Here is some info from DNS Stuff. I looks like everything is ok but you may want to fix these.
FAIL Open DNS servers ERROR: One or more of your nameservers reports that it is an open DNS server. This usually means that anyone in the world can query it for domains it is not authoritative for (it is possible that the DNS server advertises that it does recursive lookups when it does not, but that shouldn't happen). This can cause an excessive load on your DNS server. Also, it is strongly discouraged to have a DNS server be both authoritative for your domain and be recursive (even if it is not open), due to the potential for cache poisoning (with no recursion, there is no cache, and it is impossible to poison it). Also, the bad guys could use your DNS server as part of an attack, by forging their IP address. Problem record(s) are:
Server 70.86.43.74 reports that it will do recursive lookups. [test] Server 70.86.43.75 reports that it will do recursive lookups. [test] See this page for info on closing open DNS servers.
WARN SOA EXPIRE value WARNING: Your SOA EXPIRE time is : 172800 seconds. This seems a bit low. You should consider increasing this value to about 1209600 to 2419200 seconds (2 to 4 weeks). RFC1912 suggests 2-4 weeks. This is how long a secondary/slave nameserver will wait before considering its DNS data stale if it can't reach the primary nameserver.
WARN Nameservers on separate class C's WARNING: All of your nameservers (listed at the parent nameservers) are in the same Class C (technically, /24) address space, which means that they are probably at the same physical location. Your nameservers should be at geographically dispersed locations. You should not have all of your nameservers at the same location. RFC2182 3.1 goes into more detail about secondary nameserver location.
Please see here for full report.
http://www.dnsstuff.com/tool/dnsreport.ch?...566ee8e1cc66019