diff --git a/client/castApp/src/Makefile b/client/castApp/src/Makefile
index 8d95a8e..0cb31e8 100644
--- a/client/castApp/src/Makefile
+++ b/client/castApp/src/Makefile
@@ -48,6 +48,11 @@ testAddEnvVars_SRCS += testAddEnvVars.c
 testAddEnvVars_SYS_LIBS_WIN32 = ws2_32
 TESTS += testAddEnvVars
 
+TESTPROD_HOST += testAddExcludePattern
+testAddExcludePattern_SRCS += testAddExcludePattern.c
+testAddExcludePattern_SYS_LIBS_WIN32 = ws2_32
+TESTS += testAddExcludePattern
+
 TESTSCRIPTS_HOST += $(TESTS:%=%.t)
 ifneq ($(filter $(T_A),$(CROSS_COMPILER_RUNTEST_ARCHS)),)
 TESTPROD = $(TESTPROD_HOST)
diff --git a/client/castApp/src/caster.c b/client/castApp/src/caster.c
index 7ae2cea..15da501 100644
--- a/client/castApp/src/caster.c
+++ b/client/castApp/src/caster.c
@@ -114,14 +114,21 @@ void casterInit(caster_t *self)
     self->onmsg = &casterShowMsgDefault;
     self->current = casterStateInit;
     self->timeout = reccastTimeout;
+    ellInit(&self->extra_envs);
+    ellInit(&self->exclude_patterns);
 
     if(shSocketPair(self->wakeup))
         errlogPrintf("Error: casterInit failed to create shutdown socket: %d\n", SOCKERRNO);
 }
 
+static void nodeFree(void *node) {
+    string_list_t *temp = (string_list_t *)node;
+    free(temp->item_str);
+    free(temp);
+}
+
 void casterShutdown(caster_t *self)
 {
-    int i;
     epicsUInt32 junk = htonl(0xdeadbeef);
 
     epicsMutexMustLock(self->lock);
@@ -136,10 +143,11 @@ void casterShutdown(caster_t *self)
     epicsEventMustWait(self->shutdownEvent);
 
     epicsMutexMustLock(self->lock);
-    for (i = 0; i < self->num_extra_envs; i++) {
-        free(self->extra_envs[i]);
-    }
-    free(self->extra_envs);
+    ellFree2(&self->extra_envs, &nodeFree);
+    epicsMutexUnlock(self->lock);
+
+    epicsMutexMustLock(self->lock);
+    ellFree2(&self->exclude_patterns, &nodeFree);
     epicsMutexUnlock(self->lock);
 
     epicsEventDestroy(self->shutdownEvent);
diff --git a/client/castApp/src/caster.h b/client/castApp/src/caster.h
index a4172df..659ff92 100644
--- a/client/castApp/src/caster.h
+++ b/client/castApp/src/caster.h
@@ -12,6 +12,7 @@
 #include <epicsEvent.h>
 #include <epicsMutex.h>
 #include <compilerDependencies.h>
+#include <ellLib.h>
 
 #include "sockhelpers.h"
 
@@ -35,6 +36,11 @@ typedef enum {
     casterStateDone,
 } casterState;
 
+typedef struct {
+    ELLNODE node;
+    char *item_str;
+} string_list_t;
+
 typedef struct _caster_t {
     double timeout;
 
@@ -68,8 +74,9 @@ typedef struct _caster_t {
     int shutdown;
     char lastmsg[MAX_STRING_SIZE];
 
-    char **extra_envs;
-    int num_extra_envs;
+    ELLLIST extra_envs;
+
+    ELLLIST exclude_patterns;
 
 } caster_t;
 
@@ -101,6 +108,9 @@ int casterPushPDB(void *junk, caster_t *caster);
 epicsShareFunc
 void addReccasterEnvVars(caster_t* self, int argc, char **argv);
 
+epicsShareFunc
+void addReccasterExcludePattern(caster_t* self, int argc, char **argv);
+
 /* internal */
 
 epicsShareFunc
diff --git a/client/castApp/src/castinit.c b/client/castApp/src/castinit.c
index 4efe4e7..9326b5e 100644
--- a/client/castApp/src/castinit.c
+++ b/client/castApp/src/castinit.c
@@ -74,7 +74,6 @@ static void casthook(initHookState state)
 void addReccasterEnvVars(caster_t* self, int argc, char **argv)
 {
     size_t i, j;
-    int ret = 0;
 
     argv++; argc--; /* skip function arg */
     if(argc < 1) {
@@ -95,91 +94,54 @@ void addReccasterEnvVars(caster_t* self, int argc, char **argv)
         epicsMutexUnlock(self->lock);
         return;
     }
-    int new_extra_envs_size = self->num_extra_envs + argc;
-    int num_new_extra_envs = self->num_extra_envs;
 
-    char **new_extra_envs = calloc(new_extra_envs_size, sizeof(*new_extra_envs));
-    if(new_extra_envs == NULL) {
-        errlogSevPrintf(errlogMajor, "Error in memory allocation of new_extra_envs from addReccasterEnvVars\n");
-        epicsMutexUnlock(self->lock);
-        return;
-    }
-    /* copy self->extra_envs into new_extra_envs with room for new envs */
-    for(i=0; i < self->num_extra_envs; i++) {
-        if((new_extra_envs[i] = strdup(self->extra_envs[i])) == NULL) {
-            errlogSevPrintf(errlogMinor, "strdup error for copying %s to new_extra_envs[%zu] from addReccasterEnvVars\n", self->extra_envs[i], i);
-            ret = 1;
-            break;
-        }
-    }
     int found_dup;
     /* sanitize input - check for dups and empty args */
-    if(!ret) {
-        for(i=0; i < argc; i++) {
-            if(argv[i] == NULL) {
-                errlogSevPrintf(errlogMinor, "Arg is NULL for addReccasterEnvVars\n");
-                continue;
-            }
-            else if(argv[i][0] == '\0') {
-                errlogSevPrintf(errlogMinor, "Arg is empty for addReccasterEnvVars\n");
-                continue;
-            }
-            found_dup = 0;
-            /* check if dup in self->default_envs */
-            for(j = 0; default_envs[j]; j++) {
-                if(strcmp(argv[i], default_envs[j]) == 0) {
-                    found_dup = 1;
-                    errlogSevPrintf(errlogMinor, "Env var %s is already in env list sent by reccaster by default\n", argv[i]);
-                    break;
-                }
-            }
-            if(found_dup) {
-                continue;
-            }
-            /* check if dup in self->extra_envs */
-            for(j = 0; j < num_new_extra_envs; j++) {
-                if(new_extra_envs[j] == NULL) {
-                    continue;
-                }
-                if(strcmp(argv[i], new_extra_envs[j]) == 0) {
-                    found_dup = 1;
-                    errlogSevPrintf(errlogMinor, "Env var %s is already in extra_envs list\n", argv[i]);
-                    break;
-                }
-            }
-            if(found_dup) {
-                continue;
+    for(i=0; i < argc; i++) {
+        if(argv[i][0] == '\0') {
+            errlogSevPrintf(errlogMinor, "Arg is empty for addReccasterEnvVars\n");
+            continue;
+        }
+        found_dup = 0;
+        /* check if dup in self->default_envs */
+        for(j = 0; default_envs[j]; j++) {
+            if(strcmp(argv[i], default_envs[j]) == 0) {
+                found_dup = 1;
+                break;
             }
-            if((new_extra_envs[num_new_extra_envs] = strdup(argv[i])) == NULL) {
-                errlogSevPrintf(errlogMinor, "strdup error for copying %s to new_extra_envs[%d] from addReccasterEnvVars\n", argv[i], num_new_extra_envs);
-                ret = 1;
+        }
+        if(found_dup) {
+            errlogSevPrintf(errlogMinor, "Env var %s is already in env list sent by reccaster by default\n", argv[i]);
+            continue;
+        }
+        /* check if dup in self->extra_envs */
+        ELLNODE *cur = ellFirst(&self->extra_envs);
+        while (cur != NULL) {
+            string_list_t *temp = (string_list_t *)cur;
+            if (strcmp(argv[i], temp->item_str) == 0) {
+                found_dup = 1;
                 break;
             }
-            /* this is a valid arg and we have added the new env var to our array, increment new_extra_envs count */
-            num_new_extra_envs++;
+            cur = ellNext(cur);
         }
+        if(found_dup) {
+            errlogSevPrintf(errlogMinor, "Env var %s is already in extra_envs list\n", argv[i]);
+            continue;
+        }
+        string_list_t *new_list = malloc(sizeof(string_list_t));
+        if (new_list == NULL) {
+            errlogSevPrintf(errlogMajor, "Error in addReccasterEnvVars - malloc error for creating linked list node");
+            break;
+        }
+        new_list->item_str = strdup(argv[i]);
+        if (new_list->item_str == NULL) {
+            errlogSevPrintf(errlogMajor, "Error in addReccasterEnvVars - strdup error for copying %s to new->item_str from addReccasterEnvVars\n", argv[i]);
+            free(new_list);  /* frees if strdup fails */
+            break;
+        }
+        ellAdd(&self->extra_envs, &new_list->node);
     }
-    /* if we have no allocation issues and have at least one new env var that is valid, add to self->extra_envs */
-    if(!ret && num_new_extra_envs > self->num_extra_envs) {
-        /* from this point, nothing can fail */
-        char ** tmp;
-        tmp = self->extra_envs; /* swap pointers so we can clean up new_extra_envs on success/failure */
-        self->extra_envs = new_extra_envs;
-        new_extra_envs = tmp;
-
-        new_extra_envs_size = self->num_extra_envs; /* with swap of pointers also swap size */
-        self->num_extra_envs = num_new_extra_envs;
-    }
-    /* cleanup new_extra_envs[] on success or failure */
-    for(i = 0; i < new_extra_envs_size; i++) {
-        free(new_extra_envs[i]);
-    }
-    free(new_extra_envs);
     epicsMutexUnlock(self->lock);
-
-    if(ret) {
-        errlogSevPrintf(errlogMajor, "Error in addReccasterEnvVars - reccaster might not send the extra env vars specified\n");
-    }
 }
 
 static const iocshArg addReccasterEnvVarsArg0 = { "environmentVar", iocshArgArgv };
@@ -200,6 +162,74 @@ static void addReccasterEnvVarsCallFunc(const iocshArgBuf *args)
     addReccasterEnvVars(&thecaster, args[0].aval.ac, args[0].aval.av);
 }
 
+void addReccasterExcludePattern(caster_t* self, int argc, char **argv) {
+    size_t i;
+    argv++; argc--; /* skip function arg */
+    if (argc < 1) {
+        errlogSevPrintf(errlogMinor, "At least one argument expected for addReccasterExcludePattern\n");
+        return;
+    }
+    epicsMutexMustLock(self->lock);
+    if (self->shutdown) {
+        /* shutdown in progress, silent no-op */
+        epicsMutexUnlock(self->lock);
+        return;
+    }
+    /* error if called after iocInit() */
+    if (self->current != casterStateInit) {
+        errlogSevPrintf(errlogMinor, "addReccasterExcludePattern called after iocInit() when reccaster might already be connected. Not supported\n");
+        epicsMutexUnlock(self->lock);
+        return;
+    }
+
+    for (i = 0; i < argc; i++) {
+        if (argv[i][0] == '\0') {
+            errlogSevPrintf(errlogMinor, "Arg is empty for addReccasterExcludePattern\n");
+            continue;
+        }
+        /* check duplicates */
+        int dup = 0;
+        ELLNODE *cur = ellFirst(&self->exclude_patterns);
+        while (cur != NULL) {
+            string_list_t *temp = (string_list_t *)cur;
+            if (strcmp(argv[i], temp->item_str) == 0) {
+                dup = 1;
+                break;
+            }
+            cur = ellNext(cur);
+        }
+        if (dup) {
+            errlogSevPrintf(errlogMinor, "Duplicate pattern %s in addReccasterExcludePattern\n", argv[i]);
+            continue;
+        }
+        string_list_t *new_list = malloc(sizeof(string_list_t));
+        if (new_list == NULL) {
+            errlogSevPrintf(errlogMajor, "Error in addReccasterExcludePattern - malloc error for creating linked list node");
+            break;
+        }
+        new_list->item_str = strdup(argv[i]);
+        if (new_list->item_str == NULL) {
+            errlogSevPrintf(errlogMajor, "Error in addReccasterExcludePattern - strdup error for copying %s to new->item_str from addReccasterExcludePattern\n", argv[i]);
+            free(new_list);  /* frees if strdup fails */
+            break;
+        }
+        ellAdd(&self->exclude_patterns, &new_list->node);
+    }
+    epicsMutexUnlock(self->lock);
+}
+
+static const iocshArg addReccasterExcludePatternArg0 = { "excludePattern", iocshArgArgv };
+static const iocshArg * const addReccasterExcludePatternArgs[] = { &addReccasterExcludePatternArg0 };
+static const iocshFuncDef addReccasterExcludePatternFuncDef = {
+    "addReccasterExcludePattern",
+    1,
+    addReccasterExcludePatternArgs
+};
+
+static void addReccasterExcludePatternCallFunc(const iocshArgBuf *args) {
+    addReccasterExcludePattern(&thecaster, args[0].aval.ac, args[0].aval.av);
+}
+
 static void reccasterRegistrar(void)
 {
     osiSockAttach();
@@ -210,6 +240,7 @@ static void reccasterRegistrar(void)
     thepriv.laststate=casterStateInit;
     strcpy(thepriv.lastmsg, "Initializing");
     iocshRegister(&addReccasterEnvVarsFuncDef,addReccasterEnvVarsCallFunc);
+    iocshRegister(&addReccasterExcludePatternFuncDef,addReccasterExcludePatternCallFunc);
 }
 
 static long init_record(void* prec)
diff --git a/client/castApp/src/dbcb.c b/client/castApp/src/dbcb.c
index 4d9cc04..e68239e 100644
--- a/client/castApp/src/dbcb.c
+++ b/client/castApp/src/dbcb.c
@@ -71,12 +71,15 @@ static int pushEnv(caster_t *caster)
     }
 
     epicsMutexMustLock(caster->lock);
-    for (i = 0; !ret && i < caster->num_extra_envs; i++) {
-        const char *val = getenv(caster->extra_envs[i]);
+    ELLNODE *env = ellFirst(&caster->extra_envs);
+    while (!ret && env != NULL) {
+        string_list_t *temp = (string_list_t *)env;
+        const char *val = getenv(temp->item_str);
         if (val && val[0] != '\0')
-            ret = casterSendInfo(caster, 0, caster->extra_envs[i], val);
+            ret = casterSendInfo(caster, 0, temp->item_str, val);
         if (ret)
-            casterMsg(caster, "Error sending env %s", caster->extra_envs[i]);
+            casterMsg(caster, "Error sending env %s", temp->item_str);
+        env = ellNext(env);
     }
     epicsMutexUnlock(caster->lock);
 
@@ -87,12 +90,21 @@ static int pushRecord(caster_t *caster, DBENTRY *pent)
 {
     dbCommon *prec = pent->precnode->precord;
     ssize_t rid;
+    ELLNODE *cur;
     int ret = 0;
     long status;
 
     if(dbIsAlias(pent))
         return 0;
 
+    cur = ellFirst(&caster->exclude_patterns);
+    while (cur != NULL) {
+        string_list_t *temp = (string_list_t *)cur;
+        if(epicsStrGlobMatch(prec->name, temp->item_str))
+            return 0;
+        cur = ellNext(cur);
+    }
+
     rid = casterSendRecord(caster, prec->rdes->name, prec->name);
     if(rid<=0)
         return rid;
diff --git a/client/castApp/src/testAddEnvVars.c b/client/castApp/src/testAddEnvVars.c
index fb81f12..93ed22d 100644
--- a/client/castApp/src/testAddEnvVars.c
+++ b/client/castApp/src/testAddEnvVars.c
@@ -14,7 +14,7 @@ static void testLog(void* arg, struct _caster_t* self)
 
 static void testAddEnvVarsX(void)
 {
-    int i;
+    int i = 0;
     caster_t caster;
     casterInit(&caster);
     caster.onmsg = &testLog;
@@ -29,7 +29,6 @@ static void testAddEnvVarsX(void)
         "BUILDING",
         "CONTACT",
         "DEVICE",
-        "Field",
         "FAMILY"
     };
     int expectedNumExtraEnvs = 0;
@@ -37,71 +36,84 @@ static void testAddEnvVarsX(void)
     testDiag("Testing addReccasterEnvVars with one good env");
     argvlist[1] = "SECTOR";
     argc = 2;
-    testOk1(caster.num_extra_envs==expectedNumExtraEnvs);
+    i = 0;
+    testOk1(caster.extra_envs.count==expectedNumExtraEnvs);
     addReccasterEnvVars(&caster, argc, argvlist);
     expectedNumExtraEnvs++;
-    testOk1(caster.num_extra_envs==expectedNumExtraEnvs);
-    for(i=0; i < expectedNumExtraEnvs; i++) {
-        testOk1(strcmp(caster.extra_envs[i], expectedExtraEnvs[i]) == 0);
+    testOk1(caster.extra_envs.count==expectedNumExtraEnvs);
+    ELLNODE *cur;
+    cur = ellFirst(&caster.extra_envs);
+    while (cur != NULL) {
+        string_list_t *temp = (string_list_t *)cur;
+        testOk1(strcmp(temp->item_str, expectedExtraEnvs[i]) == 0);
+        i++;
+        cur = ellNext(cur);
     }
 
     testDiag("Testing addReccasterEnvVars with two more good envs");
     argvlist[1] = "BUILDING";
     argvlist[2] = "CONTACT";
     argc = 3;
-    testOk1(caster.num_extra_envs==expectedNumExtraEnvs);
+    i = 0;
+    testOk1(caster.extra_envs.count==expectedNumExtraEnvs);
     addReccasterEnvVars(&caster, argc, argvlist);
     expectedNumExtraEnvs += 2;
-    testOk1(caster.num_extra_envs==expectedNumExtraEnvs);
-    for(i=0; i < expectedNumExtraEnvs; i++) {
-        testOk1(strcmp(caster.extra_envs[i], expectedExtraEnvs[i]) == 0);
+    testOk1(caster.extra_envs.count==expectedNumExtraEnvs);
+    cur = ellFirst(&caster.extra_envs);
+    while (cur != NULL) {
+        string_list_t *temp = (string_list_t *)cur;
+        testOk1(strcmp(temp->item_str, expectedExtraEnvs[i]) == 0);
+        i++;
+        cur = ellNext(cur);
     }
 
     testDiag("Testing addReccasterEnvVars with duplicate env");
     argvlist[1] = "SECTOR";
     argc = 2;
-    testOk1(caster.num_extra_envs==expectedNumExtraEnvs);
+    i = 0;
+    testOk1(caster.extra_envs.count==expectedNumExtraEnvs);
     addReccasterEnvVars(&caster, argc, argvlist);
-    testOk1(caster.num_extra_envs==expectedNumExtraEnvs);
-    for(i=0; i < expectedNumExtraEnvs; i++) {
-        testOk1(strcmp(caster.extra_envs[i], expectedExtraEnvs[i]) == 0);
+    testOk1(caster.extra_envs.count==expectedNumExtraEnvs);
+    cur = ellFirst(&caster.extra_envs);
+    while (cur != NULL) {
+        string_list_t *temp = (string_list_t *)cur;
+        testOk1(strcmp(temp->item_str, expectedExtraEnvs[i]) == 0);
+        i++;
+        cur = ellNext(cur);
     }
 
     testDiag("Testing addReccasterEnvVars with one dup and one good env");
     argvlist[1] = "CONTACT";
     argvlist[2] = "DEVICE";
     argc = 3;
-    testOk1(caster.num_extra_envs==expectedNumExtraEnvs);
+    i = 0;
+    testOk1(caster.extra_envs.count==expectedNumExtraEnvs);
     addReccasterEnvVars(&caster, argc, argvlist);
     expectedNumExtraEnvs++;
-    testOk1(caster.num_extra_envs==expectedNumExtraEnvs);
-    for(i=0; i < expectedNumExtraEnvs; i++) {
-        testOk1(strcmp(caster.extra_envs[i], expectedExtraEnvs[i]) == 0);
-    }
-
-    testDiag("Testing addReccasterEnvVars with NULL argument and then a good env");
-    argvlist[1] = NULL;
-    argvlist[2] = "Field";
-    argc = 3;
-    testOk1(caster.num_extra_envs==expectedNumExtraEnvs);
-    addReccasterEnvVars(&caster, argc, argvlist);
-    expectedNumExtraEnvs++;
-    testOk1(caster.num_extra_envs==expectedNumExtraEnvs);
-    for(i=0; i < expectedNumExtraEnvs; i++) {
-        testOk1(strcmp(caster.extra_envs[i], expectedExtraEnvs[i]) == 0);
+    testOk1(caster.extra_envs.count==expectedNumExtraEnvs);
+    cur = ellFirst(&caster.extra_envs);
+    while (cur != NULL) {
+        string_list_t *temp = (string_list_t *)cur;
+        testOk1(strcmp(temp->item_str, expectedExtraEnvs[i]) == 0);
+        i++;
+        cur = ellNext(cur);
     }
 
     testDiag("Testing addReccasterEnvVars with a good env and a dup of that env");
-    argvlist[1] = NULL;
+    argvlist[1] = "FAMILY";
     argvlist[2] = "FAMILY";
-    argvlist[3] = "FAMILY";
-    argc = 4;
-    testOk1(caster.num_extra_envs==expectedNumExtraEnvs);
+    argc = 3;
+    i = 0;
+    testOk1(caster.extra_envs.count==expectedNumExtraEnvs);
     addReccasterEnvVars(&caster, argc, argvlist);
     expectedNumExtraEnvs++;
-    testOk1(caster.num_extra_envs==expectedNumExtraEnvs);
-    for(i=0; i < expectedNumExtraEnvs; i++) {
-        testOk1(strcmp(caster.extra_envs[i], expectedExtraEnvs[i]) == 0);
+    testOk1(caster.extra_envs.count==expectedNumExtraEnvs);
+    cur = ellFirst(&caster.extra_envs);
+    while (cur != NULL) {
+        string_list_t *temp = (string_list_t *)cur;
+        testOk1(strcmp(temp->item_str, expectedExtraEnvs[i]) == 0);
+        i++;
+        cur = ellNext(cur);
     }
 
     testDiag("Testing addReccasterEnvVars with a env vars from default list");
@@ -111,11 +123,16 @@ static void testAddEnvVarsX(void)
     argvlist[4] = "RSRV_SERVER_PORT";
     argvlist[5] = "ENGINEER";
     argc = 6;
-    testOk1(caster.num_extra_envs==expectedNumExtraEnvs);
+    i = 0;
+    testOk1(caster.extra_envs.count==expectedNumExtraEnvs);
     addReccasterEnvVars(&caster, argc, argvlist);
-    testOk1(caster.num_extra_envs==expectedNumExtraEnvs);
-    for(i=0; i < expectedNumExtraEnvs; i++) {
-        testOk1(strcmp(caster.extra_envs[i], expectedExtraEnvs[i]) == 0);
+    testOk1(caster.extra_envs.count==expectedNumExtraEnvs);
+    cur = ellFirst(&caster.extra_envs);
+    while (cur != NULL) {
+        string_list_t *temp = (string_list_t *)cur;
+        testOk1(strcmp(temp->item_str, expectedExtraEnvs[i]) == 0);
+        i++;
+        cur = ellNext(cur);
     }
 
     epicsEventSignal(caster.shutdownEvent);
@@ -134,23 +151,16 @@ static void testAddEnvVarsBadInput(void)
 
     testDiag("Testing addReccasterEnvVars with no arguments");
     argc = 1;
-    testOk1(caster.num_extra_envs==0);
+    testOk1(caster.extra_envs.count==0);
     addReccasterEnvVars(&caster, argc, argvlist);
-    testOk1(caster.num_extra_envs==0);
+    testOk1(caster.extra_envs.count==0);
 
     testDiag("Testing addReccasterEnvVars with empty string argument");
     argvlist[1] = "";
     argc = 2;
-    testOk1(caster.num_extra_envs==0);
-    addReccasterEnvVars(&caster, argc, argvlist);
-    testOk1(caster.num_extra_envs==0);
-
-    testDiag("Testing addReccasterEnvVars with NULL argument");
-    argvlist[1] = NULL;
-    argc = 2;
-    testOk1(caster.num_extra_envs==0);
+    testOk1(caster.extra_envs.count==0);
     addReccasterEnvVars(&caster, argc, argvlist);
-    testOk1(caster.num_extra_envs==0);
+    testOk1(caster.extra_envs.count==0);
 
     epicsEventSignal(caster.shutdownEvent);
     casterShutdown(&caster);
@@ -158,7 +168,7 @@ static void testAddEnvVarsBadInput(void)
 
 MAIN(testAddEnvVars)
 {
-    testPlan(48);
+    testPlan(37);
     osiSockAttach();
     testAddEnvVarsX();
     testAddEnvVarsBadInput();
diff --git a/client/castApp/src/testAddExcludePattern.c b/client/castApp/src/testAddExcludePattern.c
new file mode 100644
index 0000000..8f0a9d6
--- /dev/null
+++ b/client/castApp/src/testAddExcludePattern.c
@@ -0,0 +1,173 @@
+#include <string.h>
+
+#include <epicsUnitTest.h>
+#include <testMain.h>
+
+#include "caster.h"
+
+void* epicsRtemsFSImage;
+
+static void testLog(void* arg, struct _caster_t* self)
+{
+    testDiag("ERR %s", self->lastmsg);
+}
+
+static void testAddExcludePatternX(void)
+{
+    int i = 0;
+    caster_t caster;
+    casterInit(&caster);
+    caster.onmsg = &testLog;
+
+    int argc;
+    char *argvlist[5];
+    argvlist[0] = "addReccasterExcludePattern";
+
+    char *expectedPatterns[] =
+    {
+        "*_",
+        "*__",
+        "*:Intrnl:*",
+        "*_internal",
+        "*exclude_me"
+    };
+    int expectedNumPatterns = 0;
+
+    testDiag("Testing addReccasterExcludePattern with one good env");
+    argvlist[1] = "*_";
+    argc = 2;
+    testOk1(caster.exclude_patterns.count==expectedNumPatterns);
+    addReccasterExcludePattern(&caster, argc, argvlist);
+    expectedNumPatterns++;
+    testOk1(caster.exclude_patterns.count==expectedNumPatterns);
+    ELLNODE *cur;
+    cur = ellFirst(&caster.exclude_patterns);
+    while (cur != NULL) {
+        string_list_t *temp = (string_list_t *)cur;
+        testOk1(strcmp(temp->item_str, expectedPatterns[i]) == 0);
+        i++;
+        cur = ellNext(cur);
+    }
+
+    testDiag("Testing addReccasterExcludePattern with two more patterns");
+    argvlist[1] = "*__";
+    argvlist[2] = "*:Intrnl:*";
+    argc = 3;
+    i = 0;
+    testOk1(caster.exclude_patterns.count==expectedNumPatterns);
+    addReccasterExcludePattern(&caster, argc, argvlist);
+    expectedNumPatterns += 2;
+    testOk1(caster.exclude_patterns.count==expectedNumPatterns);
+    cur = ellFirst(&caster.exclude_patterns);
+    while (cur != NULL) {
+        string_list_t *temp = (string_list_t *)cur;
+        testOk1(strcmp(temp->item_str, expectedPatterns[i]) == 0);
+        i++;
+        cur = ellNext(cur);
+    }
+
+    testDiag("Testing addReccasterExcludePattern with a duplicate pattern");
+    argvlist[1] = "*_";
+    argc = 2;
+    i = 0;
+    testOk1(caster.exclude_patterns.count==expectedNumPatterns);
+    addReccasterExcludePattern(&caster, argc, argvlist);
+    testOk1(caster.exclude_patterns.count==expectedNumPatterns);
+    cur = ellFirst(&caster.exclude_patterns);
+    while (cur != NULL) {
+        string_list_t *temp = (string_list_t *)cur;
+        testOk1(strcmp(temp->item_str, expectedPatterns[i]) == 0);
+        i++;
+        cur = ellNext(cur);
+    }
+
+    testDiag("Testing addReccasterExcludePattern with a new and a duplicate");
+    argvlist[1] = "*_internal";
+    argvlist[2] = "*__";
+    argc = 3;
+    i = 0;
+    testOk1(caster.exclude_patterns.count==expectedNumPatterns);
+    addReccasterExcludePattern(&caster, argc, argvlist);
+    expectedNumPatterns++;
+    testOk1(caster.exclude_patterns.count==expectedNumPatterns);
+    cur = ellFirst(&caster.exclude_patterns);
+    while (cur != NULL) {
+        string_list_t *temp = (string_list_t *)cur;
+        testOk1(strcmp(temp->item_str, expectedPatterns[i]) == 0);
+        i++;
+        cur = ellNext(cur);
+    }
+
+    testDiag("Testing addReccasterExcludePattern with two of the same pattern");
+    argvlist[1] = "*exclude_me";
+    argvlist[2] = "*exclude_me";
+    argc = 3;
+    i = 0;
+    testOk1(caster.exclude_patterns.count==expectedNumPatterns);
+    addReccasterExcludePattern(&caster, argc, argvlist);
+    expectedNumPatterns++;
+    testOk1(caster.exclude_patterns.count==expectedNumPatterns);
+    cur = ellFirst(&caster.exclude_patterns);
+    while (cur != NULL) {
+        string_list_t *temp = (string_list_t *)cur;
+        testOk1(strcmp(temp->item_str, expectedPatterns[i]) == 0);
+        i++;
+        cur = ellNext(cur);
+    }
+
+    testDiag("Testing addReccasterExcludePattern with duplicates in argv and exclude pattern list");
+    argvlist[1] = "*__";
+    argvlist[2] = "*__";
+    argc = 3;
+    i = 0;
+    testOk1(caster.exclude_patterns.count==expectedNumPatterns);
+    addReccasterExcludePattern(&caster, argc, argvlist);
+    testOk1(caster.exclude_patterns.count==expectedNumPatterns);
+    cur = ellFirst(&caster.exclude_patterns);
+    while (cur != NULL) {
+        string_list_t *temp = (string_list_t *)cur;
+        testOk1(strcmp(temp->item_str, expectedPatterns[i]) == 0);
+        i++;
+        cur = ellNext(cur);
+    }
+
+    epicsEventSignal(caster.shutdownEvent);
+    casterShutdown(&caster);
+}
+
+static void testAddExcludePatternBadInput()
+{
+    caster_t caster;
+    casterInit(&caster);
+    caster.onmsg = &testLog;
+
+    int argc;
+    char *argvlist[2];
+    argvlist[0] = "addReccasterExcludePattern";
+
+    testDiag("Testing addReccasterExcludePattern with no arguments");
+    argc = 1;
+    testOk1(caster.exclude_patterns.count==0);
+    addReccasterExcludePattern(&caster, argc, argvlist);
+    testOk1(caster.exclude_patterns.count==0);
+
+    testDiag("Testing addReccasterExcludePattern with empty string argument");
+    argvlist[1] = "";
+    argc = 2;
+    testOk1(caster.exclude_patterns.count==0);
+    addReccasterExcludePattern(&caster, argc, argvlist);
+    testOk1(caster.exclude_patterns.count==0);
+
+    epicsEventSignal(caster.shutdownEvent);
+    casterShutdown(&caster);
+}
+
+MAIN(testAddExcludePattern)
+{
+    testPlan(37);
+    osiSockAttach();
+    testAddExcludePatternX();
+    testAddExcludePatternBadInput();
+    osiSockRelease();
+    return testDone();
+}
diff --git a/client/iocBoot/iocdemo/st.cmd b/client/iocBoot/iocdemo/st.cmd
index fe81b08..35c72fa 100755
--- a/client/iocBoot/iocdemo/st.cmd
+++ b/client/iocBoot/iocdemo/st.cmd
@@ -23,6 +23,9 @@ epicsEnvSet("SECTOR", "mysector")
 addReccasterEnvVars("CONTACT", "SECTOR")
 addReccasterEnvVars("BUILDING")
 
+addReccasterExcludePattern("*_", "*__")
+addReccasterExcludePattern("*exclude_this")
+
 ## Load record instances
 dbLoadRecords("../../db/reccaster.db", "P=$(IOCSH_NAME):")
 dbLoadRecords("../../db/somerecords.db","P=$(IOCSH_NAME):")