s), 19);
-	strncpy(dstip, inet_ntoa(*d), 19);
-	fprintf(fp, "ip { saddr: %s | daddr: %s | checksum: %u }\n",
-			srcip,
-			dstip,
-			ntohl(iph->check));
-	fprintf(fp, "eth { shost: %02x:%02x:%02x:%02x:%02x:%02x | "
-			"dhost: %02x:%02x:%02x:%02x:%02x:%02x }\n",
-			(int) ((unsigned char *) ethh->h_source)[0],
-			(int) ((unsigned char *) ethh->h_source)[1],
-			(int) ((unsigned char *) ethh->h_source)[2],
-			(int) ((unsigned char *) ethh->h_source)[3],
-			(int) ((unsigned char *) ethh->h_source)[4],
-			(int) ((unsigned char *) ethh->h_source)[5],
-			(int) ((unsigned char *) ethh->h_dest)[0],
-			(int) ((unsigned char *) ethh->h_dest)[1],
-			(int) ((unsigned char *) ethh->h_dest)[2],
-			(int) ((unsigned char *) ethh->h_dest)[3],
-			(int) ((unsigned char *) ethh->h_dest)[4],
-			(int) ((unsigned char *) ethh->h_dest)[5]);
+	fprintf_ip_header(fp, iph);
+	fprintf_eth_header(fp, ethh);
 	fprintf(fp, "------------------------------------------------------\n");
 }
 
diff --git a/src/probe_modules/packet.c b/src/probe_modules/packet.c
index 7e2ee42..0ff752a 100644
--- a/src/probe_modules/packet.c
+++ b/src/probe_modules/packet.c
@@ -6,7 +6,6 @@
  * of the License at http://www.apache.org/licenses/LICENSE-2.0
  */
 
-
 #include "packet.h"
 
 #include <stdlib.h>
@@ -36,6 +35,41 @@ void print_macaddr(struct ifreq* i)
 			(int) ((unsigned char *) &i->ifr_hwaddr.sa_data)[5]);
 }
 
+void fprintf_ip_header(FILE *fp, struct iphdr *iph)
+{
+	struct in_addr *s = (struct in_addr *) &(iph->saddr);
+	struct in_addr *d = (struct in_addr *) &(iph->daddr);
+	char srcip[20];
+	char dstip[20];
+	// inet_ntoa is a const char * so we if just call it in
+	// fprintf, you'll get back wrong results since we're
+	// calling it twice.
+	strncpy(srcip, inet_ntoa(*s), 19);
+	strncpy(dstip, inet_ntoa(*d), 19);
+	fprintf(fp, "ip { saddr: %s | daddr: %s | checksum: %u }\n",
+			srcip,
+			dstip,
+			ntohl(iph->check));
+}
+
+void fprintf_eth_header(FILE *fp, struct ethhdr *ethh)
+{
+	fprintf(fp, "eth { shost: %02x:%02x:%02x:%02x:%02x:%02x | "
+			"dhost: %02x:%02x:%02x:%02x:%02x:%02x }\n",
+			(int) ((unsigned char *) ethh->h_source)[0],
+			(int) ((unsigned char *) ethh->h_source)[1],
+			(int) ((unsigned char *) ethh->h_source)[2],
+			(int) ((unsigned char *) ethh->h_source)[3],
+			(int) ((unsigned char *) ethh->h_source)[4],
+			(int) ((unsigned char *) ethh->h_source)[5],
+			(int) ((unsigned char *) ethh->h_dest)[0],
+			(int) ((unsigned char *) ethh->h_dest)[1],
+			(int) ((unsigned char *) ethh->h_dest)[2],
+			(int) ((unsigned char *) ethh->h_dest)[3],
+			(int) ((unsigned char *) ethh->h_dest)[4],
+			(int) ((unsigned char *) ethh->h_dest)[5]);
+}
+
 void make_eth_header(struct ethhdr *ethh, macaddr_t *src, macaddr_t *dst)
 {
 	memcpy(ethh->h_source, src, ETH_ALEN);
diff --git a/src/probe_modules/probe_modules.c b/src/probe_modules/probe_modules.c
index f87ebeb..27a3238 100644
--- a/src/probe_modules/probe_modules.c
+++ b/src/probe_modules/probe_modules.c
@@ -31,7 +31,6 @@ probe_module_t* probe_modules[] = {
 	// ADD YOUR MODULE HERE
 };
 
-
 probe_module_t* get_probe_module_by_name(const char* name)
 {
 	for (int i=0; i < (int) (sizeof(probe_modules)/sizeof(probe_modules[0])); i++) {
@@ -76,6 +75,8 @@ fielddef_t ip_fields[] = {
 
 fielddef_t sys_fields[] = {
 	{.name="repeat", .type="int", .desc="Is response a repeat response from host"},
+	{.name="cooldown", .type="int", .desc="Was response received during the cooldown period"},
+
 	{.name="timestamp-str", .type="string", .desc="timestamp of when response arrived in ISO8601 format."}
 }
 
@@ -87,9 +88,8 @@ void fs_add_ip_fields(fieldset_t *fs, struct iphdr *ip)
 	fs_add_uint64(fs, "ttl", ntohl(ip->ttl));
 }
 
-void fs_add_system_fields(fieldset_t *fs)
+void fs_add_system_fields(fieldset_t *fs, int is_repeat, int in_cooldown)
 {
 
-
 }
 
diff --git a/src/probe_modules/probe_modules.h b/src/probe_modules/probe_modules.h
index 613c1e2..b077af7 100644
--- a/src/probe_modules/probe_modules.h
+++ b/src/probe_modules/probe_modules.h
@@ -37,12 +37,14 @@ typedef struct probe_module {
 	probe_classify_packet_cb process_packet;
 	probe_close_cb close;
 	fielddef_t *fields;
-
+	const char *helptext;
 
 } probe_module_t;
 
 probe_module_t* get_probe_module_by_name(const char*);
 
+void fs_add_ip_fields(fieldset_t *fs, struct iphdr *ip);
+void fs_add_system_fields(fieldset_t *fs, int is_repeat, int in_cooldown);
 void print_probe_modules(void);
 
 #endif // HEADER_PROBE_MODULES_H
diff --git a/src/recv.c b/src/recv.c
index 1afa9ee..76370cd 100644
--- a/src/recv.c
+++ b/src/recv.c
@@ -27,11 +27,13 @@
 #include <sys/socket.h>
 #include <sys/ioctl.h>
 #include <net/if.h>
+#include <assert.h>
 
 #include "../lib/logger.h"
 
 #include "state.h"
 #include "validate.h"
+#include "fieldset.h"
 #include "probe_modules/probe_modules.h"
 #include "output_modules/output_modules.h"
 
@@ -92,9 +94,16 @@ void packet_cb(u_char __attribute__((__unused__)) *user,
 	}
 
 	int is_repeat = check_ip(src_ip);
-	response_type_t *r = zconf.probe_module->classify_packet(bytes, buflen);
 
-	if (r->is_success) {
+	fieldset_t *fs = fs_new_fieldset();
+	fs_add_ip_fields(fs, ip_hdr);
+	zconf.probe_module->process_packet(bytes, buflen, fs);
+	fs_add_system_fields(fs, is_repeat, zsend.complete);
+	int success_index = zconf.fsconf.success_index;
+	assert(success_index < fs->len);
+	int is_success = fs_get_uint64_byindex(success_index);
+	
+	if (is_success) {
 		zrecv.success_total++;
 		if (!is_repeat) {
 			zrecv.success_unique++;
@@ -106,19 +115,15 @@ void packet_cb(u_char __attribute__((__unused__)) *user,
 				zrecv.cooldown_unique++;
 			}
 		}
-		if (zconf.output_module && zconf.output_module->success_ip) {
-			zconf.output_module->success_ip(
-					ip_hdr->saddr, ip_hdr->daddr,
-					r->name, is_repeat, zsend.complete, bytes, buflen);
-		}
+		
 	} else {
 		zrecv.failure_total++;
-		if (zconf.output_module && zconf.output_module->other_ip) {
-			zconf.output_module->other_ip(
-					ip_hdr->saddr, ip_hdr->daddr,
-					r->name, is_repeat,	zsend.complete, bytes, buflen);
-		}
 	}
+	//if (zconf.output_module && zconf.output_module->process_record) {
+	//	//zconf.output_module->success_ip(
+	//	//		ip_hdr->saddr, ip_hdr->daddr,
+	//	//		r->name, is_repeat, zsend.complete, bytes, buflen);
+	//}
 
 	if (zconf.output_module && zconf.output_module->update
 			&& !(zrecv.success_unique % zconf.output_module->update_interval)) {
diff --git a/src/state.h b/src/state.h
index 7730b99..efba852 100644
--- a/src/state.h
+++ b/src/state.h
@@ -13,20 +13,26 @@
 #include <netinet/ether.h>
 #include <net/if.h>
 
+#include "types.h"
+#include "fieldset.h"
+
 #ifndef _STATE_H
 #define _STATE_H
 
 #define MAX_PACKET_SIZE 4096
 
-typedef uint32_t ipaddr_n_t; // IPv4 address network order
-typedef uint32_t ipaddr_h_t; // IPv4 address host order
-typedef uint16_t port_n_t; // port network order
-typedef uint16_t port_h_t; // port host order
-typedef unsigned char macaddr_t;
-
 struct probe_module;
 struct output_module;
 
+struct fieldset_conf {
+	fielddefset_t defs;
+	int *translation;
+	int translation_len;
+	int success_index;
+	int classification_index;
+};
+
+
 // global configuration
 struct state_conf {
 	int log_level;
@@ -73,6 +79,7 @@ struct state_conf {
 	char *whitelist_filename;
 	char *raw_output_fields;
 	char **output_fields;
+	struct fieldset_conf fs_conf;
 	int output_fields_len;
 	int dryrun;
 	int summary;
@@ -81,6 +88,7 @@ struct state_conf {
 };
 extern struct state_conf zconf;
 
+
 // global sender stats
 struct state_send {
 	double start;
diff --git a/src/zmap.c b/src/zmap.c
index 79a0f7c..3766d33 100644
--- a/src/zmap.c
+++ b/src/zmap.c
@@ -367,6 +367,59 @@ int main(int argc, char *argv[])
 	if (cmdline_parser_required(&args, CMDLINE_PARSER_PACKAGE) != 0) {
 		exit(EXIT_FAILURE);
 	}
+	// parse the provided probe and output module s.t. that we can support
+	// other command-line helpers (e.g. probe help)
+	zconf.output_module = get_output_module_by_name(args.output_module_arg);
+	if (!zconf.output_module) {
+	  fprintf(stderr, "%s: specified output module (%s) does not exist\n",
+		  CMDLINE_PARSER_PACKAGE, args.output_module_arg);
+	  exit(EXIT_FAILURE);
+	}
+	zconf.probe_module = get_probe_module_by_name(args.probe_module_arg);
+	if (!zconf.probe_module) {
+		fprintf(stderr, "%s: specified probe module (%s) does not exist\n",
+				CMDLINE_PARSER_PACKAGE, args.probe_module_arg);
+	  exit(EXIT_FAILURE);
+	}
+
+	// now that we know the probe module, let's find what it supports
+	memset(zconf.fs_conf, 0, sizeof(struct fieldset_conf));
+	// the set of fields made available to a user is constructed
+	// of IP header fields + probe module fields + system fields
+	fielddefset_t *fds = &(zconf.fs_conf.defs);
+	gen_fieldset_def(fds, &(ip_fields),
+		sizeof(ip_fields)/sizeof(fielddef_t));
+	gen_fieldset_def(fds, &(zconf.probe_module->fields),
+		sizeof(zconf.probe_module->fields)/sizeof(fielddef_t));
+	gen_fieldset_def(fds, &(sys_fields),
+		sizeof(sys_fields)/sizeof(fielddef_t));
+	// find the fields we need for the framework
+	zconf.fs_conf.success_index =
+			fs_get_index_by_name(fds, "success");	
+	if (zconf.fs_conf.success_index < 0) {
+		log_fatal("fieldset", "probe module does not supply "
+				      "required success field.");
+	}
+	zconf.fs_conf.classification_index =
+			fs_get_index_by_name(fds, "classification");
+	if (zconf.fs_conf.classification_index < 0) {
+		log_fatal("fieldset", "probe module does not supply "
+				      "required packet classification field.");
+	}
+	// process the list of requested output fields.
+	if (args.output_fields_given) {
+		zconf.raw_output_fields = args.output_fields_arg;
+	} else {
+		zconf.raw_output_fields = (char*) "saddr";
+	}	
+	fs_split_string(args.output_fields_arg, &(zconf.output_fields_len),
+			&(zconf.output_fields));
+	for (int i=0; i < zconf.output_fields_len; i++) {
+		log_trace("zmap", "requested output field (%i): %s",
+				zconf.output_fields[i]);
+	}
+	// generate a translation that can be used to convert output
+	// from a probe module to the input for an output module
 
 	SET_IF_GIVEN(zconf.output_filename, output_file);
 	SET_IF_GIVEN(zconf.blacklist_filename, blacklist_file);
@@ -385,36 +438,7 @@ int main(int argc, char *argv[])
 	zconf.senders = args.sender_threads_arg;
 	zconf.log_level = args.verbosity_arg;
 
-	zconf.output_module = get_output_module_by_name(args.output_module_arg);
-	if (!zconf.output_module) {
-	  fprintf(stderr, "%s: specified output module (%s) does not exist\n",
-		  CMDLINE_PARSER_PACKAGE, args.output_module_arg);
-	  exit(EXIT_FAILURE);
-	}
-	zconf.probe_module = get_probe_module_by_name(args.probe_module_arg);
-	if (!zconf.probe_module) {
-		fprintf(stderr, "%s: specified probe module (%s) does not exist\n",
-				CMDLINE_PARSER_PACKAGE, args.probe_module_arg);
-	  exit(EXIT_FAILURE);
-	}
-	// we need to generate a master fielddef list
-
-	// process the list of output fields.
-	if (args.output_fields_given) {
-		zconf.raw_output_fields = zopt.output_fields;
-		fs_split_string(zopt.output_fields, &(zconf.output_fields),
-				&(zconf.output_fields_len));	
-	} else {
-		zconf.output_fields = {"saddr"};
-		zconf.num_output_fields = 1;
-	}
-	// check the list of requested fields to see if they are available
-	// with the selected probe module.
-	for (int i=0; i < zonf.num_output_fields; i++) {
-		fs_check
-
-	}
-
+	
 
 	if (zconf.probe_module->port_args) {
 		if (args.source_port_given) {