Ping.SendAsync Method (String, Int32, Byte(), PingOptions, Object)


Asynchronously attempts to send an Internet Control Message Protocol (ICMP) echo message with the specified data buffer to the specified computer, and receive a corresponding ICMP echo reply message from that computer. This overload allows you to specify a time-out value for the operation and control fragmentation and Time-to-Live values for the ICMP packet.

Namespace:   System.Net.NetworkInformation
Assembly:  System (in System.dll)

<HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading := True)>
Public Sub SendAsync (
	hostNameOrAddress As String,
	timeout As Integer,
	buffer As Byte(),
	options As PingOptions,
	userToken As Object


Type: System.String

A String that identifies the computer that is the destination for the ICMP echo message. The value specified for this parameter can be a host name or a string representation of an IP address.

Type: System.Int32

A Byte array that contains data to be sent with the ICMP echo message and returned in the ICMP echo reply message. The array cannot contain more than 65,500 bytes.

Type: System.Byte()

An Int32 value that specifies the maximum number of milliseconds (after sending the echo message) to wait for the ICMP echo reply message.

Type: System.Net.NetworkInformation.PingOptions

A PingOptions object used to control fragmentation and Time-to-Live values for the ICMP echo message packet.

Type: System.Object

An object that is passed to the method invoked when the asynchronous operation completes.

Exception Condition

hostNameOrAddress is null or is an empty string ("").


buffer is null.


timeout is less than zero.


A call to SendAsync is in progress.


address is an IPv6 address and the local computer is running an operating system earlier than Windows 2000.


An exception was thrown while sending or receiving the ICMP messages. See the inner exception for the exact exception that was thrown.


hostNameOrAddress could not be resolved to a valid IP address.


This object has been disposed.


The size of buffer exceeds 65500 bytes.

The SendAsync method sends the Echo message asynchronously and, when the operation completes (successfully or unsuccessfully), returns the status to your application. Call the SendAsync method when your application must not block. Each call executes in a separate thread that is automatically allocated from the thread pool. When the asynchronous operation completes, it raises the PingCompleted event. Applications use a PingCompletedEventHandler delegate to specify the method that is called when SendAsync raises the event. You must add a PingCompletedEventHandler delegate to the event before calling SendAsync. The delegate's method receives a PingCompletedEventArgs object that contains a PingReply object that describes the result of the SendAsync call. The PingCompletedEventArgs object inherits the UserState property. This property contains the userToken object passed into the SendAsync call.

If your application should block while waiting for a reply, use the Send methods; these methods are synchronous.

If the ICMP echo reply message is not received within the time specified by the timeout parameter, the ICMP echo fails, and the Status property is set to TimedOut.


When specifying very small numbers for timeout, the Ping reply can be received even if timeout milliseconds have elapsed.

If the DontFragment property is true and the total packet size exceeds the maximum packet size that can be transmitted by one of the routing nodes between the local and remote computers, the ICMP echo request fails. When this happens, the Status is set to PacketTooBig.

Use the Ttl property to specify the maximum number of times the ICMP echo message can be forwarded before reaching its destination. If the packet does not reach its destination after being forwarded the specified number of times, the packet is discarded and the ICMP echo request fails. When this happens, the Status is set to TtlExpired.

Legacy Code Example

The following code example demonstrates how to call this method.

No code example is currently available or this language may not be supported.

To send an ICMP echo message.

Associated enumeration: Ping

.NET Framework
Available since 2.0
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