diff -urp pads-1.2.orig/doc/pads.conf.8 pads-1.2/doc/pads.conf.8
--- pads-1.2.orig/doc/pads.conf.8	2008-07-08 14:28:29.000000000 -0400
+++ pads-1.2/doc/pads.conf.8	2008-07-08 17:36:41.000000000 -0400
@@ -69,9 +69,12 @@ assets found in these networks will be r
 This output plugin displays PADS data to the screen.  When using the
 configuration file, it defaults to off.
 
-.IP "output csv: <filename>"
+.IP "output csv: <filename> [readonly]"
 This output plugin writes PADS data to a CSV file.  Optionally, a CSV filename
-can be specified as an argument.
+can be specified as an argument. If you want the file used only to populate
+the internal known assets list but never be updated, then use the readonly
+option. This would be handy when you have a baseline and want to use it for
+intrusion detection.
 
 .IP "output fifo: <filename>"
 This output plugin writes PADS data to a FIFO file.  Optionally, a FIFO
diff -urp pads-1.2.orig/etc/pads.conf pads-1.2/etc/pads.conf
--- pads-1.2.orig/etc/pads.conf	2008-07-08 14:28:29.000000000 -0400
+++ pads-1.2/etc/pads.conf	2008-07-08 17:36:51.000000000 -0400
@@ -67,7 +67,9 @@ pid_file /var/run/pads.pid
 # output:  csv
 # -------------------------
 # This output plugin writes PADS data to a CSV file.  Optionally, a CSV filename
-# can be specified as an argument.
+# can be specified as an argument. If you want the file used only to populate
+# the internal known assets list but never be updated, then add the readonly
+# option.
 output csv: /etc/pads-assets.csv
 
 # output:  fifo
@@ -81,5 +83,4 @@ output csv: /etc/pads-assets.csv
 # This output plugin writes PADS data as IDMEF alerts via prelude.  Optionally
 # you can add a profile name if you want something different than the default
 # of pads.
-#
 #output prelude: pads
diff -urp pads-1.2.orig/src/output/output-csv.c pads-1.2/src/output/output-csv.c
--- pads-1.2.orig/src/output/output-csv.c	2008-07-08 14:28:29.000000000 -0400
+++ pads-1.2/src/output/output-csv.c	2008-07-08 17:36:41.000000000 -0400
@@ -60,6 +60,9 @@ setup_output_csv (void)
 	log_message("warning:  'register_output_plugin' in function 'setup_output_csv' failed.");
 	return -1;
     }
+    output_csv_conf.filename = NULL;
+    output_csv_conf.file = NULL;
+    output_csv_conf.readonly = 0;
 
     return 0;
 }
@@ -81,22 +84,39 @@ init_output_csv (bstring filename)
     verbose_message("Initializing CSV output plugin.");
 
     /* Make sure filename isn't NULL. */
-    if (filename != NULL)
-	output_csv_conf.filename = bstrcpy(filename);
-    else
+    if (filename != NULL) {
+        /* Parse the args looking for readonly and file name */
+        int i;
+        struct bstrList *list = bsplit(filename, ' ');
+        if (list->qty > 2) {
+            err_message("Too many args for output csv");
+            return -1;
+        }
+        for (i=0; i< list->qty; i++) {
+            if (biseqcstr(list->entry[i], "readonly") == 1) {
+                output_csv_conf.readonly = 1;
+                verbose_message("Using csv file in read only mode.");
+            } else if (output_csv_conf.filename == NULL)
+	        output_csv_conf.filename = bstrcpy(filename);
+            else
+                err_message("Unrecognized output csv option");
+	} 
+        bstrListDestroy(list);
+    } else
 	output_csv_conf.filename = bfromcstr("assets.csv");
 
     /* Check to see if *filename exists. */
     if ((fp = fopen((char *)bdata(output_csv_conf.filename), "r")) == NULL) {
 
-	/* File does not exist, create new.. */
-	if ((output_csv_conf.file = fopen((char *)bdata(output_csv_conf.filename), "w")) != NULL) {
-	    fprintf(output_csv_conf.file, "asset,port,proto,service,application,discovered\n");
-	    fflush(output_csv_conf.file);
-
-	} else {
-	    err_message("Cannot open file %s!", bdata(output_csv_conf.filename));
-	    return -1;
+	if (output_csv_conf.readonly == 0) {
+	    /* File does not exist, create new.. */
+	    if ((output_csv_conf.file = fopen((char *)bdata(output_csv_conf.filename), "w")) != NULL) {
+	        fprintf(output_csv_conf.file, "asset,port,proto,service,application,discovered\n");
+	        fflush(output_csv_conf.file);
+	    } else {
+	        err_message("Cannot open file %s!", bdata(output_csv_conf.filename));
+	        return -1;
+            }
 	}
 
     } else {
@@ -105,11 +125,14 @@ init_output_csv (bstring filename)
 	fclose(fp);
 	read_report_file();
 
-	/* Open file and assign it to the global FILE pointer.  */
-	if ((output_csv_conf.file = fopen((char *)bdata(output_csv_conf.filename), "a")) == NULL) {
-	    err_message("Cannot open file %s!", bdata(output_csv_conf.filename));
-	    return -1;
-	}
+	if (output_csv_conf.readonly == 0) {
+	    /* Open file and assign it to the global FILE pointer.  */
+	    if ((output_csv_conf.file = fopen((char *)bdata(output_csv_conf.filename), "a")) == NULL) {
+	        err_message("Cannot open file %s!",
+                            bdata(output_csv_conf.filename));
+	        return -1;
+	    }
+        }
     }
 
     return 0;
@@ -255,6 +278,9 @@ parse_raw_report (bstring line)
 int
 print_asset_csv (Asset *rec)
 {
+    if (output_csv_conf.readonly)
+        return 0;
+
     if (output_csv_conf.file != NULL) {
 	if (gc.hide_unknowns == 0 || ((biseqcstr(rec->service, "unknown") != 0) &&
 		    (biseqcstr(rec->application, "unknown") != 0))) {
@@ -285,6 +311,9 @@ print_asset_csv (Asset *rec)
 int
 print_arp_asset_csv (ArpAsset *rec)
 {
+    if (output_csv_conf.readonly)
+        return 0;
+
     /* Print to File */
     if (output_csv_conf.file != NULL) {
 	if (rec->mac_resolved != NULL) {
diff -urp pads-1.2.orig/src/output/output-csv.h pads-1.2/src/output/output-csv.h
--- pads-1.2.orig/src/output/output-csv.h	2008-07-08 14:28:29.000000000 -0400
+++ pads-1.2/src/output/output-csv.h	2008-07-08 17:36:41.000000000 -0400
@@ -50,6 +50,7 @@ typedef struct _OutputCSVConf
 {
     FILE *file;
     bstring filename;
+    int readonly;
 } OutputCSVConf;