diff --git a/http2irc.py b/http2irc.py
index 1238f0f..039c078 100644
--- a/http2irc.py
+++ b/http2irc.py
@@ -129,12 +129,14 @@ class Config(dict):
 					raise InvalidConfig(f'Invalid map {key!r} web path: collides with map {seenWebPaths[map_["webpath"]]!r}')
 				seenWebPaths[map_['webpath']] = key
 
-				if 'ircchannel' in map_:
-					if not isinstance(map_['ircchannel'], str):
-						raise InvalidConfig(f'Invalid map {key!r} IRC channel: not a string')
-					if not map_['ircchannel'].startswith('#') and not map_['ircchannel'].startswith('&'):
-						raise InvalidConfig(f'Invalid map {key!r} IRC channel: does not start with # or &')
-					#TODO Check if it's a valid name per IRC spec
+				if 'ircchannel' not in map_:
+					map_['ircchannel'] = f'#{key}'
+				if not isinstance(map_['ircchannel'], str):
+					raise InvalidConfig(f'Invalid map {key!r} IRC channel: not a string')
+				if not map_['ircchannel'].startswith('#') and not map_['ircchannel'].startswith('&'):
+					raise InvalidConfig(f'Invalid map {key!r} IRC channel: does not start with # or &')
+				if any(x in map_['ircchannel'][1:] for x in (' ', '\x00', '\x07', '\r', '\n', ',')):
+					raise InvalidConfig(f'Invalid map {key!r} IRC channel: contains forbidden characters')
 
 				if 'auth' in map_:
 					if map_['auth'] is not False and not isinstance(map_['auth'], str):
@@ -156,8 +158,7 @@ class Config(dict):
 		# Fill in default values for the maps
 		for key, map_ in obj['maps'].items():
 			# webpath is already set above for duplicate checking
-			if 'ircchannel' not in map_:
-				map_['ircchannel'] = f'#{key}'
+			# ircchannel is set above for validation
 			if 'auth' not in map_:
 				map_['auth'] = False
 			if 'module' not in map_: