Free DNS service

I've seen plenty of services that offer free DNS service for domains. Does anyone know if there are any DNS servers freely available for web browsing purposes? E.g. I am a web developer and something that happens frequently is that I will be developing a new website at a temporary URL while an existing site is served from my client's domain name. When the new site is ready the domain name gets switched to the DNS servers for my hosting company, but by that time my ISP has cached the old DNS data, so I still can't bring up the new site with the domain name even though the DNS update has largely spread through the Internet. So what I would like to be able to do is temporarily set up my Internet connection to use DNS servers other than my ISPs. Possible?

I found a public proxy server and configured my Internet connection to use that, which had the desired effect. Then I can just turn it off after a day or two when my ISP refreshes their DNS data.

On Unix you could change your nameserver line in /etc/resolv.conf so it uses a local cache:

before:
[4:04:22] root@users /# cat /etc/resolv.conf
domain example.com
nameserver 1.2.3.4

after:
[4:04:22] root@users /# cat /etc/resolv.conf
#domain example.com
nameserver 127.0.0.1

although obviously this depends on your having set up a local dns cache like dnscache or BIND/named (default setting on freebsd is to run as local caching nameserver anyway).

It is highly preferable to use dnscache, since dnscache can be setup to listen for DNS queries on specific IP addresses (ie only on 127.0.0.1 only), whereas named unfortunately listens on all available interfaces (public as well as just loopback/127.0.0.1).

Alternatively if you're on windows you could just change your DNS servers by modifying the properties for your external network interface - just change the DNS servers to those which you know are updated more frequently than the default DNS servers your company uses.

Thanks for the info. I am on Windows, so the last thing you said is the most applicable in this case. That was actually my question . . . I know how to configure my connection to use a different DNS, but is there one other than my ISP's that I could use? Where would I find out about it? Anyway, it's kind of a moot point since I discovered the proxy server solution that does what I wanted and is very simple to setup and turn off when I don't need it any more.

About the proxy server . . . I found a list of what were listed as public proxy servers on a Russian website. I configured one of them in my browser and it worked fine, except when I tried to view certain pages I got a page saying that blah blah blah you are not allowed to view this page for such and such reason. As it turned out, the server belonged to some public school system and they had some kind of filtering scheme in place. (I'm not sure what they were filtering, exactly, because the URLs that it blocked were completely innocent -- it seemed arbitrary to me.) Anyway, do they know their server is being used that way? Did they intend for it to be? These probably seem like stupid questions, but the whole idea of using a "public" proxy server is pretty new to me.

>> public proxy servers on a Russian website.
Not this one was it: http://tools.rosinstrument.com/proxy/ ?
They used to have a decent setup going a few years ago but then started to charge for the privilege of using their databases (which didn't seem too well populated after a while).

Perhaps you answered your question yourself when you said in your original post:



Why not just use the hosting company's DNS servers?

No, it was www.samair.ru/proxy/. Seems like a pretty extensive list.

"Why not just use the hosting company's DNS servers?"

You'll have to excuse me -- while I get the general idea of DNS, I'm not that well informed about it. If I configure those DNS servers in my dialup adapter's TCP/IP setup, will those servers resolve my outgoing requests?

>> will those servers resolve my outgoing requests?
They should serve DNS requests for hosts they are authoratative for, but they may not necessarily serve DNS for domains they aren't authoratative for.

If you are working on the site www.example.com and the authoratative nameservers for example.com are ns1.example.com and ns2.example.com, then presuming the DNS data is maintained and configured correctly on ns1 and ns2, you should be able to enter ns1/2 as your DNS servers in the tcpip settings when you need to ensure you get up-to-date dns info about example.com. I think this is correct, although there may be circumstances where this does not hold.

At the end of the day, just try it out - if it works, all good. If it works only for example.com (ie you can browse to www.example.com but browsing to other domains fails for dns errors), then ns1/2 are probably only configured to act as non-recursive dns servers (ie they only answer queries about the domains they're auth for and do not return/cache DNS data for other domains). If it doesn't work at all (ie you can't browse at all for dns errors in your browser) then it's likely that the ns1/2 is down or there's a configuration problem.

If you have access to a shell you can query a dns server using dig:
dig @(ip address of nameserver for example.com) www

which would query the nameserver and ask for all information held for the hostname 'www' (www.example.com). This guarantees you get 'the word' on 'www' instead of just 'word of mouth'.


Another useful tool for windows - if you don't have access to a shell - is Sam Spade:
http://www.samspade.org/ssw/

This tool lets you run queries on nameservers iirc.

Good luck anyway,

Jez

OK, thanks for the info. The next time I find myself in a similar situation maybe I'll give that a shot. Maybe I'm misconceiving the situation, but it seems to me that it wouldn't be in a hosting company's best interests to just allow anyone to use their DNS servers to resolve arbitrary requests.

Re: dig, I mostly just use the utilities at centralops.net/co/ (e.g. Domain Dossier for DNS queries), but if I ever decide to get software to do it, I'll check out the program you mentioned.

My problem has never been an inability to get the current DNS data, just sometimes having to wait several days for my browser to get it due to my ISPs caching.