Why is the spam checking taking so long? It takes 30 seconds for a single message!

Of course it should not take that long. Under normal circumstances the spam checking, even with the standard 8 or 9 blacklists all active only takes less than two or three seconds.

If it takes longer than there the cause is most probably one of two possible problems:

  1. One of the used antispam servers does not exist any longer or is slow to respond. NOTE: As of 05-2007 the popular list.dsbl.org is no longer available. Please remove this list from your configuration!
  2. A problem with the DNS set up on the machine or network. In most cases it's the problem of a defunct or no longer available DNS server entered previously in the list of DNS servers to contact that resides on your router or firewall. Please check the router list of DNS servers and reduce it down to only one DNS server. That will solve the problem.

    Why DNS? The internet antispam blacklist servers are querried by using DNS lookups. POPcon creates a name to be looked up by combining the IP adress to be checked with the blacklist server name. If the resulting name lookup is successful it means the IP is listed. If the lookup fails (nothing returned) then the IP was not listed. If a bad DNS server is listed in your router then it will not normally be a problem with normal, working DNS lookups because the router just contacts the first operating DNS server if the lookup is successful. Only with POPcon's many lookups destined to fail this becomes a problem because after the first DNS server fails the lookup the router will try all the other DNS servers listed and will run into a timeout with any DNS server listed but not available.