aliasはキーワード

そうかー、aliasはキーワードだったのか。最初からエラーメッセージをちゃんと読んでいればよかったんだけどねえ。
というわけでIPAddressをチェックするサンプル。

Option Explicit

Option Strict
Imports System

Imports System.Net

Imports System.Net.Sockets
Class hoge
    Shared Sub Main(ByVal CmdArgs() As String)

        Dim strArgs As String
        For Each strArgs In CmdArgs

            Console.WriteLine(strArgs & ": ")

            PrintHostInfo(strArgs)

        Next
        Try

            Console.WriteLine("Local Host:")

            Dim localHostName As String = Dns.GetHostName()

            Console.WriteLine("    Host Name:       " & localHostName)

            PrintHostInfo(localHostName)

        Catch ex As Exception

            Console.WriteLine("    Unable to resolve local host")

        End Try

    End Sub
    Public Shared Function PrintHostInfo(ByVal host As String) As Integer

        Try

            Dim hostInfo As IPHostEntry

            Dim ipaddr As IPAddress

            Dim aliase As String
            hostInfo = Dns.Resolve(host)

            Console.WriteLine("    Canonical Name:  " & hostInfo.HostName)

            Console.Write("    IP Address:      ")

            For Each ipaddr In hostInfo.AddressList

                Console.Write(ipaddr.ToString() & " ")

            Next

            Console.WriteLine()
            Console.Write("    Aliases:         ")

            For Each aliase In hostInfo.Aliases

                Console.Write(aliase & " ")

            Next

            Console.WriteLine()
        Catch ex As Exception

            Console.WriteLine("    Unable to resolve host: " & host)

        End Try

    End Function

End Class

コンパイルオプションは以下のとおり。

> vbc /t:exe /out:ip.exe /debug+ /r:system.dll .vb

実行するとこんな感じ。

> ip.exe www.asahi.com

www.asahi.com:

    Canonical Name:  www.gslb.asahi.com

    IP Address:      220.173.169.165

    Aliases:         www.asahi.com

Local Host:

    Host Name:       Mikitty

    Canonical Name:  Mikitty

    IP Address:      192.xxx.xxx.xxx

    Aliases: