[RESOLVED] Fast Ping (non-blocking)

Hi there,

Could anyone help me with the Ping function?

I wish to Ping my whole local network "fast" as possible.

I tried with different API combinations like: inet_addr, GetRTTAndHopCount and IcmpSendEcho, but it's lagging and freezing the Form and it's too slow scanning the network.

My simple loop code example:

Code:

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Dim itCnt As Integer
Dim lgTimeOms as Long
Dim stIpRng As String
Dim stIpAddr As String

lgTimeOms = 100

stIpAddr = ""
stIpRng = "192.168.0."

For itCnt = 1 To 255
 stIpAddr = stIpRng + CStr(itCnt)
 If Ping(stIpAddr, lgTimeOms) = True Then
  List1.AddItem stIpAddr
 End If
 stIpAddr = ""
Next itCnt

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Note: I already did this all with ARP and it's working very fast, but unfortunately for me, I forgot that the ARP table will be cleared/lost after every computer restart, upssss.

Thank you,

Kind regards,
Viktor

have a look at the code posted by olaf
https://www.vbforums.com/showthread....=1#post4476707

i also have some similar code (no idea where it came from originally) that uses waitforsingleobject with a time out for each ip address
in either case som significant testing should be done to confirm correct results

Thank you, I already tried that solution, the problem is that the mentioned code only shows 3 of 10 IP addresses from the local network.

Any other suggestions or approach?

Quote:

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Originally Posted by beic

... the problem is that the mentioned code only shows 3 of 10 IP addresses from the local network.

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There's a Const within that function, which is currently at 100 (millisec).

Increasing this value to e.g. 500 (msec) could help, detecting the yet missing IPs.

Olaf

Quote:

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Originally Posted by Schmidt

Increasing this value to e.g. 500 (msec) could help, detecting the yet missing IPs.

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With 500ms is better, but would vary every time calling the function, with 1000ms is great, but again sometimes some IP addresses will be left out?

Quote:

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Originally Posted by beic

With 500ms is better, but would vary every time calling the function, ...

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That's normal...

Then perhaps calling the function "3-5 times in a loop" (then maybe with 350msec) will produce better results
(merging the IPs "not yet captured from previous inner-loop-results" into a final "target-collection").

Olaf

seems to be a far from perfect solution

Quote:

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Originally Posted by westconn1

seems to be a far from perfect solution

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ICMP itself is not a "reliable protocol" (the transport can fail for a whole lot of different reasons).

That's why a "ping-command" on the console is always starting a "whole sequence of pings" -
because "just a single ping" has a quite high probability, to not come back within a given time, due to "those multiple reasons".

<shrug>

Olaf

Quote:

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Originally Posted by Schmidt

That's normal...
Then perhaps calling the function "3-5 times in a loop" (then maybe with 350msec) will produce better results
(merging the IPs "not yet captured from previous inner-loop-results" into a final "target-collection").

---

But, I figured out something really good thing, I left out from your code the "Collection" part, only Ping left (one time loop needed of 1000ms).

So, after I realized that your Ping function with Echo Reply will recreate the ARP table on current computer and I could easily fetch data from it.

And now I got full network scan with IP, MAC Addresses and with Host Names under 4-7 seconds with Device Name + MAC Address Vendor parsing.

care to share your code. may help others in the future

Quote:

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Originally Posted by k_zeon

care to share your code. may help others in the future

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There is really nothing to share, you just combine these two codes together from the posts:

https://www.vbforums.com/showthread....=1#post4476707
https://www.vbforums.com/showthread....-the-ARP-table