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So I thought I knew how to set up my DHCP Server on my 3550 switch and reserve IP's for clients.

I go into the pool I need to reserve the IP in, but I do not have the address command as an option to do it like I have in the past on IOS.

xxx3550#sh version 
Cisco IOS Software, C3550 Software (C3550-IPSERVICES-M), Version 12.2(35)SE5, RELEASE SOFTWARE (fc1)
Copyright (c) 1986-2007 by Cisco Systems, Inc.
Compiled Thu 19-Jul-07 21:08 by nachen
Image text-base: 0x00003000, data-base: 0x00D45C28
ROM: Bootstrap program is C3550 boot loader
xxx3550 uptime is 1 year, 30 weeks, 6 days, 2 hours, 3 minutes
System returned to ROM by power-on
System restarted at 07:35:09 EDT Thu Oct 22 2015
System image file is "flash:c3550-ipservices-mz.122-35.SE5/c3550-ipservices-mz.122-35.SE5.bin"
Cisco WS-C3550-24-PWR (PowerPC) processor (revision L0) with 65526K/8192K bytes of memory.
Processor board ID CAT0937R3D4
Last reset from warm-reset
Running Layer2/3 Switching Image

Here is the DHCP pool config

ip dhcp pool data
   network 192.168.5.0 255.255.255.0
   default-router 192.168.5.1 
   dns-server xxx.xxx.xxx.x xxx.xxx.xxx.x 
   lease 8

When i go into dhcp pool configuration I do have the following available:

xxx3550(config)#ip dhcp pool data 
xxx3550(dhcp-config)#?
DHCP pool configuration commands:
  bootfile             Boot file name
  client-identifier    Client identifier
  client-name          Client name
  default-router       Default routers
  dns-server           DNS servers
  domain-name          Domain name
  exit                 Exit from DHCP pool configuration mode
  hardware-address     Client hardware address
  host                 Client IP address and mask
  import               Programatically importing DHCP option parameters
  lease                Address lease time
  netbios-name-server  NetBIOS (WINS) name servers
  netbios-node-type    NetBIOS node type
  network              Network number and mask
  next-server          Next server in boot process
  no                   Negate a command or set its defaults
  option               Raw DHCP options
xxx3550(dhcp-config)#

I just need to reserve an IP address for a specific MAC Address. I usually do Address xxx.xxx.xxx.xx Hardware-Address AABB.CC00.11FF

  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide your own answer and accept it. – Ron Maupin Aug 7 '17 at 0:01
1

There is a solution to avoid the multiple manual bindings.

Here is a link to Cisco documentation concerning DHCP origin and database files:

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_dhcp/configuration/15-mt/dhcp-15-mt-book/config-dhcp-server.html

Essentially, you need a tftp/ftp server that records leases from the DHCP server in a database file (text file) on the Cisco device and reads the origin file (also a text file) in which you create all the manual bindings you need.

I use this as a disaster recovery tool in case of an unplanned reboot of the Cisco DHCP server:

  • The binding database saves the network from a DHCP storm and consequent Denial of Service against the DHCP server (self-imposed in the case of not having the binding database).
  • The origin file allows my static bindings to exist and can be edited programmatically as it is only a text file.

The above link contains examples and further reading links. For older IOS versions (back to at least 12.4) you can refer to similar online resources.

| improve this answer | |
  • I guess this would be my solution, fortunately I have upgraded that switch now and have the commands available to get this done. – veel84 Aug 7 '17 at 15:14
3

You have to create another pool with client-identifier and your Client ID, which usually defaults to MAC prepended with 01 (Ethernet client), or hardware-address and your MAC like this:

ip dhcp pool my-host
    host 10.0.0.1 255.255.255.0
    client-identifier 01AA.BBCC.0011.FF

If you prefer to configure it manually, please have a look at:

ip dhcp excluded-address <first IP> <last IP>
| improve this answer | |
  • Do I have to do a pool for each static IP i want to reserve on the server? – veel84 May 25 '17 at 14:27
  • @veel84 unfortunately, there are no other options available, unless you try an external DHCP server :( – Andriy Berestovskyy May 25 '17 at 14:44

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