opendns

[Johnny248]

Can anyone really tell me if I want to be using this or not? my router is configured to use OpenDNS, but I'm not sure if I should use it, or my normal ip dns?

Not a network guru, someone told me I should run it so I tried it and it seems to work fine. I just don't really know the advantages/disadvantages

 

[Colt45ws]

Does not really matter. If you want, you can sign up at the openDNS site, and set it up to block web content categories for example if you have children you do not want seeing the nasty stuff on the web and what not.

 

[Quattro Pete]

Such service is only needed if you need to access some server inside your home LAN from the outside and you don't want to worry about your external IP address changing. Most of the residential Internet services have a dynamically assigned IP (as opposed to static IP). So if that IP were to suddenly change, you would not know how to access your local resources from outside. With a service like OpenDNS, you just use a domain name instead of the actual IP address, and the domain name always remains constant.

 

[Quattro Pete]

Oh wait, please disregard. I thought this was like no-IP (dynamic DNS) type service.

 

[Johnny248]

ok, so I changed the DSN address in my linksys router to what OpenDNS said to do. Now, how do I put it back to normal?

 

[JustinH]

Originally Posted By: Jdblya
ok, so I changed the DSN address in my linksys router to what OpenDNS said to do. Now, how do I put it back to normal?


Either way, you aren't going to get much of a change. I like OpenDNS, and have used it for years. It was a little more reliable then my ISP's DNS server.

To change it back, change the static dns server addresses that you set back to the "assigned by isp" values, or automatic..

 

[uc50ic4more]

I've used OpenDNS for a few years now. I do not really notice any kind of speed difference over and above my ISP's DNS, but I *do* notice that on the few occasions that I've moved one of my web site client's servers, OpenDNS has had the new information updated much faster than my or any other ISP I've measured.

OpenDNS, if you establish an account there, also offers some really handy filtering options for adult and other questionable content. It's nice to set that up and let them maintain and enforce the filtering rules instead of you having to manually keep IP and domain rules for each computer in your house updated.

 

[eljefino]

I've had flaky DNS service from roadrunner and been glad I used OpenDNS. If I hadn't had their IP #s already programmed in, I would have had no way of finding and retrieving them.

The "helpful" error page that comes up if something cannot be found differs between them and your regular ISP.

 

[simple_gifts]

uc, I am surprised you do not have a caching dns server. A definite tweak for linux users.

http://embraceubuntu.com/2006/08/02/local-dns-cache-for-faster-browsing/

 

[Familyguy]

I run my own primary and secondary DNS servers. But when I'm somewhere that I can't use them, I use OpenDNS.

 

[uc50ic4more]

Originally Posted By: simple_gifts
uc, I am surprised you do not have a caching dns server. A definite tweak for linux users.

http://embraceubuntu.com/2006/08/02/local-dns-cache-for-faster-browsing/


Point taken, although I'd been put off of doing this for the following reasons; some of which are more valid than others:

1) My primary concern regarding DNS has always been my ability to administer systems for friends/ family/ clients/ neighbours. I have everyone signed up at dyndns.com, but had always wanted to run my own dynamic DNS server so that my friends/ family/ clients/ neighbours systems would report their IP to *me* rather than a third party. To do that, as far as my research indicated, however, meant running a *full* DNS server like bind, which would mean terrible bandwidth and resource requirements that are beyond the scope of my needs. For that reason, I guess I'd always equated DNS server with excessive bandwidth.

2) dnsmasq was the only DNS caching application I was aware of, and what put me off of that is that the cached queries were in RAM, meaning that all of that caching was *per session*, which means that the initial DNS query per session is still going through an external DNS server. In the comments of the article at the URL you supplied, though, was mention of an alternate caching application called pdnsd which looks promising. I am going to check to see if it's in the Debian repositories as soon as I hit "Submit" on this post.

3) Although not nearly a true substitue for a proper DNS cache, I do have a few spots "hard wired", for lack of a better term, in my /etc/hosts file. this is as much to provide me with some convenient aliases than to cache DNS information.

 

[Colt45ws]

I use bind to do my DNS caching along with Squid to do HTTP caching with a port REDIRECT in iptables to make it invisible to other people in the house. (No configuration changes on their end, proxying just happens.)

 

[javacontour]

How much bandwidth do you think DNS uses?

Unless you are doing zone transfers, I can't see bind or any other DNS implementation using gobs of bandwidth.

I've run a caching server in my home when I was on dial up, so the caching server would keep the record as long at it was still "fresh" (the TTL)

I didn't experience bandwidth to the outside world being gobbled up.

I suspect the same would be true for someone running their own personal domain of family and friends.

I guess I don't understand the concern about bind or anything else using lots of bandwidth, what am I missing?

 

[uc50ic4more]

Originally Posted By: javacontour
How much bandwidth do you think DNS uses?


If you're running a DNS server that needs to remain abreast of DNS name change propagation, I'd expect you'd need a heck of a lot of bandwidth. When I think of how many gazillion times an hour someone's domain or other alias changes IP on this planet of ours.........

 

[javacontour]

bind only keeps track of it's own zones and any zones it's cached.

It will keep cached records based on the ZOA's published TTA.

A caching server doesn't go out and learn every zone out there. It knows the root level servers and caches everything it learns based on queries it fields from it's clients.

It doesn't check anything cached unless it expires and a client asks for that information again.

I could see it being slower for servers who use a round-robin'ing (my term) DNS server to do load balancing. I.E. the DNS server passes out different addresses for each query in some sort of even distribution.

However, even for that to work, the record has to have some sort of shelf life, or you'll get time outs during web sessions.

Unless of course if you go to www.mysite.com and the first thing it does is redirect you to wwN.mysite.com, where N is one of N webservers that share the load.

But again, the big bandwidth is zone transfers and if you are not trusted by the ZOA, you are not going to get an entire zone transfer sent to your nameserver.

A caching server is seeded with the root level servers and remembers what it's asked for, and little if not nothing more.

 

[javacontour]

Now if your server is the ZOA, then you may have some updates and secondary servers will need zone transfers.

But again, I got the impression we were talking about dozens, maybe 100 records.

A web page likely contains more information than such a small zone.

It may be busy inside a busy enterprise that updates DNS based on DHCP assignments. But I don't think we are talking about that level of traffic here either.