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I think I know the answer to this, but thought I ought to ask around.

When setting up new networks with multiple hosts, like a university computer lab VLAN with 30+ workstations, for instance, is it possible to configure the new end devices, via Cisco (or any brand, really) network devices?

The reason I ask is I've been playing and practising network design and implementation with some older Cisco hardware. Particularly several refurbished Catalyst 2960 layer 2 switches and Catalyst 3560 multilayer (i.e. layer 2 + 3) switch. At first, it seemed to take me forever to do anything substantial with Cisco's IOS operating system, but I've gradually picked up on ways to get things done quicker; apply commands to ranges (of interfaces, etc.), control and push configurations to multiple switches via the multilayer switch, and so on.

For example, instead of doing something like:

enable
configure terminal
interface FastEthernet0/1
switchport mode access

Twenty-four times, or once per interface, you could just do:

enable
configure terminal
interface range FastEthernet0/1-24
switchport mode access

Once. You could even save time typing and just do:

en
conf t
in range f01/24
switchp m a

Or something to that effect.

But say, you set up DHCP pools from your layer 3 switch, configure trunking on the switches, and configure access mode for each interface that's connected to an end host, but none of the hosts have DHCP enabled by default. Do you then have to go through and enable DHCP on every single host, individually? Or can you somehow push that configuration through to a range of hosts simultaneously, so you only need to do it once, instead of 10,50,100+ (however many) times?

My first thought is, there's no way to do it, and that would probably be considered a massive security vulnerability in itself. But then again, I'm not sure. It could be time-consuming. And expensive. Well, there are other solutions, but still. It made me stop and think.

To illustrate, here's part of a network (there are twenty more just like this) that I'm designing with Packet Tracer, where each host is set to static by default:

enter image description here

Again, there are probably tricks that you can do, but my question persists.

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  • 2
    Since this question is really about host configuration it is off-topic here. For servers you might want to try on Server Fault. You can't configure your clients from a network device unless you've installed some kind of auto-configuration on the clients previously (client management agent, policy agent, ...). However, product recommendations are off-topic here as well.
    – Zac67
    Commented Oct 25, 2018 at 10:01
  • Many operating systems do have DHCP and/or PXE by default for exactly these reasons.
    – jonathanjo
    Commented Oct 25, 2018 at 11:49

2 Answers 2

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It depends entirely on the hosts and their operating system. Many hosts are actually DHCP enabled at factory settings, or will do PXE booting.

I've certainly run networks where

  • All the hosts were diskless, and were either Unix/Linux workstations or X11 servers, booting over PXE.
  • All the hosts were servers with disks, but which PXE booted if no operating system was available on their disk. The PXE boot installed the OS, with DHCP, and on reboot the systems were configured
  • All the hosts were Windows desktops, which were booted with a USB key, which PXE booted and then installed the OS.
  • All the units were IP phones, which booted with DHCP and then autoconfigured.
  • All the hosts were Arduinos with PXE boot code.

Hands-free deployment, in my opinion, is one of the most important reasons for having DHCP as default on user hosts, and PXE is just a souped-up version.

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You can’t configure your computers from a Cisco switch. You can however look into automation, e.g. Salt or Ansible to configure your end hosts quickly and easily.

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  • This really depends on the operating system. Certainly if the hosts run DHCP and can be telnet/ssh you can definitely configure them from a Cisco or any other device which can run telnet or ssh client.
    – jonathanjo
    Commented Oct 25, 2018 at 11:50

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