System.Security.Util.SiteString.IsLegalDNSChar C# (CSharp) Method

        private static bool IsLegalDNSChar(char c)
        {
            if ((c >= 'a' && c <= 'z') ||
                (c >= 'A' && c <= 'Z') ||
                (c >= '0' && c <= '9') ||
                (c == '-'))
                return true;
            else
                return false;
        }
        private static bool IsNetbiosSplChar(char c)

 // Token: 0x06002B10 RID: 11024 RVA: 0x0009FD88 File Offset: 0x0009DF88
 private static bool AllLegalCharacters(string str)
 {
     foreach (char c in str)
     {
         if (!SiteString.IsLegalDNSChar(c) && !SiteString.IsNetbiosSplChar(c))
         {
             return(false);
         }
     }
     return(true);
 }