you right did not see that bit late hear could be the reason :)

I installed this mod yesterday and from then I have been bombarded with this spider AhrefsBot Spider I've tried adding them to this mod, but no joy.

It blocks that spider, how did you add it?

you need to block their IP, AhrefsBot has more than 1 IP

The whole purpose of this Mod is to block user agents, so you don't have to block IP addresses.

If the person put "AhrefsBot" in this Mod, it should be blocked no matter the IP.

I think you'll find that if you check WOL when arhefsbot is online and then choose to show useragent from the dropdown ahrefsbot isn't actually in their useragent, i think i posted about this to another user a few posts or so ago.

why not just put

*

/

it blocks all useragents and will only require standard 1 line box
this is what i have done

that will block everyone if using it in my mod!

Here's some UA's that ahrefs use
Mozilla/5.0 (compatible; AhrefsBot/1.0; +http://ahrefs.com/robot/)
Mozilla/5.0 (compatible; AhrefsBot/2.0; +http://ahrefs.com/robot/)
Mozilla/5.0 (compatible; AhrefsBot/3.0; +http://ahrefs.com/robot/)
Mozilla/5.0 (compatible; SiteBot/0.1; +http://www.sitebot.org/robot/)
Mozilla/5.0 (compatible; SiteBot/0.1; +http://www.sitebot.org/robot/),gzip(gfe)
Mozilla/5.0 (compatible; SiteBot/0.1; +http://www.sitebot.org/robot/),gzip(...(gfe),gzip(gfe)

So use SiteBot or Ahrefs as the banning UA's :)

for those who want to block blocks accesses through Facebook external hit

facebookexternalhit/1.0

I have had no problems, Ahrefsbot is in my collection, and I never see it hit my site anymore.

Pretty sure the OP is saying he sees "ahrefsbot" in his WOL after adding it to your mod.