IP/MAC binding or ARP... Is this my issue? and some one explain the practical difference..which to use ? or both?

[Neil P]

Have read many pages about layer 2, layer 3 ..and all sorts of other stuff..but nothing explaining the simple and practical differences. and which to use.to bind my device to an IP address

My issue is to do with binding a home control device (TIP10RF interface) to a specific MAC address.
It is connected to the DHCP router via a pair of Prosafe switches daisy chained to the DHCP router a Netgear Model No. TD-W8980 N600.


I can set the MAC address in the MAC IP binding table ..but it never 'sticks.

After a reboot, (of either router or interface)m it always comes back with another IP address.

This is a pain because I use Port Forwardigin tot he device to allow access to it from outside the home


Have seen the ARP table. that also seems to do "MAC/IP binding" but in a different way.

I have read a lot about the differences..but nothign that haas actually helps me to know if I should set the device MAC / IP address combo in one or the other or both.

The device itself does not have a config page to administer it.

Any ideas please ?

 

[nigelivey]

You should just be able to reserve the IP within the router (to the MAC) to an IP address outside of the DHCP scope but within the same subnet. The switches are not a factor, if they are unmanaged they know nothing of Layer3 and IP, and are purely L2 devices. It is unclear if they are managed or not??

 

[Neil P]

The switches do have a Management interface, yes, but I’ve not seen anything that looks like it should have effect on DHCP.

As you say, reserving an IP based on MAC at the router should do it, but since adding the switches it does not.

Maybe you have solved my issue though. Previously my reserved address was WITHIN the DHCP scope. I had always had reserved addresses within the DHCP scope in the past, and it always worked...maybe just lucky ?

 

[kanewolf]

Yes you should definitely have space from your class C address range reserved for non-DHCP addresses. It will depend on the number of dynamic clients you need to serve, but 10-50 addresses (I like .200 to .254) is a good range of static IP addresses.
Having a reserved address in the DHCP range is just asking for an IP duplication. Those are bad.

 

[Neil P]

going to be difficult now, as I have a selection of different 'sites' on the network..
I have set home one in the '50-100 range, bridge to farm as 100 to 150, CCTV as 200-250...

so all the 'blocks of 50 ' taken up with a different 'site'...there are no /.... looks like a major rethink of all the point is going to have to be done to make it work again 🙁

 

[kanewolf]

How many DHCP devices do you have to support?

 

[kanewolf]

For my home network (about 40 devices) I keep a spreadsheet of devices grouped by functionality. I have another tab that automatically maps all the rows in the functionality tab to a numeric order. I keep MAC addresses, IP addresses, whether MAC assigned static, device static, or DHCP. I also list all the network services each device uses like NTP, SNMP, Syslog.

 

[Neil P]

How many DHCP devices do you have to support?

Actually very few probably, visitors to the site / home/ farm/ stables etc and none are business critical , so actually not really an issue I suppose

Could move a few of the fixed IP devices up, move a few down, and give my self a block of 30-40 in the middle somewhere .

The fixed devices are IP cams or media servers, or the AP's , or switches/ etc. 32 fixed IP address devices ...

 

[Neil P]

Like the spreadsheet idea...as I add devices as the home audio and home control stuff gets added.....it is going to get more complex...guess I should start some better organisation now.

Thanks for the tip

 

[kanewolf]

My DHCP range is set to .151 to .199 I have static groups, based on functionality setup around that range. Network devices, switches, printers, UPS interfaces are setup above 200. Cameras are .80 to .99. Cell phones and tablets are .14x, etc. There is nothing special about an IP address. If you have everything well documented you can use any available address outside your DHCP range.

Since this is a business, I might recommend a couple changes.
Get a business class router that can have independent DHCP servers and VLANs. You setup a VLAN and independent IP address range for the guests. That way they have ZERO access to the business network but can still have internet access.
Use business class WIFI equipment. Setup multiple SSIDs that can be VLAN tagged and have independent passwords and/or no-passwork guest WIFI
Configure your switches to support VLANs to provide the isolation I described above.
If this is too advanced, bring in an expert to help out.

 

[Neil P]

It is not so critical as to be a full on business with business computers etc...as such, so not going to go to the extent of VLAN's etc.

I had set it so each "site" had its own block, so the stable area was furthest away from me, so in the 200-250 range, home use where the net connection is 0-50, BBQ/ party area next at 50-100, workshop 100-150 and rented sheds 150-200.
IP ranges set greater for greater physical distance from home... merely for ease of remembering, what each block was and if adding a new device.

Could easily bring the 100-200 devices into the 100-150 range..leaving the 150-200 for the DHCP range.
Thanks for the help
NP