Using DHCP reserved client options for certain devices

This content is 14 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

I’ve been struggling with poor Internet connectivity for a while now – the speed is fine (any speed tests I conduct indicate a perfectly healthy 3-5Mbps on on “up to 8Mbps” ADSL line) but I frequently suffer from timeout, only to find that a refresh a few moments later brings the page back quickly.

Suspecting a DNS issue (my core infrastructure server only has a Atom processor and is a little light on memory), I decided to bypass my local DNS server for those devices that don’t really need it because all the services they access are on the Internet (e.g. my iPad).

I wasn’t sure how to do this – all of my devices pick up their TCP/IP settings (and more) via DHCP – but then I realised that the Windows Server 2008 R2 DHCP service (and possibly earlier versions too) allows me to configure reserved client options.

I worked out which IP address my iPad was using, then converted the lease to a reservation. Once I had a reservation set for the device, I could configure the reserved client options (i.e. updating the DNS server addresses to only use my ISP servers, OpenDNS, or Google’s DNS servers).

Unfortunately I’m still experiencing the timeouts and it may just be that my elderly Solwise ADSL modem/router needs replacing… oh well, I guess it’s time to go back to the drawing board!

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