I have a server with several sites hosted on it. Randomly, a site user will find that they can no longer connect to any of the sites on the server - but they can connect to the rest of the Internet. When this happens, the sites themselves are fine and everyone else can connect without any problems.
The only way the affected user can view sites on the server again is to reboot their router - at which point everything is fine.
Can anyone shed any light on why this would happen? I have a CentOS (Red Hat Enterprise) Linux server with DirectAdmin, Apache, PHP/MySQL - the usual. I'm thinking that there must be some kind of network setting which is allowing this to happen, but I can't for the life of me work out what it is.
That sounds odd... when they reboot their router, do they get a new IP address?
The only thing I can think of is that your firewall (if you have one) is blocking their IP address, so when they reboot their router they are given a new IP address from their ISP thus allowing them to connect again to your server.