Sonic3 Posted September 26, 2019 Posted September 26, 2019 I have to find out the IP addresses of all the switches on the network, for which there has been no previous record, and have come up short. I still have 11 switches that I've physically identified but cannot for the life of me find out their IP addresses. I've tried multiple IP scanners including Advanced IP Scanner and LanSweeper, manufacturers' own tools such as Netgear Switch Discovery and Cisco FindIT, and plugging a laptop directly into them and taking out the uplink before scanning. I've pretty much attempted to load every IP address into a web browser on the off chance it's a switch management page! I'm really stuck as for what to do next, other than reset them to factory defaults. Is there a trick I'm missing? The switches are: [TABLE=width: 500] Make Model Avaya Level One Level One Cisco Cisco Catalyst D-Link Netgear Planet Level One Netgear Networx 3510GT-PWR+ GES 2450 GES 2450 SLM2048 3750 v2 DES-1024R+ GS724T GSW-1600HP GES 2450 GS724T "24 port web smart switch"
bald_pig Posted September 26, 2019 Posted September 26, 2019 They are probably still on a default address and not picked up DHCP. Check the default ip address for each switch, set your laptop to be on the same range, then connect directly to the switch and connect to the default ip in your browser. 1
Jcx500 Posted September 26, 2019 Posted September 26, 2019 Have you logged in via serial and set an ip via that way
dgsmith Posted September 26, 2019 Posted September 26, 2019 Some switch makers bundle or allow you to download discovery software to find any of their branded devices, even if it's on a different subnet (then change the IP from the utility). I have done this many times before, though I do find often that dhcp allocates an IP. You may be able to check the mac address of dhcp allocations against the MAC of the switch(es) which is typically affixed to a sticker on the switch.
fiza Posted September 26, 2019 Posted September 26, 2019 If the switches are on the network can you not use the CLI to look at neighbours if you have identified the IP of some?
p858snake Posted September 27, 2019 Posted September 27, 2019 I've pretty much attempted to load every IP address into a web browser on the off chance it's a switch management page Are you sure they are setup in managed mode, and will have a ip address? they could be running in dumb mode as well because they haven't been configured.
PotNoodleTech Posted September 27, 2019 Posted September 27, 2019 If you have a decent network tester, or can borrow one or call a favor from a contractor, there's usually a mode for plugging cat5 straight into a switch, and it'll tell you the IP address etc of the switch it's connected to. My ideal network tester does this and I am sure the fluke ones your contractors may have will. Also - if they have not been given static Ip addresses you may be able to find them in your DHCP scope as often they show up as blank name (just an ip address) unlike all your windows PCs which will be identifiable. 1
Sonic3 Posted September 27, 2019 Author Posted September 27, 2019 They are probably still on a default address and not picked up DHCP. Check the default ip address for each switch, set your laptop to be on the same range, then connect directly to the switch and connect to the default ip in your browser. YES! Thank you, that was it! I don't quite understand how though. I mean all the switches are working fine which must mean they are on our network's subnet/range which is 10.220.84.0-10.220.87.254, but their login IP addresses are e.g. 192.168.1.1 ??
mrstrong Posted September 27, 2019 Posted September 27, 2019 switch doesn't have to have an ip to work, e.g. like the cheap unmanaged ones you can buy. most switches will forward Ethernet frames without any configuration. This means that you can buy a switch, plug in the right cables to connect various devices to the switch, power it on, and the switch will work properly. However, to perform switch management over the network the switch will need to have an IP address.
bald_pig Posted September 27, 2019 Posted September 27, 2019 YES! Thank you, that was it! I don't quite understand how though. I mean all the switches are working fine which must mean they are on our network's subnet/range which is 10.220.84.0-10.220.87.254, but their login IP addresses are e.g. 192.168.1.1 ?? Switches don't actually need to be on the network, they just build a database of which port they can contact an ip address through, and sling any packets it receives through the appropriate port. (Heavily simplified) 1
Sonic3 Posted September 30, 2019 Author Posted September 30, 2019 All switches have been accounted for. Thanks everyone
TomHD Posted October 1, 2019 Posted October 1, 2019 Just wanted to add some references to the discover tools I use... Cisco - FindIT 2 Netgear - Smartwizard Discovery DLink - Smart Console Utility Also Hewlet Packard make a tool called "HPE Network Discover Tool" which I've found very useful for discovering whats on a network, it will only discover hardware that is on the same IP range and subnet so not really useful for finding non-configured switches 1
TomHD Posted October 1, 2019 Posted October 1, 2019 Just looked at that LDWin and its a great little tool, well worth having on your service laptop
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