diff --git a/fetch.py b/fetch.py
index 8ac8b67..d85b75f 100644
--- a/fetch.py
+++ b/fetch.py
@@ -97,6 +97,26 @@ def is_usable_proxy(proxy):
 	return True
 
 _known_proxies = {}
+
+def init_known_proxies(proxydb):
+	"""Initialize known proxies cache from database."""
+	global _known_proxies
+	if _known_proxies:
+		return
+	known = proxydb.execute('SELECT proxy FROM proxylist').fetchall()
+	for k in known:
+		_known_proxies[k[0]] = True
+
+def add_known_proxies(proxies):
+	"""Add proxies to known cache."""
+	global _known_proxies
+	for p in proxies:
+		_known_proxies[p] = True
+
+def is_known_proxy(proxy):
+	"""Check if proxy is in known cache."""
+	return proxy in _known_proxies
+
 def extract_proxies(content, proxydb):
 	matches = re.findall(r'([0-9]+(?:\.[0-9]+){3}:[0-9]{2,5})[\D$]', cleanhtml(content))