ip address of my switch

ive been task to make out a list of ip addresses used at work. ive got everything except for the two switches that we have.

both are HP PROCURVE switches. exact model/series cant tell exactly (lost the sticky note that i wrote it to).

is there anyway i would know what the IP addresses are for both my switches?

thanks.

I'm a little rusty on networking, but unless they are managed switches, they won't have IP addresses.
Right?

whatsupgold trial will identify everything on your network

great utility

Otherwise find the router they are logged into and look for connected devices and figure out what hte IP is

The switch itself doesn't have an IP address. You can create VLANs and assign them IP address though. This is done on the management VLAN so you can telnet into the switch and program it without having to be consoled into it. The IP addresses on other VLANs are used for trunking protocols, involving the router I believe. This is with Cisco stuff, so since you're using HP switches, just tell your boss that switches are layer 2 devices and don't have IP addresses.

That isn't necessarily true, layer 2 switches can have IP addresses. I have some 2950s all of which have IP addresses. True to be technical it is a managmant VLAN which holds the IP, but it is still using an IP. It would seem to me that this is an audit of what IPs are used and for what, so just saying these devices don't have IPs is not a good way to go.

As already mentioned if they are not managed switches they won't even be capable of having IPs. Any application that can do a ping sweep of your subnet will report on what IPs are in use, and should let you know what is what. Another option would be Solar Winds, expensive to buy but they offer a free trial too.

Well according to the OSI model, layer 2 devices don't have IP addresses. The management features are a separate component of the switch. It is the virtual terminal interface components that have the IP address.

If you want some free software that will tell you every device on your network, google Look@LAN.

While everything you said is true Nocturnus, I have to agree with ErikD in that his boss wants a list of all IPs being used on the network. While the switch itself isn't using the IP (the VLAN is), the IP is still being used and his boss will want to know about that.

Only other option is to log into the switches and get the information there.

thanks guys.. a lot of informative thoughts in here.

i would think we have a managed switch as i did witness in our sys. adm. training on how the trainor was able to log in to one of our company's switch IP ADDRESS to troubleshoot our network.

our IT has assigned a range of 192.168.9x.20-49 for switches. ive done a ping on all 20-49 and cant find anything.

I use a program called Network View 3. It will tell you almost everything active and connected to your network.

Neur0mancer said:

whatsupgold trial will identify everything on your network

great utility

Otherwise find the router they are logged into and look for connected devices and figure out what hte IP is

Click to expand...

switches don't 'log' into anything. They aren't clients. sheesh

bapski said:

thanks guys.. a lot of informative thoughts in here.

i would think we have a managed switch as i did witness in our sys. adm. training on how the trainor was able to log in to one of our company's switch IP ADDRESS to troubleshoot our network.

our IT has assigned a range of 192.168.9x.20-49 for switches. ive done a ping on all 20-49 and cant find anything.

Click to expand...

Well you know what, It's time to find out what hp procurve whatever you have, get into the closet,.for crine out loud, your IT staff should no wtf they have on their network, managed or un-managed - sheesh - umm, it's their job

jajmon said:

Well you know what, It's time to find out what hp procurve whatever you have, get into the closet,.for crine out loud, your IT staff should no wtf they have on their network, managed or un-managed - sheesh - umm, it's their job

Click to expand...

So true. Network diagrams are good too.

i have netgear switches with IPs, there are a lot of web-managed switches out there now and they will def have ip addresses.

Just because a switch has a web/ssh/telnet interface with an IP address doesn't make it anymore then a layer 2 switch. Its just a little OS/Web Server in it for configuration purposes.

bapsky, if you have physical access to the switch, and it has a serial port, plug into it, find a server that doesn't get much traffic, check the arp table (arp -a in windows, arp in linux) before and after you ping the machine to find the address.

As far as I understood switches don't have IP addys until the router assigns it. This is done as soon as something is plugged into it. Common misconception is that switches are smart. It's the router (software) that makes the ports on a switch intelligent. Of course each port does have a MAC address. But if a switch is intelligent, it's because there is management software in the frimware of the switch. In a case where there is no router, machines can still recieve IP's because most operating systems have router (software) integrated. In Windows this would be considered ICS. Iow, a 5-port router is nothing more than a 5-port switch with router (software) built in, making one of the ports an uplink. Picture a switch as a "crossover." Without it, you would need a crossover ethernet cable in order to network two machines, using the built in router (software) of each, or one machines ICS (acting as DHCP). In this scenario, the crossover cable does not have it's own IP addy persay, and neither does each NIC's port, until it recieves one from DHCP (plugging it in).

OK, this is getting kind of out of hand. Switches are OSI layer 2 devices, they only know about physical addressing, MAC addresses. Switches can't have an IP address themselves, but can uise up an IP address. More complex managed switches have an IP assigned to a managment VLAN so you can access the switch accross the network for managment puropses. This doesn't make it anything other than a layer 2 switch, end of story. Doesn't matter how you access it, SSH, telnet, web, telepathically, it is still a switch.

Smokeys,

Much easier if you are going that route to just login to the console and look at the configuration, right?

Uqdroma,

A router would never assign an IP to a switch, see above comments. A switch would only have an IP if it got assigned for managment purposes by an administrator. Switches are smart bridges. They make forward filter decisions based on MAC address.

Routers, and dekstop OSs don't hand out IPs, DHCP servers issue IP addresses and keep track of leases. It is possible to configure most routers as DHCP servers. ICS will kind of act as a lame DHCP server.

A router is not just a switch with an uplink port and special software. A router segments broadcast domains, a switch collision domains. A router can have an integrated switch, but they are different things. The router will handle all decisions based on interconnecting networks, and the switch will handle all internetwork traffic. A switch is much more than a simple crossover, so it isn't really true to say that a crossover cable can take the place of a switch.

Thanks ErikD, I've never had it clearly explained like that before, but it truly makes sense to me now.

thanks for the input guys.

i am able to identify connected devices by running an ARP TEST through the router.

i am able to account for all the ip addressess. all belonging to a certain device but not the switch.

what gives?

Well unless some traffic has been destined for the switch recently it will have timed out of th arp cache. You best bet i a network scanner that will do a ping sweep of the subnet or connecting directly to the switch and logging into the consule.

Also, it might not be using an IP (kind of doubtful in this situation though).

ErikD said:

A router would never assign an IP to a switch, see above comments. A switch would only have an IP if it got assigned for managment purposes by an administrator. Switches are smart bridges. They make forward filter decisions based on MAC address.

Click to expand...

And there you go, FTW.

Switches don't give a flying fig for IP addrs; if it's a managable switch, you can configure an IP on the management interface and maybe get SNMP traps, stats, or configure a port for auto/100full/10half, etc. If it's not managable, like the Netgear or Linksys switch you have at home, there's no management interface to configure an IP and it's plug and play. Either way, a managable switch works the same as an unmanaged switch, which is to forward frames by MAC addr.