SwOS - DHCP Client

Any chance of adding DHCP client support for management address?

I currently use a DHCP server w/ RADIUS auth and static reservations to assign management IP’s to AP’s and RB750UP switches.. It makes renumbering / subnetting networks easier. Looking at moving to 260GSP’s platform to replace RB750UP, but it’s lacking a DHCP client interface for management address.

I know these devices need an IP to access the management (web) interface, so it would also need to be able to have a fallback IP if DHCP server was unresponsive/unavailable for some reason (192.168.88.1).

Seconded! With all the development made to SwOS lately, I’m surprised it still has only static IP capability. Just to be able to pick any switch out of a pile, put it on a network without any special handling, and be able to access its admin interface would be a real time-saver.

I don’t know much about your specific environment, but dynamic addressing of infrastructure is generally considered a VERY bad idea. Unless you’re using dynamic DNS updates to an internal DNS server to track which IP’s have been registered to unique infrastructure device hostnames, you have no way to reliably and consistencly reach those devices. Also, many 3rd party products used to infrastructure device management rely on being able to reach devices at the same IP consistently. What’s so hard about plugging your laptop in and setting the MIP before deploying onto a production network? Gives you a chance to ensure you’re on the latest firmware as well, since disrupting the production network with infrastructure upgrades is also generally frowned upon (a necessary evil, but one that should be VERY carefully managed).

With static DHCP leases, all the addresses are stored on the DHCP server. Addresses, default gateways, routing etc. for an entire broadcast domain can be managed from one device.

Agreed, but if you’re using static DHCP leases, the switch will always end up with the same IP. What if you need to deploy a switch to a different network segment on which the statically assigned DHCP lease is invalid? Now you have an unreachable switch that may or may not be configured to handle the correct VLANs for that network segment.

Unless you have a VERY large subnet allocated for management IPs, AND you setup a standard configuration on EVERY switch (i.e. port 1 is always trunk port, trunk port set to carry management VLAN, etc.), what you’re talking about is impractical. Not only that, but you’re going to have to manually configure every one of those switches to set up your standard config, so where are you really saving time? On top of that, SwOS doesn’t do routing, or even take a default gateway when you configure it. For that matter, you don’t even configure a subnet mask on it! So all you’re really doing is statically mapping an IP address to a device, since no other parameters are configurable via DHCP.

Each device would always end up with the same IP… until I change any or all of them at the same time from one place.

What if you need to deploy a switch to a different network segment on which the statically assigned DHCP lease is invalid? Now you have an unreachable switch that may or may not be configured to handle the correct VLANs for that network segment.

If you move the device to a different subnet, you’re talking to a different DHCP server. Worst-case scenario: the switch would get a dynamic DHCP lease from the new server (which you could then make static and assign the desired address), and the switch’s web interface would be reachable immediately. Better still, you can copy the static DHCP definition from the old server to the new and adjust the IP, and the device would get the desired address upon initial power-up. This is how it works with any DHCP-capable device that I use (i.e., all of them except SwOS).

Unless you have a VERY large subnet allocated for management IPs, AND you setup a standard configuration on EVERY switch (i.e. port 1 is always trunk port, trunk port set to carry management VLAN, etc.), what you’re talking about is impractical.

Impractical? I do this now. SwOS is the only network device to which I have to assign an address manually before taking it into the field–in fact, at the moment it’s the only device of any type. Routers, switches, APs, IP cameras… everything else, I can grab a handful off the shelf and hit the road, and it doesn’t matter which one I connect where: it becomes reachable on the network, and I can configure it from there.

I’m not saying I don’t still have to configure switches differently for different locations; this is only about accessibility of the web interface. Just making the device reachable at its destination without special handling would save time. If SwOS had something analogous to MAC Winbox, it wouldn’t be so bad: you could still log on and configure it, even if its IP doesn’t match the network. But as it stands, if you don’t already know its subnet, the only ways to get onto a SwOS device are 1) a very lucky guess or 2) clearing its configuration and starting over. And when deploying more than one device (e.g., replacing a dozen RB750UPs with RB260GUPs), they aren’t interchangeable: you have to keep track of which one has the right address for which network.

Not only that, but you’re going to have to manually configure every one of those switches to set up your standard config, so where are you really saving time?

In this case, the only “standard config” I need would be to enable DHCP–which, I would argue, should be the factory default for networking equipment anyway. Like I said, this is mainly about making the SwOS web interface accessible on even a simple network without special handling.

I guess the point I’m trying to make is that if the switches are always plugged into the same network segment (i.e. same VLAN), then why do you need DHCP on them at all? Since you have to manually do some sort of configuration to begin with (trunk config, management VLAN, hostname, etc.), why not just set its static IP at that time and be done with it? I just think that what you want is a solution to a perceived problem that doesn’t actually exist. Just my opinion, based on my own style of network management.

If lack of DHCP were a nonexistent problem, everyone else wouldn’t have included it. SwOS is the only network device I have that doesn’t have a DHCP client. Even Ubiquiti IP cameras have it. Evidently, many people recognize its usefulness.