How to find all SUBNETS in company's network?
I want to know all the SUBNETS are available in the company network. Which tools should I use? (note: Yesterday, I was able to locate the ip address of some servers which are located at 60 Subnet by using ip-scanner as suggested from this forum).
Thanks,
tjie
Thanks,
tjie
Adam Brown
Depends on your network architecture. You can use a ping scanning utility to find all devices on the network in most cases (works better with port scanning capability), but that will not provide complete results on networks with fully segregated VLANs unless you run the scan from each VLAN or from a system that has access to all VLANs. Realistically, you can get a rundown of what Subnets are on your network by examining your environment's Router configurations. If you have only one router in the network, that device's configuration will show you all subnets on the network (unless those subnets do not have Internet connectivity). With multiple routers, you would need to examine and collate info from each Router.
Adam Brown gives you some good advice. I'd not suggest much better.
But, you could download Paessler's PRTG and install it on a workstation and let it automagically find network resources. It MAY find things that you can't see with other tools. It's easy enough to try. Then, if it's no help there's not much cost in having tried.
But, you could download Paessler's PRTG and install it on a workstation and let it automagically find network resources. It MAY find things that you can't see with other tools. It's easy enough to try. Then, if it's no help there's not much cost in having tried.
ASKER CERTIFIED SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Mostly you have to check configs of routers & switches.
Start with an entry point and document all networks known there
- Local attached networks
- Routes
- (+ Tunnels)
- Firewall filtr rules.
Then go through attached routers completing the picture.
After that do the same fro switches. This should complete the picture.
(routing will give you the network on L3) using the switch info supplements this with a wiring diagram + available networks. (L1 + L2).
Start with an entry point and document all networks known there
- Local attached networks
- Routes
- (+ Tunnels)
- Firewall filtr rules.
Then go through attached routers completing the picture.
After that do the same fro switches. This should complete the picture.
(routing will give you the network on L3) using the switch info supplements this with a wiring diagram + available networks. (L1 + L2).
I know that points are already distributed on this but I wanted to point out that if all you want is the networks that are in use, then most everything above is overkill or insufficient.
If it were me, I'd go to each router on the network and simply run a show ip route or equivalent. The only network that you won't find in this fashion is one that is 100% isolated and unrouted, in which case, the question becomes 1. Is it really on the network and 2. Why is it there to begin with?
If it were me, I'd go to each router on the network and simply run a show ip route or equivalent. The only network that you won't find in this fashion is one that is 100% isolated and unrouted, in which case, the question becomes 1. Is it really on the network and 2. Why is it there to begin with?