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that's it, is there a way to discover a network topology at level 3 or IP level, i mean, i want to build a program that maps the different networks that are reachable from mine and where the routers are. any ideas? thanks in advance ike

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Well, you should look at tools like OpenNMS which do automated discovery of your network configuration and services. There's lots of other ones out there, that just came to mind.

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you can use SNMP protocols to discover a lot of information on the network. A lot of tools free/commercial are already available for this. You mention you want to do this on your own so you have to look at the SNMP holy grail, I would start here

You could do basic level 3 work with readily available libraries. I would like to mention that in case you want to discover topology of a network without having direct access to the devices then you are looking at neighbor discovery which can work at lower levels. For devices out of range to give you information there are proprietary methods and protocols and could be device specific. e.g. Cisco IP SLA.

Instead of reinventing the wheel (unless that is exactly what you want to do) I would go with Phil's recommendation of OpenNMS. There are also others like NMap

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thanks, i don't want to reinvent the wheel haha, it's just that i haven't found any tool that do that, i will give it a try a those, and the snmp approach was the one i had in mind, let's see what i can do, thank you very much – Paulo Bu Feb 16 '11 at 6:54
+1 on Vangels' comment - unless you are doing this as a training exercise, there are lots and lots and lots of available products that do this for you. – Phil Hollenback Feb 16 '11 at 6:54
Thanks Phil. Ike, additionally Solarwinds has a whole complement of such tools, some free , some trial. you might want to take a look at their stash. I think their Orion NPM will do the best job, it works quite well on WAN as well and supports many devices. No free tools will come close to commercial tools in the ease of setting up and getting done what you want to do. I applied for a job there twice and got rejected twice ^^ – Vangel Feb 17 '11 at 8:09
any tools would be fine for me, but i need to know how they work at least becouse the network where i'm gonna test it it's pretty messy and serviceless (snmp) hehe, would be there any way to accomplish this without snmp?? i dont thinks so – Paulo Bu Feb 17 '11 at 15:10

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