Specifies the options that the DnsClient class supports.
This enumeration has a FlagsAttribute attribute that allows a bitwise combination of its member values.
The DnsClient class uses the DnsOptions enumeration to specify one or more options to be used when establishing a connection with a remote host. Multiple options may be specified if necessary.
| Member Name | Description | Value |
|---|---|---|
| optionDefault | The default client option. This is the same as specifying optionNone. | 0 |
| optionNone | No option specified. | 0 |
| optionPromote | Promotes the server that successfully completed the last query to the first server that will be used to resolve subsequent queries. This option can improve performance in some cases where one or more of the registered servers are non-responsive. This option takes precedence over the optionRotate option. | 1 |
| optionRotate | Enables a round-robin selection of nameservers when performing queries. Normally each nameserver is queried in the same order. This option rotates the available nameservers so a different server is used with each query. | 2 |
| optionAuthOnly | Require the answer from the nameserver to be authoritative, not from the server's cache. This option is included for future expansion as most servers do not support this feature and will ignore it. | 4 |
| optionPrimary | Queries are only accepted from the primary nameserver. This option is included for future expansion as most servers do not support this feature and will ignore it. | 8 |
| optionNoRecurse | Disable the sending of recursive queries to the nameserver. Specifying this option will disable the bit in the DNS request header that specifies recursion is desired. | 16 |
| optionNoSearch | Disable additional queries of higher domains in the search list if the host name cannot be resolved. If this option is specified, and the host name cannot be resolved using the local domain name an error is returned immediately. This option is ignored if no local domain has been specified or if the optionNoSuffix option has been specified. | 32 |
| optionNoSuffix | Disable additional queries using the local domain name if the host name is not a fully qualified domain name and cannot be resolved. This option is ignored if no local domain has been specified. | 64 |
| optionNoNameCheck | Disable checking the host name for invalid characters, such as the underscore and control characters. By default, host names are checked to ensure they're valid before submitting a query to the nameserver. | 128 |
| optionFreeThread | This option specifies that class methods may be called from any thread, and not only the thread that established the connection. Using this option disables certain internal safety checks that are made by the class and may result in unexpected behavior unless you ensure that access to the class instance is synchronized across multiple threads. | 524288 |
Namespace: SocketTools
Assembly: SocketTools.DnsClient (in SocketTools.DnsClient.dll)