mailgraph.pl on rowla.nuxx.net after Postgrey
(Click for full report…)

As mentioned yesterday I set up Postgrey on rowla.nuxx.net in order to implement greylisting and hopefully address the spam problem I (and others hosted on my box) have been having.

Well, it’s still less than 24 hours out, but it seems to be having a really big impact on the spam levels, with my personal accounts receiving only seven pieces of spam (all of which were flagged by SpamAssassin hitting my personal inbox. I’ve had no false negatives, and I haven’t yet seen any false positives. (Yes, I’ve been testing this and checking… Everything seems to work as designed.) For reference, I’d normally receive 300-500 automatically flagged pieces of spam per day, with 3-10 false negatives slipping through.

From that graph up there, one can see that Postgrey really seems to be doing the job. What can be seen (in the second graph) is that the rejected messages are way up, flagged spam is way down, meaning that the messages are being rejected and then not retried. The received messages (in the first graph) are way down, which directly correlates with the rejections.

Here is a snapshot from this morning of the daily, weekly, monthly, and yearly graphs. If you’d like to see the mostly-live graphs, here is rowla.nuxx.net’s mailgraph.pl.

Oh, and that dip on Saturday? That was the aforementioned outage caused by Waveform moving my server unexpectedly.

My received spam counts have been exploding lately, so I’ve enabled greylisting on nuxx.net via postgrey. It’s too early to tell, but looking at mailgraph shows that delivered message counts are WAY down, spam detections have almost gone away, and rejection counts are way up.

The way this works is by telling mail coming from unknown places to go away and try again later. Most spamming software doesn’t bother trying again later, but proper mail servers do. After the proper mail servers try again the mail is delivered, and that server is noted as being safe. So, because of this, mail coming to those I host from new destinations may be delayed for 5-15 minutes, but it’ll eventually get through.

If I host you and you are suddenly not getting mail which you expect to get, let me know and I’ll sort it out. It should work fine, though, just be patient. I’ll post more in a day or so once I know for sure how much counts are down.

For reference, I personally have been receiving 300-500 pieces of spam (with most of it flagged by SpamAssassin) per day, and it was just getting to be a bit much.