Blocking comment spammers on an Ikiwiki blog
Despite comments on my ikiwiki blog being fully moderated, spammers have been increasingly posting link spam comments on my blog. While I used to use the blogspam plugin, the underlying service was likely retired circa 2017 and its public repositories are all archived.
It turns out that there is a relatively simple way to drastically reduce the amount of spam submitted to the moderation queue: ban the datacentre IP addresses that spammers are using.
While I do want to eliminate this source of spam, I don't want to block these datacentre IP addresses outright since legitimate users could be using these servers as VPN endpoints or crawlers.
I therefore added the following to my Apache config to restrict the CGI endpoint (used only for write operations such as commenting):
I will likely automate this process in the future, but at the moment my blog can go for a week without a single spam message (down from dozens every day). It's possible that I've already cut off the worst offenders.
