DNS/DHCP

[Fred Martin_1]

I've been using static IP addresses all along, and have always been a flat network; we're about to subnet and that presents the problem of how to move laptops from subnet to subnet.

Prior to subnetting I could connect a laptop to the flat network in any location and keep my own static IP address.

I'm not ready to go to DHCP for -all- my hosts. I was thinking that perhaps I could have a pool of DHCP addresses at each subnet, and when a latop appeared there it would be given a local address. And a local name?

I'm not quite sure this is a reasonable method of setting this up, nor what it will do to my DNS setup - i.e. do I just leave the pool addresses out of DNS?

I'm open to any general discussion about this and will probably have more specific questions.

[Geoff Wild]

Depends - do you need reverse DNS for your laptop users? if so, then yes - setup DHCP.

Rgds...Geoff

[Fred Martin_1]

I suppose it could be similar to what I now do for VPN ... I have a pool of addresses in my DNS, with names VPN01, VPN02, etc. and the VPN server assigns addresses out to he clients as they log in, from the same pool.

Are there issues created since the DNS name doesn't match the computer's name as configured in the Net Properties on the laptop?

[Geoff Wild · Accepted solution]

THe DNS name doesn't have to be the same as the computer name - that is looked after by WINS - so, if you have a WINS server - then from a Windows machine - pinging the laptop name will be the same as pinging the DHCP name.

Rgds...Geoff

[Fred Martin_1]

We're not running WINS now. Currently the laptops, since they have a static IP address anyway, are set up in DNS.

We set the hostname in the DNS A-record to be the same as the NetBios name of the laptop (Net Hood Properties sheet), as a matter of policy.

When I look into 'Net Hood' in Windows, I see the connected laptop, and it shows the Netbios name, as declared by the laptop itself.

So as I described it, by running DHCP, and giving DNS pre-assigned generic names for a pool of addresses that match the DHCP pool of addresses, basically you could see 'Laptop6' in Net Hood, but not be able to ping it by that Netbios name as we can today, since DHCP would have assigned an unknown address from the pool, and DNS would have given it a generic name based on that address. Right?

I realize that this is literally just semantics and I can live with it, I just wanted to be sure that's the expected result.

[A. Clay Stephenson]

Let me tell you what I do --- and I wouldn't be caught dead using a WINS Server.

Download BIND and DHCP from the guys who invented the stuff --- www.isc.org. The source is very easy to compile and link and now you have an extremely powerful version of both named and dhcpd. You have the option of always handing out the same IP address to the same MAC address or it can even hand out a static IP address to a MAC based upon what subnet the request comes from. This means that a laptop ueser who travels within your company might two different static IP addresses. Best of all, you can set the system name to "cstephen" on the laptop and when dhcpd hands out an IP address (either static or DHCP'ed), named is notified and you can actually do a hostname lookup on cstephen.xxx.yyy.com -- that's dynamic DNS and it's quite nice.