I had to disable antispam on my Postfix because rspamd accesses Redis on localhost (IPv4: 127.0.0.1) and ::1 (IPv6). ::1 responds extremely slowly when called multiple times in a row (redis-cli -h ::1 -p 6379 ping). This causes rspamd to time out, which in turn causes Postfix to enter a 300-second timeout. So far, I haven't found a way in the web GUI to configure Redis or rspamd to use only the IPv4 localhost address (127.0.0.1) to work around this problem. However, running `redis-cli -h 127.0.0.1 -p 6379 ping` does not experience any delay.