When our collection of virtual servers got to a certain size, we moved from hosts files to a DNS server. However, we still have to update the firewall rules on every machine each time a new server is added. (Since all virtual machines at the provider can see each other, including other customers machines, we need to a list of trusted addresses in the iptables rules)
What techniques do people use to centralise administration of IPTables configuration? At the moment the best we've got is uploading a new ip list to each machine and restarting the firewall. Is there a better way?
[It would be wonderful if we could somehow tie IPTables trusted addesses to our DNS - eg. anything defined in our DNS is classed as a trusted address - but I assuming that nothing like this is possible]