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Send an ICMP echo datagram to the specified host.
Syntax
object.Echo( [RemoteHost], [Timeout],
[TimeToLive] )
Parameters
- RemoteHost
- A string which specifies the host name or IP address which the
ICMP echo datagram will be sent to. If this argument is omitted,
the value of the HostAddress property will be used. If the
HostAddress property has not been set, then the value of the
HostName property will be used as the default value.
- Timeout
- An integer value which specifies the number of milliseconds
until a blocking operation fails and the control returns an error.
If this argument is omitted, the value of the Timeout
property will be used as the default value.
- TimeToLive
- An integer value which specifies the time-to-live (TTL) value
for the ICMP echo datagram. If this argument is omitted, the value
of the TimeToLive property will be used as the default
value. For more information about how this is used, refer to the
TimeToLive property.
Return Value
A value of zero is returned if the operation was successful,
otherwise a non-zero error code is returned which indicates the cause
of the failure.
Remarks
The Echo method sends an ICMP echo datagram to the specified
host. The failure for a host to respond to an ICMP echo datagram may
not indicate a problem with the remote system. In some cases, a router
between the local and remote host may be malfunctioning or discarding
the datagrams. Systems can also be configured to specifically ignore
ICMP echo datagrams and not respond to them; this is often a security
measure to prevent certain kinds of Denial of Service attacks.
The ability to send ICMP datagrams may be restricted to users with
administrative privileges, depending on the policies and configuration
of the local system. If you are unable to send or receive any ICMP
datagrams, it is recommended that you check the firewall settings and
any third-party security software that could impact the normal
operation of this component.
See Also
Blocking Property,
HostAddress Property,
HostName Property,
Timeout Property,
TimeToLive Property,
TraceRoute Method,
OnEcho Event,
OnReply Event
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