troubleshooting any type of network intermittent problems can be a nightmare. Fortunately, Domain Name System protocol fairly easy and there are only so many things that can go wrong.

mature fruit
Start by eliminating obvious problems, such as the DNS is not available, WAN links are down, unplug the cable, no network cards, and so on. This kind of problems almost always manifest themselves in other respects won, because DNS? T generally the only thing affected. Because your client will most often with multiple DNS server addresses are configured, use Network Monitor analyzes the network traffic sent by customers. So, do you? DNS server will know exactly what they are? Try to speak with, and you can focus your troubleshooting efforts first.

Another common problem is the root of multi-homed servers. Unless otherwise, that server’s IP addresses registered with DNS. Some of these locations may be associated with network interfaces that are not accessible to all clients. The result is that some customers have access to the server and other is won? T. You can also customers, the access switch and not, especially when round-robin DNS is enabled on your DNS server. Round Robin can switch between an IP address, an accessible and inaccessible are alternated, thus temporarily problems for customers.

can cause problems during replication
replication problems from time to time problems in Active Directory (AD)-integrated DNS zones cause. Ensure that the AD replication is working properly to begin with. Customers require different DNS servers can get different answers if the two servers paradise? T nor convergence.
If the replication latency is a problem for your DNS zones to upgrade to Windows Server 2003. In Windows Server 2003 DNS zone is stored in a partition AD, and you can use domain controllers contain a copy of the score. By limiting the score, only the domain controllers as DNS servers, you? Ll force a new replication topology to be generated for the partition. The result is fewer servers to replicate information. Thus, the replication will be able to produce faster, so the different copies of the score converge faster and reduce the problems caused by replication latency.

occur protocol problems
Another problem, if your network is likely that the DNA-User Datagram Protocol (UDP) and port 53 blocked access used for the transmission network Control Protocol (TCP) port 53 The DNS specification requires DNS in order to use the UDP transport protocol connection, but only for small queries. Sticky topics? or, more precisely, the answers to more questions? t match won? in a single UDP packet can be split into several TCP packets instead. This switch can cause major problems for TCP in your network because some DNS queries are working correctly, and others will simply expire.

If you? Not sure that this fact relates to your problem, try to collect and use Network Monitor DNStraffic both sides of the firewall. Unless you’re the same traffic on both sides of the firewall, the firewall is blocking DNS traffic appeared to press the most likely answer. To be sure, I recommend opening your network to incoming DNS traffic over TCP and UDP ports 53

DNS Server