I have multiple DNS servers with DHCP scope options pointing to two of my DNS servers. The other day I took one of my DNS servers off line for maintenance thinking that the second DNS server would pick up the slack while I had the other server down. It didn't. I'm just wondering why this second server didn't continue serving the zones. I have my SOA expiration time frame set to 1 day so shouldn't the secondary have continued to answer requests on my zones for that amount of time? I'd like to be able to bring either server down for maintenance and not have to worry about this again. These are internal servers answering internal requests.