dns caching

[bwanaaa]

in looking at the habits of my kids, and most people, they have a set of websites they like to revisit. In fact this behavior is formalized in the existence of bookmarks. However, even though sites are bookmarked, it's not the ip addresses that are bookmarked but the web site names. This requires a dns lookup every time. I was wondering how much bandwidth could be saved if I had a dns cache that was dynamic. I know the hosts file is supposed to do this, but it is static. Is there a service i can run on Win7 that caches ip addresses behind the scenes so the browser can check it locally before going out to the net? I also know of a linux app called dnsmasq although i have never used it. DNSmasq can run in openWRT and DDWRT so dnscaching could be installed at the router level but I am still googling the basics. Before I spend hours doing this, can anyone tell me if this is an old solution that has been deprecated by something better/faster/newer?

 

[drebo]

DNS is very low bandwidth. There's no point in caching anymore.

 

[VirtualLarry]

Windows 7 already has a caching DNS resolver service running.

 

[bwanaaa]

ok. good point. how about latency then? would dns caching make the 'web surfing experience' smoother, faster, more responsive? and what would be the best way? per machine or on the router?

 

[VirtualLarry]

DNS is very low bandwidth. There's no point in caching anymore.

It's not the bandwidth, but the latency. If you had to go out and do a DNS lookup for every URL, then you have two round-trips, one for DNS, and one for the HTTP. If you can eliminate one or both of those by caching, you can save a lot of (perceived) time.

 

[dave_the_nerd]

I have a local DNS server, because I am lazy. (I can type in things like "ssh server" or print to "colorprinter" and as long as I'm in the house it works.)

It's a Linux VM running DNSMasq, which provides caching functions as well.

In terms of web responsiveness / latency: I can't really tell the difference, although I've seen people benchmark it and there is a pretty sizable theoretical difference. It just doesn't seem to amount to much in practical terms (a few tens of milliseconds per request.)

If your computer is sluggish, buy an SSD.

 

[Fardringle]

The only times that a local DNS server is really useful are if you have local names you want to host like Dave the Nerd said (or in a business environment), if your ISP DNS servers are bad (and then it's better to just use different public servers) or if the latency on your Internet connection is REALLY horrible (satellite, for instance). The first one is mostly just for convenience, the second can be fixed by using different public servers. The third one could actually make a noticeable difference if setting up the local DNS is something you're willing and able to do.

 

[bwanaaa]

thank you folks. makes sense that as network speed goes up, then low bandwidth events appear instantaneous. i guess this would have been a good thing when i was using a hayes 2400 baud modem.