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IPAM Multiple IP Addresses to One MAC Address

Is there a way to document in IPAM devices that have multiple IP addresses tied to a single MAC address and by extension in Win DHCP? We have this situation in our manufacturing area where a PLC has a single MAC address and multiple IP addresses behind it. Thanks!

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KMSigma.SWI

IPAM should 'see' this if you are scanning those subnets. As far as the Windows DHCP, it may also show up there, but I rather doubt it since DHCP is designed for single MAC --> single IP.

(Also, moving the IPAM forum for better visibility)

qerickson1

Thanks for the quick feedback. We aren't scanning the subnets with IPAM but rather manually uploading spreadsheet data in an effort to eliminate the spreadsheets and manage with IPAM going forward. Also, we'd like IPAM to update WIN DHCP servers with reservations etc. and don't know if this multiple IP to one MAC issue will fly with MS DHCP.

KMSigma.SWI

Totally understand - IPAM is an excellent 'replacement' for spreadsheets. (I got it for the exact same thing when I was a customer).

As far at the MS DHCP thing, I don't think any DHCP Server (Windows, Linux, Infoblox, etc.) can handle a single MAC with multiple addresses. I may be wrong in this, but I've never seen it working in the way you describe.

I know (from experience) if you want multiple IPs on the same physical interface that's fine (I used to do this web servers all the time), but they always had to be defined statically. It wasn't that much of a big deal and the operating system took it in stride because it was designed that way. But DHCP was never going to work on them.

This is actually one of the places that IPAM can shine because it scans and looks up the MAC address of the remote device. Then it's just a matter of making sure that you keep track in a way that makes sense for your organization. For my company, I used to have a report (long lost) that showed a MAC address and the IPs associated, but it was filtered for only devices that had more than 1 IP per MAC. Was very useful when we needed to audit our web farms and things like that.

qerickson1

In a previous life we had to handle this with pseudo MAC's in Infoblox. We had to change one char of the MAC to add the multiple IP's but that was long ago. Is this something we'd need to do in IPAM or can we just manually add multiple IP's with same MAC without it complaining? I was pretty sure the feed to the MS DHCP server was going to be an issue with this.