We couldn’t get to google maps today. We recently adjusted the firewall seetings in our BiPAC 7404VGP but didn’t make any changes that should have affected google maps. Looking at Status / Event Log showed me that an address with a Source Port of 80 was being blocked by a blacklist. By going into the Firewall / Intrusion Detection section and clicking the Clear Blacklist button fixed the problem nicely.
Why did I emphasis that it was the Source port? Our firewall is constantly blocking all manner of garbage that’s trying to get into our computer. Understanding how TCP/IP traffic works let me recognise the good bit of data amongst the garbage. A more in-depth explanation can be found HERE.