| BOOL TraceRoute( |
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LPCTSTR lpszHostName, |
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UINT nMaxHops, |
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DWORD dwTimeout |
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The TraceRoute method sends a series of ICMP echo datagrams
to trace the route taken from the local system to the remote
host.
Parameters
- lpszHostName
- A pointer to a string which specifies the fully
qualified domain name of the remote host, or the IP address in
dotted notation.
- nMaxHops
- An unsigned integer which specifies the maximum number of
routers the datagram will be forwarded through (the number of hops)
to the remote host. The minimum value is 1 and the maximum value is
255. It is recommended that most applications specify a value of at
least 30.
- dwTimeout
- An unsigned integer which specifies the number of milliseconds
the method will wait for a response to an echo datagram.
Return Value
If the method succeeds, the return value is non-zero. If the
method fails, the return value is zero. To get extended error
information, call GetLastError.
Remarks
The TraceRoute method sends a series of ICMP echo datagrams
to the specified host, adjusting the time-to-live value to determine
the intermediate hosts that route the packet. Use the
GetFirstHost and GetNextHost methods to enumerate the
hosts returned by the method.
It is important to note that the failure of an intermediate host
to respond to an ICMP echo datagram may not indicate a problem with
the remote system. Systems can 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.
Example
BOOL bResult = pClient->TraceRoute(strAddress);
if (bResult)
{
ICMPTRACE icmpTrace;
bResult = pClient->GetFirstHost(icmpTrace);
while (bResult)
{
// The icmpTrace structure contains information about the
// intermediate host in the traceroute
CString strHostName;
pClient->ResolveAddress(icmpTrace.dwHostAddress, strHostName);
bResult = pClient->GetNextHost(icmpTrace);
}
}
Requirements
Minimum Desktop Platform: Windows 7 Service Pack 1
Minimum Server Platform: Windows Server 2008 R2 Service Pack 1
Header File: cstools11.h
Import Library: csicmv11.lib
See Also
Echo,
GetFirstHost,
GetNextHost,
ResolveAddress
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