Getting lost trying to sort DHCP settings

Simon84uk

Simon84uk

Simon84uk

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Joined
25 May 2011
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20
Location
Southampton, UK
Hi All,

I have three devices currently in my network fighting to control DHCP, everything I've tried so far (with limited knowledge admittedly) results in a very unstable internet and general network connection.

Could someone please advise how to go about setting up my devices so the IP's are handled correctly and the two WAP's work together. Currently I have the DIR-880L off as it just kills everything when it's on, I have it set to it's own SSID for now also in case that was causing any issues. But seems to be irrelevant.

Here are the three devices which can control DHCP.
  • D-Link DIR-880L (WAP, main switch on port 1, nothing on WAN port)
  • BT HH5 (Modem & WAP, main switch on port 1, 8-port media switch on port 2)
  • Netgear JGS516PE (Main switch, HH5 & DIR-880L connect to this on non PoE ports, 5-port switch also connected here for my office, and my IP PoE camera)

I would prefer the DIR-880L to control the DHCP assignments ideally as this has the most "friendly" UI.

I have tried putting all the devices on the same 192.168.1.* range and same 255.255.255.0 subnet, have also tried having DHCP controlled by each device individually with them set as the DHCP server. I can't seem to get it right, could one of you guru's give me any advice or pointers?


Many thanks,
Simon
 
The problem you are going to have is anything serving DHCP requests is going to set itself as the default gateway

To keep it simple I'd turn off the DHCP server on the DIR-880L and use the DHCP server on the HH5

What kind of connection have you got ? I'm presuming ADSL? (If you've got BT Infinity, you could get hold of a HG612 modem & use the DIR-880 as the router and ditch the HH5 completely)
 
Log in to the HH and turn off the DHCP server.
Make sure the HH is set with a static IP and in the correct subnet. Lets say 192.168.1.1 on a subnet of 255.255.255.0

Then switch on the D-Link and log into that.
Make sure this has a static IP too for ease of admin. Lets say 192.168.1.2 on the same subnet of 255.255.255.0
Also, check the DHCP pool configuration on this device as it needs to know what range it can use to give out IP's to devices configured to get their IP from here. Lets say a DHCP pool from 192.168.1.100 - 192.168.1.255 on the same subnet 255.255.255.0

Your first 99 IP addresses are therefore available for static assignment to devices eg 192.168.1.1 through to 192.168.1.99 of which the above two devices use the 1st two of these.

Log in to your 8 port media switch and assign it an IP 192.168.1.3 on the same subnet 255.255.255.0

Log in to your Netgear switch and assign it an IP 192.168.1.4 on the same subnet 255.255.255.0

Check each device's admin interface other than the HH and check what they have for their Gateway entry and DNS entries. Set each to point to the HH's IP address is what I believe would be correct here.

Check each of your devices such as laptop's, PC's etc that they are configured to obtain an IP address automatically. Probably best to go around each one and renew it's auto IP address allocation eg open a command prompt on each PC and 'ipconfig /release' and 'ipconfig /renew'
 
Whichever device you choose to use as a DHCP server it'll need to specify the HH5's IP as the gateway. If you're going to use the D-Link you need to check if it's possible to do this; many routers assume that they're the gateway and can't be overridden.

For the limited number of times you need to mess with DHCP settings I'd leave the HH5 to get on with it. Disable DHCP on everything else and assign management IPs outside the HH5's DHCP range.
 
Thanks all for the great information.

I have BT Infinity 1 as can't get above the speeds of that on my line. I have a HG612 from my previous HH4 installation at the old house so this sounds like a good possibility if I can't get things working.

I started having a look over the weekend following guide from "thenewoc" and made some good progress before I had to take the mrs shopping, but seems to be the right steps.


Thanks all again,
Simon
 
I use BT HH5 as an Wi-FI access point/Ethernet switch( I am not sure if its the same as to what you're trying to do). I did research and I found a guide how to do this. You turn off DHCP on your secondary router, then change the IP address of that router so that it falls outside the range of your secondary router(192.168.0.1 to 192.168.0.253). So you allocate 192.168.0.254 for the secondary router.

It works great.

http://www.expertreviews.co.uk/networks/8046/how-to-use-the-bt-home-hub-5-with-another-isp
 
Yes, you want one and only one DHCP server. Whichever one you set as the server, you need to make sure the other two are set as wireless repeaters and DHCP forwarders so you can use the same SSID and IP range.
 
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