I'm actually not very knowledgeable about switches, but I've tried to find a solution to my problem in the various manuals and have been unsucessful.
I am administering a Catalyst 2960S switch and I would like to connect several computers to it. Some of those each have a static IP address. For a few of them, I would like the switch to dynamically assign an IP address to them via DHCP. Is the switch capable of doing this? If so, how can I do it?
I tried looking through Cisco Network Assistant and I couldn't find it. Some web pages have suggested I telnet into the switch and issue commands like "ip dhcp ?" to see what commands are possible. I can telnet in and if I type but I get an "Unrecognized command" for both "ip ?" and "ip dhcp ?". This makes me think I'm reading the wrong web pages.
I'm completely lost. Any pointers would be appreciated! I did come across the term "DHCP snooping". It seems relevant, but very difficult for me to grasp. Is that what I should be reading?
Solved! Go to Solution.
Thank you for the prompt reply!
I've seen replies such as that before during my Google search. However, I'm not sure how to get to the part where I can enter commands such as "id dhcp ...".
When I telnet into the switch, commands such as that do not work (as I mentioned in my original post). Do I need to do something before issuing the commands mentioned in the link you posted?
That doesn't work for me...I still must be doing something wrong. This is what I get:
Connected to XXX.XXX.XXX.XXX.
Escape character is '^]'.
User Access Verification
% Invalid input detected at '^' marker.
Switch>ip dhcp pool
% Invalid input detected at '^' marker.
<1-99> Session number to resume
access-enable Create a temporary Access-List entry
clear Reset functions
connect Open a terminal connection
crypto Encryption related commands.
disable Turn off privileged commands
disconnect Disconnect an existing network connection
enable Turn on privileged commands
exit Exit from the EXEC
help Description of the interactive help system
lock Lock the terminal
login Log in as a particular user
logout Exit from the EXEC
name-connection Name an existing network connection
ping Send echo messages
rcommand Run command on remote switch
release Release a resource
renew Renew a resource
resume Resume an active network connection
set Set system parameter (not config)
show Show running system information
Am I in the right menu? Is the ability to change configurations via telnet turned off and I have to turn it on somehow? I'm telneting in remotely to its IP address. Should I be connecting a cable directly to it and trying that instead?
Thank you for your help!
Ah! That worked! Thank you for literally hand-holding me... I kept thinking I need to telnet in differently (i.e., via a cable while sitting next to it).
I'm going to configure the DHCP later when I am physically next to the switch so that I can reset it if I make a mistake. I will let you know if I am stuck.
But I have one quick question. In the menus, I can use "?" to find out what a command does. i.e, "configure ?" Is there a PDF document on Cisco's web site that explains each command. For example, the discussion you first showed me said I should type these commands:
ip dhcp pool test
network 192.168.50.0 255.255.255.0
Is there somewhere that explains to me what the above means. (I *guess* it means to set up a DHCP pool for 192.168.50.0/24 with the cisco.com domain, etc.) But is there something I can look at that explains the commands better? Or a term to Google for that is the name for this configuration method/"program"?
Thank you for your help (and prompt replies!)! I've been stuck on this for days...
Glad to help
The best place for this type info is the configuration guide. It will go step-by-step and explain each command.
Also, as you have already found out, ? in Cisco IOS is your friend. If you are not sure just type ? and the IOS will give all the keyword that could added next for example after you type config t type ip dhsp and than a ? you will see the rest of the options
here is an example
Switch# config t
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)#ip dhcp ?
aaa Configure aaa attributes
binding DHCP address bindings
bootp BOOTP specific configuration
class Configure DHCP classes
conflict DHCP address conflict parameters
database Configure DHCP database agents
excluded-address Prevent DHCP from assigning certain addresses
limit Limit DHCP Lease
limited-broadcast-address Use all 1's broadcast address
ping Specify ping parameters used by DHCP
pool Configure DHCP address pools
relay DHCP relay agent parameters
route Specify the type of routes for clients on
smart-relay Enable Smart Relay feature
snooping DHCP Snooping
subscriber-id Global subscriber-id configuration
use Configure use of certain parameters during
Also, for what you are trying to do you don't need to be sitting close to the router or switch you can easily configure it using telnet. You also don't need to reboot the switch after configuring the DHCP pool. Just follow the example in the link I provided and you should be fine.
Thank you for your help and sorry for not getting back to you. I was pre-occupied with something else the last few days.
However, I got back to it and was unsuccessful. I noticed the original link that you sent to me was from a 2006 posting. Could the instructions be out-of-date?
These are the commands I issued:
(config)# service dhcp
(dhcp-config)# ip dhcp pool test
(dhcp-config)# network ...
(dhcp-config)# lease ...
(dhcp-config)# address 192.168.50.1 hardware-address ...
Doing "show ip dhcp binding" tells me that the pool seems to have been set up correctly. (The "type" is set to "Manual"; I'm not sure if that's the problem.)
Neither "ip dhcp snooping" nor "interface vlan 1" seem to work, so I've done nothing with that. And I don't know what the "default router" should be.
On this switch, a few ports are static addresses; on another set, I would like DHCP to assign addresses to them. I made them into separate VLANs. But I tried them all on one VLAN or on two separate VLANs and neither worked.
I also found the "IOS IP Addressing Services Command Reference" which explains the commands, but doesn't tell me what I could be missing. I feel like I'm one command away from getting it working; I just can't tell which command is it. :-)
Thank you for your help!
Also, navigate the command reference guide for the 2960 series switches. It has all the commands you need with definitions