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Does DNS run over TCP?
DNS uses TCP for Zone transfer and UDP for name, and queries either regular (primary) or reverse. UDP can be used to exchange small information whereas TCP must be used to exchange information larger than 512 bytes.
How do I check if DNS is resolving Linux?
nslookup is a command-line administrative tool for testing and troubleshooting DNS servers (Domain Name Server). It is used to query specific DNS resource records (RR) as well. Most operating systems comes with built-in nslookup feature. This article demonstrates widely used nslookup command in detail.
How to troubleshoot DNS server that failed recursive query?
Add or connect to the DNS server that failed a recursive query. Right-click the server, and select Properties. Click Root Hints. Check for basic connectivity to the root servers. If root hints appear to be configured correctly, verify that the DNS server that’s used in a failed name resolution can ping the root servers by IP address.
What happens when a DNS server fails to respond?
For recursion to work successfully, all DNS servers that are used in the path of a recursive query must be able to respond and forward correct data. If they can’t, a recursive query can fail for any of the following reasons: The query times out before it can be completed. A server that’s used during the query fails to respond.
How can I find out what DNS server resolved my Name?
Simply type NSLOOKUP followed by the name of the host for which you want to test the name resolution. Windows will return the name and IP address of the DNS server that resolved the name (although the DNS server’s name is often listed as Unknown).
How can I tell which server is my Primary DNS server?
Examine the zone on the primary server (the server from which this server pulls zone transfers). You can determine which server is the primary server by examining the properties of the secondary zone in the DNS console. If the name is not correct on the primary server, go to step 4.