diff -r f899af683bbe -r aeb0d0788869 irc.py
--- a/irc.py	Sat Apr 11 21:02:54 2015 +0300
+++ b/irc.py	Sun Apr 19 19:45:42 2015 +0300
@@ -122,6 +122,7 @@
 
 			if line.startswith ("PING :"):
 				self.write ("PONG :%s" % line[6:])
+				self.send_all_now() # pings must be responded to immediately!
 			else:
 				words = line.split(" ")
 				if len(words) >= 2: