diff --git a/src/acl.c b/src/acl.c
index 155bb145..be004a9d 100644
--- a/src/acl.c
+++ b/src/acl.c
@@ -130,7 +130,7 @@ init_firewall()
     if (pclose(fp) == 0) {
         mode = FIREWALLD_MODE;
     } else {
-        /* Check whether we have permission to operate iptables. 
+        /* Check whether we have permission to operate iptables.
 	 * Note that checking `iptables --version` is insufficient:
          * eg, running within a child user namespace.
 	 */
@@ -223,6 +223,16 @@ set_firewall_rule(char *addr, int add)
     return 0;
 }
 
+static void
+free_firewall_rule(void *key, void *element)
+{
+    if (key == NULL)
+        return;
+    char *addr = (char *)key;
+    set_firewall_rule(addr, 0);
+    ss_free(element);
+}
+
 #endif
 
 void
@@ -231,8 +241,10 @@ init_block_list()
     // Initialize cache
 #ifdef __linux__
     init_firewall();
-#endif
+    cache_create(&block_list, 256, free_firewall_rule);
+#else
     cache_create(&block_list, 256, NULL);
+#endif
 }
 
 void
@@ -248,12 +260,6 @@ int
 remove_from_block_list(char *addr)
 {
     size_t addr_len = strlen(addr);
-
-#ifdef __linux__
-    if (cache_key_exist(block_list, addr, addr_len))
-        set_firewall_rule(addr, 0);
-#endif
-
     return cache_remove(block_list, addr, addr_len);
 }
 
diff --git a/src/cache.c b/src/cache.c
index 127792d9..ad921d5b 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -47,7 +47,7 @@
  */
 int
 cache_create(struct cache **dst, const size_t capacity,
-             void (*free_cb)(void *element))
+             void (*free_cb)(void *key, void *element))
 {
     struct cache *new = NULL;
 
@@ -92,7 +92,7 @@ cache_delete(struct cache *cache, int keep_data)
             HASH_DEL(cache->entries, entry);
             if (entry->data != NULL) {
                 if (cache->free_cb) {
-                    cache->free_cb(entry->data);
+                    cache->free_cb(entry->key, entry->data);
                 } else {
                     ss_free(entry->data);
                 }
@@ -132,7 +132,7 @@ cache_clear(struct cache *cache, ev_tstamp age)
             HASH_DEL(cache->entries, entry);
             if (entry->data != NULL) {
                 if (cache->free_cb) {
-                    cache->free_cb(entry->data);
+                    cache->free_cb(entry->key, entry->data);
                 } else {
                     ss_free(entry->data);
                 }
@@ -173,7 +173,7 @@ cache_remove(struct cache *cache, char *key, size_t key_len)
         HASH_DEL(cache->entries, tmp);
         if (tmp->data != NULL) {
             if (cache->free_cb) {
-                cache->free_cb(tmp->data);
+                cache->free_cb(tmp->key, tmp->data);
             } else {
                 ss_free(tmp->data);
             }
@@ -291,7 +291,7 @@ cache_insert(struct cache *cache, char *key, size_t key_len, void *data)
             HASH_DELETE(hh, cache->entries, entry);
             if (entry->data != NULL) {
                 if (cache->free_cb) {
-                    cache->free_cb(entry->data);
+                    cache->free_cb(entry->key, entry->data);
                 } else {
                     ss_free(entry->data);
                 }
diff --git a/src/cache.h b/src/cache.h
index 9e97a4ad..0ec98f55 100644
--- a/src/cache.h
+++ b/src/cache.h
@@ -47,11 +47,11 @@ struct cache_entry {
 struct cache {
     size_t max_entries;              /**<Amount of entries this cache object can hold */
     struct cache_entry *entries;     /**<Head pointer for uthash */
-    void (*free_cb) (void *element); /**<Callback function to free cache entries */
+    void (*free_cb) (void *key, void *element); /**<Callback function to free cache entries */
 };
 
 int cache_create(struct cache **dst, const size_t capacity,
-                        void (*free_cb)(void *element));
+                        void (*free_cb)(void *key, void *element));
 int cache_delete(struct cache *cache, int keep_data);
 int cache_clear(struct cache *cache, ev_tstamp age);
 int cache_lookup(struct cache *cache, char *key, size_t key_len, void *result);
diff --git a/src/udprelay.c b/src/udprelay.c
index 57639f80..1a59bb41 100644
--- a/src/udprelay.c
+++ b/src/udprelay.c
@@ -1297,7 +1297,7 @@ CLEAN_UP:
 }
 
 void
-free_cb(void *element)
+free_cb(void *key, void *element)
 {
     remote_ctx_t *remote_ctx = (remote_ctx_t *)element;