diff --git a/fail2ban/server/filter.py b/fail2ban/server/filter.py
index c4f29878..c309bbb2 100644
--- a/fail2ban/server/filter.py
+++ b/fail2ban/server/filter.py
@@ -458,7 +458,10 @@ class Filter(JailThread):
 			return
 		# Create IP address object
 		ip = IPAddr(ipstr)
-
+		# Avoid exact duplicates
+		if ip in self.__ignoreIpList:
+			logSys.warn("  Ignore duplicate %r (%r), already in ignore list", ip, ipstr)
+			return
 		# log and append to ignore list
 		logSys.debug("  Add %r to ignore list (%r)", ip, ipstr)
 		self.__ignoreIpList.append(ip)
diff --git a/fail2ban/tests/servertestcase.py b/fail2ban/tests/servertestcase.py
index 0b888407..1d963d0c 100644
--- a/fail2ban/tests/servertestcase.py
+++ b/fail2ban/tests/servertestcase.py
@@ -441,17 +441,16 @@ class Transmitter(TransmitterBase):
 		self.assertEqual(
 			self.transm.proceed(["set", self.jailName, "addignoreip", value]),
 			(0, [value]))
-		# Will allow duplicate
-		#NOTE: Should duplicates be allowed, or silent ignore like logpath?
+		# Duplicates ignored
 		self.assertEqual(
 			self.transm.proceed(["set", self.jailName, "addignoreip", value]),
-			(0, [value, value]))
+			(0, [value]))
 		self.assertEqual(
 			self.transm.proceed(["get", self.jailName, "ignoreip"]),
-			(0, [value, value]))
+			(0, [value]))
 		self.assertEqual(
 			self.transm.proceed(["set", self.jailName, "delignoreip", value]),
-			(0, [value]))
+			(0, []))
 
 		self.assertEqual(
 			self.transm.proceed(["get", self.jailName, "ignoreself"]),