What does a “MaxConnPerIP” error message mean?

Our Web servers allow each connecting IP address to make a fairly large number of simultaneous connections (usually 50). This is far more than normal Web browser software or legitimate search engines ever use.

If a connecting IP address tries to exceed the allowed number of connections, the extra ones will be blocked with a line like this in in the error log:

Rejecting connection from (50 simultaneous connections from this IP address allowed by MaxConnPerIP, 52 connections already established)

If we didn’t do this, your website could easily be overwhelmed by malicious or misconfigured software that prevents human visitors from being able to access the site.

So this message doesn’t indicate a problem with your site. It means that our servers have protected you from a problem that would happen if we allowed these connections to your site.

You can ignore messages like these in the error log unless it’s directly affecting something you’re doing (such as somehow blocking your own IP address).

Can I increase the limit?

If this is blocking your own IP address, you can increase the maximum number of allowed connections with a line in your .htaccess file like this:

MaxConnPerIP 80

This would allow a single IP address to make 80 simultaneous connections to your site. (Although you can enter numbers larger than 80, you’ll then reach the number of simultaneous connections allowed by our separate firewall, so it will act as if you’d used “80”.)