DnsAutodetectOptions Enumeration

Provides options for selecting methods of automatic detection of the DNS servers registered in the system.

Namespace: MailBee.DnsMX
Assembly: MailBee.NET.45 (in MailBee.NET.45.dll) Version: 10.0.45.502

Syntax

[FlagsAttribute]
public enum DnsAutodetectOptions

<FlagsAttribute>
Public Enumeration DnsAutodetectOptions

Members

Member name	Value	Description
None	0	Do nothing.
ConfigFiles	1	Search DNS server definitions in "MailBee.DnsMX.DnsServerCollection" key of "appSettings" section of the config files (such as app.config, web.config, or machine.config), where the key value contains ";"-separated list of DNS servers in "IP Address,Priority" format. If the priority is omitted, the top (0) priority will be assigned to the DNS server.
NetInterface	2	Use System.Net.NetworkInformation.NetworkInterface class (not supported in .NET 1.1 and requires UnmanagedCode permission). The most accurate method, however.
Registry	4	Search DNS server definitions in Windows registry. Usually, the last resort. Requires less permissions than NetInterface but less accurate.
Wmi	8	Search DNS server definitions in WMI database.
RootServers	16	Use DNS servers with addresses "8.8.8.8" and "8.8.4.4". These servers are always available but they belong to Google, not to your company or your ISP.
AllowIPv6Servers	32	If set, IPv6 entries (if present) will appear in the list of autodetected servers. If not set, only IPv4 servers will be added.

Remarks

If multiple methods are specified, they are tried in the order their values increase until at least one DNS server definition is found.

To search WMI database (Wmi option), the application must have appropriate permissions to use System.Management.dll (which encapsulates System.Management namespace). For instance, web applications configured to run on "High" trust level have no permissions to access this assembly. In this case, Autodetect method will not find any DNS server records in WMI database. Changing trust level to "Full" eliminates the problem.

To use System.Net.NetworkInformation.NetworkInterface class (the best method available), "High" trust level might also require "Full" level.

Examples

This sample populates the collection of DNS servers with the servers defined in the config files (such as app.config, web.config, or machine.config). If it does not find any DNS server definitions in the config files, then Windows registry is searched. IPv6 servers are not allowed.

Copy

// To use the code below, import MailBee namespaces at the top of your code
using MailBee;
using MailBee.SmtpMail;
using MailBee.DnsMX;

// The actual code
Smtp smtp = new Smtp();
smtp.DnsServers.Autodetect(DnsAutodetectOptions.ConfigFiles | DnsAutodetectOptions.Registry);

// Example of XML config file settings which must be placed into <appSettings> section of the file
// (<appSettings> can also appear as <applicationSettings> in .NET 2.0).
// It defines 2 DNS servers with top (0) priority and 1 backup server with lower (1) priority
// (for 192.168.0.2 server, the priority is not specified and thus defaults to the top priority):

<add key="MailBee.DnsMX.DnsServerCollection" value="192.168.0.1,0;192.168.0.2;192.168.0.100,1"/>

' To use the code below, import MailBee namespaces at the top of your code
Imports MailBee
Imports MailBee.SmtpMail
Imports MailBee.DnsMX

' The actual code
Dim smtp As New Smtp 
smtp.DnsServers.Autodetect(DnsAutodetectOptions.ConfigFiles Or DnsAutodetectOptions.Registry) 

' Example of XML config file settings which must be placed into <appSettings> section of the file
' (<appSettings> can also appear as <applicationSettings> in .NET 2.0).
' It defines 2 DNS servers with top (0) priority and 1 backup server with lower (1) priority
' (for 192.168.0.2 server, the priority is not specified and thus defaults to the top priority):

<add key="MailBee.DnsMX.DnsServerCollection" value="192.168.0.1,0;192.168.0.2;192.168.0.100,1"/>

Reference

MailBee.DnsMX Namespace

MailBee.SmtpMailSmtp