DNS Class

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The DNS class is used to query DNS for record information.

Syntax

DNS

Remarks

The DNS class queries a DNS server for records as specified in RFC 1035 and other relevant RFCs. The class property QueryType indicates the record to be queried. Calling Query will initiate the query.

Once the query is complete, a single Response event will fire and the record properties will be filled. StatusCode is the server's success or fail code, and Status is a standard string interpretation of the code.

The records are contained in the Records properties. The programming interface is designed to allow a full walk of the records in the DNS response, including provisions for handling new record types.

The class operates synchronously by default (i.e., it waits for a response before returning control to the caller); however, the class also may operate asynchronously (i.e., return control immediately), by setting Timeout to 0. Please see the Timeout property for more information.

Property List

The following is the full list of the properties of the class with short descriptions. Click on the links for further details.

Method List

The following is the full list of the methods of the class with short descriptions. Click on the links for further details.

Event List

The following is the full list of the events fired by the class with short descriptions. Click on the links for further details.

Config Settings

The following is a list of config settings for the class with short descriptions. Click on the links for further details.

DNSPort Property (DNS Class)

This is the port to connect to on the DNS server.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int GetDNSPort();
int SetDNSPort(int iDNSPort);

Unicode (Windows)
INT GetDNSPort();
INT SetDNSPort(INT iDNSPort);

int ipworks_dns_getdnsport(void* lpObj);
int ipworks_dns_setdnsport(void* lpObj, int iDNSPort);

int GetDNSPort();
int SetDNSPort(int iDNSPort);

Default Value

53

Remarks

This property contains the port to connect to on the DNS server. A valid port number (a value between 1 and 65535) is required for the connection to take place. The property must be set before a connection is attempted and cannot be changed once a connection is established. Any attempt to change this property while connected will fail with an error.

This property is not available at design time.

Data Type

Integer

DNSServer Property (DNS Class)

This is the address of the DNS server.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
char* GetDNSServer();
int SetDNSServer(const char* lpszDNSServer);

Unicode (Windows)
LPWSTR GetDNSServer();
INT SetDNSServer(LPCWSTR lpszDNSServer);

char* ipworks_dns_getdnsserver(void* lpObj);
int ipworks_dns_setdnsserver(void* lpObj, const char* lpszDNSServer);

QString GetDNSServer();
int SetDNSServer(QString qsDNSServer);

Default Value

""

Remarks

This property contains the address of the DNS server. The class attempts to find the default DNS server for the machine where it is installed, and provide it in the DNSServer property. You may change it to any particular DNS server you want to query. While any internet host running a DNS service will suffice, it is preferable to use either the DNS server for your network or the DNS server for the domain that you are querying.

If the class cannot determine the default DNS server address, the property value will be an empty string.

Note: Automatic discovery of the default DNS server is not supported in the Java edition.

This property is not available at design time.

Data Type

String

Idle Property (DNS Class)

The current status of the class.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int GetIdle();

Unicode (Windows)
BOOL GetIdle();

int ipworks_dns_getidle(void* lpObj);

bool GetIdle();

Default Value

TRUE

Remarks

Idle will be False if the component is currently busy (communicating and/or waiting for an answer), and True at all other times.

This property is read-only.

Data Type

Boolean

LocalHost Property (DNS Class)

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
char* GetLocalHost();
int SetLocalHost(const char* lpszLocalHost);

Unicode (Windows)
LPWSTR GetLocalHost();
INT SetLocalHost(LPCWSTR lpszLocalHost);

char* ipworks_dns_getlocalhost(void* lpObj);
int ipworks_dns_setlocalhost(void* lpObj, const char* lpszLocalHost);

QString GetLocalHost();
int SetLocalHost(QString qsLocalHost);

Default Value

""

Remarks

The LocalHost property contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multi-homed hosts (machines with more than one IP interface) setting LocalHost to the value of an interface will make the class initiate connections (or accept in the case of server classs) only through that interface.

If the class is connected, the LocalHost property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multi-homed hosts (machines with more than one IP interface).

NOTE: LocalHost is not persistent. You must always set it in code, and never in the property window.

Data Type

String

Protocol Property (DNS Class)

This protocol is used for the DNS request.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int GetProtocol();
int SetProtocol(int iProtocol);

Unicode (Windows)
INT GetProtocol();
INT SetProtocol(INT iProtocol);

PT_UDP(0), 
PT_TCP(1), 
PT_TLS(2), 
PT_HTTPS(3)

int ipworks_dns_getprotocol(void* lpObj);
int ipworks_dns_setprotocol(void* lpObj, int iProtocol);

int GetProtocol();
int SetProtocol(int iProtocol);

Default Value

0

Remarks

This property specifies the protocol used for the DNS request when Query is called. Possible values include the following:

Data Type

Integer

QueryType Property (DNS Class)

This is the type of record to query.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int GetQueryType();
int SetQueryType(int iQueryType);

Unicode (Windows)
INT GetQueryType();
INT SetQueryType(INT iQueryType);

QT_ADDRESS(1), 
QT_NS(2), 
QT_MD(3), 
QT_MF(4), 
QT_CNAME(5), 
QT_SOA(6), 
QT_MAIL_BOX(7), 
QT_MAIL_GROUP(8), 
QT_MR(9), 
QT_NULL(10), 
QT_WKS(11), 
QT_POINTER(12), 
QT_HOST_INFO(13), 
QT_MAIL_INFO(14), 
QT_MX(15), 
QT_TEXT(16), 
QT_RP(17), 
QT_AFSDB(18), 
QT_X25(19), 
QT_ISDN(20), 
QT_RT(21), 
QT_AAAA(28), 
QT_SRV(33), 
QT_NAPTR(35), 
QT_CERT(37), 
QT_REV_LOOKUP(100)

int ipworks_dns_getquerytype(void* lpObj);
int ipworks_dns_setquerytype(void* lpObj, int iQueryType);

int GetQueryType();
int SetQueryType(int iQueryType);

Default Value

1

Remarks

Before a query is attempted, this property must be set to the desired record type. The records are defined as follows:

This property is not available at design time.

Data Type

Integer

RecordCount Property (DNS Class)

The number of records in the Record arrays.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int GetRecordCount();

Unicode (Windows)
INT GetRecordCount();

int ipworks_dns_getrecordcount(void* lpObj);

int GetRecordCount();

Default Value

0

Remarks

This property controls the size of the following arrays:

• RecordData
• RecordDomain
• RecordFieldCount
• RecordFieldIndex
• RecordFieldName
• RecordFieldValue
• RecordTTL
• RecordType
• RecordTypeName

The array indices start at 0 and end at RecordCount - 1.

This property is read-only and not available at design time.

Data Type

Integer

RecordDomain Property (DNS Class)

This property contains the domain name associated with the selected response record, at RecordIndex .

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
char* GetRecordDomain(int iRecordIndex);

Unicode (Windows)
LPWSTR GetRecordDomain(INT iRecordIndex);

char* ipworks_dns_getrecorddomain(void* lpObj, int recordindex);

QString GetRecordDomain(int iRecordIndex);

Default Value

""

Remarks

This property contains the domain name associated with the selected response record, at RecordIndex.

The RecordIndex parameter specifies the index of the item in the array. The size of the array is controlled by the RecordCount property.

This property is read-only and not available at design time.

Data Type

String

RecordFieldCount Property (DNS Class)

This property contains the number of properties in the current record.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int GetRecordFieldCount(int iRecordIndex);

Unicode (Windows)
INT GetRecordFieldCount(INT iRecordIndex);

int ipworks_dns_getrecordfieldcount(void* lpObj, int recordindex);

int GetRecordFieldCount(int iRecordIndex);

Default Value

0

Remarks

This property contains the number of properties in the current record.

After a successful query, the field values for each record will be provided in the Records properties.

To retrieve a particular field value for a record, first set RecordFieldIndex to a valid response field index and then query records collection for the value of that field.

The RecordIndex parameter specifies the index of the item in the array. The size of the array is controlled by the RecordCount property.

This property is read-only and not available at design time.

Data Type

Integer

RecordFieldIndex Property (DNS Class)

This property contains the index of the selected property of the current record.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int GetRecordFieldIndex(int iRecordIndex);
int SetRecordFieldIndex(int iRecordIndex, int iRecordFieldIndex);

Unicode (Windows)
INT GetRecordFieldIndex(INT iRecordIndex);
INT SetRecordFieldIndex(INT iRecordIndex, INT iRecordFieldIndex);

int ipworks_dns_getrecordfieldindex(void* lpObj, int recordindex);
int ipworks_dns_setrecordfieldindex(void* lpObj, int recordindex, int iRecordFieldIndex);

int GetRecordFieldIndex(int iRecordIndex);
int SetRecordFieldIndex(int iRecordIndex, int iRecordFieldIndex);

Default Value

1

Remarks

This property contains the index of the selected property of the current record. RecordFieldIndex valid values are from 0 to (RecordFieldCount -1).

After a successful query, the field values for each record will be provided in the Records properties.

To retrieve a particular field value for a record, first set RecordFieldIndex to a valid response field index and then query records collection for the value of that field.

The RecordIndex parameter specifies the index of the item in the array. The size of the array is controlled by the RecordCount property.

This property is not available at design time.

Data Type

Integer

RecordFieldName Property (DNS Class)

This property contains the name of the property selected by FieldIndex .

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
char* GetRecordFieldName(int iRecordIndex);

Unicode (Windows)
LPWSTR GetRecordFieldName(INT iRecordIndex);

char* ipworks_dns_getrecordfieldname(void* lpObj, int recordindex);

QString GetRecordFieldName(int iRecordIndex);

Default Value

"0"

Remarks

This property contains the name of the field selected by RecordFieldIndex. Field names are different depending on the record type. For example, an MX record type will contain two properties: PREFERENCE and EXCHANGE, but an SOA record type contains seven properties.

Field names:

The RecordIndex parameter specifies the index of the item in the array. The size of the array is controlled by the RecordCount property.

This property is read-only and not available at design time.

Data Type

String

RecordFieldValue Property (DNS Class)

This property contains the value of the property selected by FieldIndex .

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int GetRecordFieldValue(int iRecordIndex, char* &lpRecordFieldValue, int &lenRecordFieldValue);

Unicode (Windows)
INT GetRecordFieldValue(INT iRecordIndex, LPSTR &lpRecordFieldValue, INT &lenRecordFieldValue);

int ipworks_dns_getrecordfieldvalue(void* lpObj, int recordindex, char** lpRecordFieldValue, int* lenRecordFieldValue);

QByteArray GetRecordFieldValue(int iRecordIndex);

Default Value

""

Remarks

This property contains the value of the field selected by RecordFieldIndex.

After a successful query, the field values for each record will be provided in the Records properties.

To retrieve a particular field value for a record, first set RecordFieldIndex to a valid response field index and then query records collection for the value of that field.

The RecordIndex parameter specifies the index of the item in the array. The size of the array is controlled by the RecordCount property.

This property is read-only and not available at design time.

Data Type

Binary String

RecordData Property (DNS Class)

This property contains the full record data as received from the DNS server.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int GetRecordData(int iRecordIndex, char* &lpRecordData, int &lenRecordData);

Unicode (Windows)
INT GetRecordData(INT iRecordIndex, LPSTR &lpRecordData, INT &lenRecordData);

int ipworks_dns_getrecorddata(void* lpObj, int recordindex, char** lpRecordData, int* lenRecordData);

QByteArray GetRecordData(int iRecordIndex);

Default Value

""

Remarks

This property contains the full record data as received from the DNS server.

After a successful query, the field values for each record will be provided in the Records properties.

To retrieve a particular field value for a record, first set RecordFieldIndex to a valid response field index and then query records collection for the value of that field.

The RecordIndex parameter specifies the index of the item in the array. The size of the array is controlled by the RecordCount property.

This property is read-only and not available at design time.

Data Type

Binary String

RecordType Property (DNS Class)

This property contains the record type.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int GetRecordType(int iRecordIndex);

Unicode (Windows)
INT GetRecordType(INT iRecordIndex);

RT_ADDRESS(1), 
RT_NS(2), 
RT_MD(3), 
RT_MF(4), 
RT_CNAME(5), 
RT_SOA(6), 
RT_MAIL_BOX(7), 
RT_MAIL_GROUP(8), 
RT_MR(9), 
RT_NULL(10), 
RT_WKS(11), 
RT_POINTER(12), 
RT_HOST_INFO(13), 
RT_MAIL_INFO(14), 
RT_MX(15), 
RT_TEXT(16), 
RT_RP(17), 
RT_AFSDB(18), 
RT_X25(19), 
RT_ISDN(20), 
RT_RT(21), 
RT_AAAA(28), 
RT_SRV(33), 
RT_NAPTR(35)

int ipworks_dns_getrecordtype(void* lpObj, int recordindex);

int GetRecordType(int iRecordIndex);

Default Value

1

Remarks

This property contains the record type.

Record types correspond to QueryType and are defined as follows:

The RecordIndex parameter specifies the index of the item in the array. The size of the array is controlled by the RecordCount property.

This property is read-only and not available at design time.

Data Type

Integer

RecordTypeName Property (DNS Class)

This property contains the string representation of the current record type defined by RecordType .

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
char* GetRecordTypeName(int iRecordIndex);

Unicode (Windows)
LPWSTR GetRecordTypeName(INT iRecordIndex);

char* ipworks_dns_getrecordtypename(void* lpObj, int recordindex);

QString GetRecordTypeName(int iRecordIndex);

Default Value

""

Remarks

This property contains the string representation of the current record type defined by RecordType.

The RecordIndex parameter specifies the index of the item in the array. The size of the array is controlled by the RecordCount property.

This property is read-only and not available at design time.

Data Type

String

RecordTTL Property (DNS Class)

This property contains the record Time to Live (TTL) value.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int GetRecordTTL(int iRecordIndex);

Unicode (Windows)
INT GetRecordTTL(INT iRecordIndex);

int ipworks_dns_getrecordttl(void* lpObj, int recordindex);

int GetRecordTTL(int iRecordIndex);

Default Value

0

Remarks

This property contains the record Time to Live (TTL) value. The TTL specifies the time interval in seconds that the record is valid, or the time interval that the record can be cached before the DNS server should be queried again.

The RecordIndex parameter specifies the index of the item in the array. The size of the array is controlled by the RecordCount property.

This property is read-only and not available at design time.

Data Type

Integer

RecordSource Property (DNS Class)

The source of records provided in the Records properties.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int GetRecordSource();
int SetRecordSource(int iRecordSource);

Unicode (Windows)
INT GetRecordSource();
INT SetRecordSource(INT iRecordSource);

RS_ANSWER_SECTION(0), 
RS_NAME_SERVER_SECTION(1), 
RS_ADDITIONAL_RECORDS_SECTION(2)

int ipworks_dns_getrecordsource(void* lpObj);
int ipworks_dns_setrecordsource(void* lpObj, int iRecordSource);

int GetRecordSource();
int SetRecordSource(int iRecordSource);

Default Value

0

Remarks

This property contains the source of records provided in the Records properties and can have one of the following values:

This property is not available at design time.

Data Type

Integer

Recursive Property (DNS Class)

This determines whether to ask the DNSServer to recursively query other servers.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int GetRecursive();
int SetRecursive(int bRecursive);

Unicode (Windows)
BOOL GetRecursive();
INT SetRecursive(BOOL bRecursive);

int ipworks_dns_getrecursive(void* lpObj);
int ipworks_dns_setrecursive(void* lpObj, int bRecursive);

bool GetRecursive();
int SetRecursive(bool bRecursive);

Default Value

TRUE

Remarks

If this property is True, the component will tell the DNS server to perform the query recursively. This means that if the DNS server does not have information about the domain being queried, it will send the request to another DNS server.

This property is not available at design time.

Data Type

Boolean

RequestId Property (DNS Class)

This is the Id of the current DNS request.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int GetRequestId();
int SetRequestId(int iRequestId);

Unicode (Windows)
INT GetRequestId();
INT SetRequestId(INT iRequestId);

int ipworks_dns_getrequestid(void* lpObj);
int ipworks_dns_setrequestid(void* lpObj, int iRequestId);

int GetRequestId();
int SetRequestId(int iRequestId);

Default Value

1

Remarks

This property is the identifier of the request that generated the current response values. Each time the class makes a DNS query, it generates a unique request identifier to track the response.

If a custom value is needed for RequestId, the property must be set before sending a request. The class increments RequestId automatically after sending each request.

Note: The class fails with an error when a value that is not between 1 and 32,767 is specified.

This property is not available at design time.

Data Type

Integer

Status Property (DNS Class)

This is a standard string interpretation of StatusCode .

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
char* GetStatus();

Unicode (Windows)
LPWSTR GetStatus();

char* ipworks_dns_getstatus(void* lpObj);

QString GetStatus();

Default Value

""

Remarks

This property contains a standard string interpretation of StatusCode. For a list of valid error codes and their descriptions, please see the Error Codes section.

This property is read-only and not available at design time.

Data Type

String

StatusCode Property (DNS Class)

This contains the success or error code for the DNS query.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int GetStatusCode();

Unicode (Windows)
INT GetStatusCode();

int ipworks_dns_getstatuscode(void* lpObj);

int GetStatusCode();

Default Value

0

Remarks

This property contains the success or error code for the DNS query. For a list of valid error codes and their descriptions, please see the Error Codes section.

This property is read-only and not available at design time.

Data Type

Integer

Timeout Property (DNS Class)

A timeout for the class.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int GetTimeout();
int SetTimeout(int iTimeout);

Unicode (Windows)
INT GetTimeout();
INT SetTimeout(INT iTimeout);

int ipworks_dns_gettimeout(void* lpObj);
int ipworks_dns_settimeout(void* lpObj, int iTimeout);

int GetTimeout();
int SetTimeout(int iTimeout);

Default Value

60

Remarks

If the Timeout property is set to 0, all operations return immediately, potentially failing with a WOULDBLOCK error if data cannot be sent immediately.

If Timeout is set to a positive value, data is sent in a blocking manner and the class will wait for the operation to complete before returning control. The class will handle any potential WOULDBLOCK errors internally and automatically retry the operation for a maximum of Timeout seconds.

The class will use DoEvents to enter an efficient wait loop during any potential waiting period, making sure that all system events are processed immediately as they arrive. This ensures that the host application does not "freeze" and remains responsive.

If Timeout expires, and the operation is not yet complete, the class fails with an error.

Please note that by default, all timeouts are inactivity timeouts, i.e. the timeout period is extended by Timeout seconds when any amount of data is successfully sent or received.

The default value for the Timeout property is 60 seconds.

Data Type

Integer

Config Method (DNS Class)

Sets or retrieves a configuration setting.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
char* Config(const char* lpszConfigurationString);

Unicode (Windows)
LPWSTR Config(LPCWSTR lpszConfigurationString);

char* ipworks_dns_config(void* lpObj, const char* lpszConfigurationString);

QString Config(const QString& qsConfigurationString);

Remarks

Config is a generic method available in every class. It is used to set and retrieve configuration settings for the class.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

Error Handling (C++)

This method returns a String value; after it returns, call the GetLastErrorCode() method to obtain its result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message.

DoEvents Method (DNS Class)

Processes events from the internal message queue.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int DoEvents();

Unicode (Windows)
INT DoEvents();

int ipworks_dns_doevents(void* lpObj);

int DoEvents();

Remarks

When DoEvents is called, the class processes any available events. If no events are available, it waits for a preset period of time, and then returns.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

GetFieldValue Method (DNS Class)

This gets the value of the field indicated from a record.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
char* GetFieldValue(int iRecordIndex, const char* lpszFieldName);

Unicode (Windows)
LPWSTR GetFieldValue(INT iRecordIndex, LPCWSTR lpszFieldName);

char* ipworks_dns_getfieldvalue(void* lpObj, int iRecordIndex, const char* lpszFieldName);

QString GetFieldValue(int iRecordIndex, const QString& qsFieldName);

Remarks

This method will get the value of the DNS record field specified by FieldName from the DNS record at RecordIndex. If no such field exists for that record type, the component fails with an error.

Error Handling (C++)

This method returns a String value; after it returns, call the GetLastErrorCode() method to obtain its result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message.

Interrupt Method (DNS Class)

Interrupt the current method.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int Interrupt();

Unicode (Windows)
INT Interrupt();

int ipworks_dns_interrupt(void* lpObj);

int Interrupt();

Remarks

If there is no method in progress, Interrupt simply returns, doing nothing.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

Query Method (DNS Class)

This method queries a domain.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int Query(const char* lpszDomain);

Unicode (Windows)
INT Query(LPCWSTR lpszDomain);

int ipworks_dns_query(void* lpObj, const char* lpszDomain);

int Query(const QString& qsDomain);

Remarks

This method will query the host Domain for any records of the type in QueryType. After the query, RequestId is the identifier corresponding to the request. Once the query is complete, a single Response event will fire. The following properties will contain the results:

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

Reset Method (DNS Class)

Reset the class.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int Reset();

Unicode (Windows)
INT Reset();

int ipworks_dns_reset(void* lpObj);

int Reset();

Remarks

This method will reset the class's properties to their default values.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

Error Event (DNS Class)

Fired when information is available about errors during data delivery.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
virtual int FireError(DNSErrorEventParams *e);

typedef struct {
  int ErrorCode;
  const char *Description;
  int reserved;
} DNSErrorEventParams;


Unicode (Windows)
virtual INT FireError(DNSErrorEventParams *e);

typedef struct {
  INT ErrorCode;
  LPCWSTR Description;
  INT reserved;
} DNSErrorEventParams;

#define EID_DNS_ERROR 1

virtual INT IPWORKS_CALL FireError(INT &iErrorCode, LPSTR &lpszDescription);

class DNSErrorEventParams {
public:
  int ErrorCode();

  const QString &Description();

  int EventRetVal();
  void SetEventRetVal(int iRetVal);
};

// To handle, connect one or more slots to this signal.
void Error(DNSErrorEventParams *e);

// Or, subclass DNS and override this emitter function.
virtual int FireError(DNSErrorEventParams *e) {...}

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the class fails with an error.

The ErrorCode parameter contains an error code, and the Description parameter contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

Log Event (DNS Class)

This event fires once for each log message.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
virtual int FireLog(DNSLogEventParams *e);

typedef struct {
  int LogLevel;
  const char *Message;
  const char *LogType;
  int reserved;
} DNSLogEventParams;


Unicode (Windows)
virtual INT FireLog(DNSLogEventParams *e);

typedef struct {
  INT LogLevel;
  LPCWSTR Message;
  LPCWSTR LogType;
  INT reserved;
} DNSLogEventParams;

#define EID_DNS_LOG 2

virtual INT IPWORKS_CALL FireLog(INT &iLogLevel, LPSTR &lpszMessage, LPSTR &lpszLogType);

class DNSLogEventParams {
public:
  int LogLevel();

  const QString &Message();

  const QString &LogType();

  int EventRetVal();
  void SetEventRetVal(int iRetVal);
};

// To handle, connect one or more slots to this signal.
void Log(DNSLogEventParams *e);

// Or, subclass DNS and override this emitter function.
virtual int FireLog(DNSLogEventParams *e) {...}

Remarks

This event fires once for each log message generated by the class. The verbosity is controlled by the LogLevel setting.

LogLevel indicates the level of message. Possible values are as follows:

The value 1 (Info) logs basic information, including the URL, HTTP version, and status details.

The value 2 (Verbose) logs additional information about the request and response.

The value 3 (Debug) logs the headers and body for both the request and response, as well as additional debug information (if any).

Message is the log entry.

LogType identifies the type of log entry. Possible values are as follows:

• "Info"
• "RequestHeaders"
• "ResponseHeaders"
• "RequestBody"
• "ResponseBody"
• "ProxyRequest"
• "ProxyResponse"
• "FirewallRequest"
• "FirewallResponse"

Response Event (DNS Class)

This event fires after a DNS query.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
virtual int FireResponse(DNSResponseEventParams *e);

typedef struct {
  int RequestId;
  const char *Domain;
  int StatusCode;
  const char *Description;
  int Authoritative;
  int reserved;
} DNSResponseEventParams;


Unicode (Windows)
virtual INT FireResponse(DNSResponseEventParams *e);

typedef struct {
  INT RequestId;
  LPCWSTR Domain;
  INT StatusCode;
  LPCWSTR Description;
  BOOL Authoritative;
  INT reserved;
} DNSResponseEventParams;

#define EID_DNS_RESPONSE 3

virtual INT IPWORKS_CALL FireResponse(INT &iRequestId, LPSTR &lpszDomain, INT &iStatusCode, LPSTR &lpszDescription, BOOL &bAuthoritative);

class DNSResponseEventParams {
public:
  int RequestId();

  const QString &Domain();

  int StatusCode();

  const QString &Description();

  bool Authoritative();

  int EventRetVal();
  void SetEventRetVal(int iRetVal);
};

// To handle, connect one or more slots to this signal.
void Response(DNSResponseEventParams *e);

// Or, subclass DNS and override this emitter function.
virtual int FireResponse(DNSResponseEventParams *e) {...}

Remarks

The Response event will fire after a call to Query. The RequestId parameter contains the request Id associated with the original query. Domain is the domain of the query. The Authoritative parameter is true if the response is from an authoritative name server. If there is an error returned by the server, StatusCode and Description provide them.

Once the query is complete, a single Response event will fire. The following properties will contain the results:

SSLServerAuthentication Event (DNS Class)

This event fires when connecting to the server.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
virtual int FireSSLServerAuthentication(DNSSSLServerAuthenticationEventParams *e);

typedef struct {
  const char *RemoteAddress;
  int RemotePort;
  const char *CertEncoded;
  int lenCertEncoded;
  const char *CertSubject;
  const char *CertIssuer;
  const char *Status;
  int Accept;
  int reserved;
} DNSSSLServerAuthenticationEventParams;


Unicode (Windows)
virtual INT FireSSLServerAuthentication(DNSSSLServerAuthenticationEventParams *e);

typedef struct {
  LPCWSTR RemoteAddress;
  INT RemotePort;
  LPCSTR CertEncoded;
  INT lenCertEncoded;
  LPCWSTR CertSubject;
  LPCWSTR CertIssuer;
  LPCWSTR Status;
  BOOL Accept;
  INT reserved;
} DNSSSLServerAuthenticationEventParams;

#define EID_DNS_SSLSERVERAUTHENTICATION 4

virtual INT IPWORKS_CALL FireSSLServerAuthentication(LPSTR &lpszRemoteAddress, INT &iRemotePort, LPSTR &lpCertEncoded, INT &lenCertEncoded, LPSTR &lpszCertSubject, LPSTR &lpszCertIssuer, LPSTR &lpszStatus, BOOL &bAccept);

class DNSSSLServerAuthenticationEventParams {
public:
  const QString &RemoteAddress();

  int RemotePort();

  const QByteArray &CertEncoded();

  const QString &CertSubject();

  const QString &CertIssuer();

  const QString &Status();

  bool Accept();
  void SetAccept(bool bAccept);

  int EventRetVal();
  void SetEventRetVal(int iRetVal);
};

// To handle, connect one or more slots to this signal.
void SSLServerAuthentication(DNSSSLServerAuthenticationEventParams *e);

// Or, subclass DNS and override this emitter function.
virtual int FireSSLServerAuthentication(DNSSSLServerAuthenticationEventParams *e) {...}

Remarks

This event allows the client to decide whether or not to continue with the connection process. The Accept parameter recommends whether to continue or close the connection. This is just a suggestion: application software must use its own logic to determine whether or not to continue.

When Accept is False, Status shows why the verification failed (otherwise, Status contains the string "OK"). If the client decides to continue, you can override and accept the certificate by setting the Accept parameter to True.

RemoteAddress is the IP address of the server.

RemotePort is the source port of the server.

CertEncoded is the Base64-encoded certificate presented by the server.

CertSubject is the subject of the certificate presented by the server.

CertIssuer is the subject of the issuer of the certificate presented by the server.

Status is the status of the certificate.

Accept defines whether the certificate is accepted.

SSLStatus Event (DNS Class)

This shows the progress of the secure connection.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
virtual int FireSSLStatus(DNSSSLStatusEventParams *e);

typedef struct {
  const char *RemoteAddress;
  int RemotePort;
  const char *Message;
  int reserved;
} DNSSSLStatusEventParams;


Unicode (Windows)
virtual INT FireSSLStatus(DNSSSLStatusEventParams *e);

typedef struct {
  LPCWSTR RemoteAddress;
  INT RemotePort;
  LPCWSTR Message;
  INT reserved;
} DNSSSLStatusEventParams;

#define EID_DNS_SSLSTATUS 5

virtual INT IPWORKS_CALL FireSSLStatus(LPSTR &lpszRemoteAddress, INT &iRemotePort, LPSTR &lpszMessage);

class DNSSSLStatusEventParams {
public:
  const QString &RemoteAddress();

  int RemotePort();

  const QString &Message();

  int EventRetVal();
  void SetEventRetVal(int iRetVal);
};

// To handle, connect one or more slots to this signal.
void SSLStatus(DNSSSLStatusEventParams *e);

// Or, subclass DNS and override this emitter function.
virtual int FireSSLStatus(DNSSSLStatusEventParams *e) {...}

Remarks

The event is fired for informational and logging purposes only. It is used to track the progress of the connection.

RemoteAddress is the IP address of the remote machine.

RemotePort is the port of the remote machine.

Message is the log message.

Config Settings (DNS Class)

DNS Config Settings

UDP Config Settings

Socket Config Settings

Base Config Settings

Trappable Errors (DNS Class)

Error Handling (C++)

Call the GetLastErrorCode() method to obtain the last called method's result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. Known error codes are listed below. If an error occurs, the GetLastError() method can be called to retrieve the associated error message.

DNS Errors

The class may also return one of the following error codes, which are inherited from other classes.

UDP Errors

SSL Errors

TCP/IP Errors