This has come up in the past so I thought I’d mention it here. Sometimes, apparently, Ticketmaster.com blocks our ip address, denying patrons (and us) access to their site. You’ll see a message like this:
See: http://help.ticketmaster.com/why-am-i-getting-a-blocked-forbidden-or-403-error-message/
See: http://ticketcrusader.com/ticketmaster-ip-block-tips-tricks/
Because they are seeing the same IP address hitting their site repeatedly, our activity appears malicious, so they block us. Boo!
I’ve written to them to see about whitelisting us in the future, but it is a problem out of our control. It isn’t our firewall, or our filtering policies. The block is coming from Ticketmaster’s side.