Reverse DNS
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Thread: Reverse DNS

  1. #1
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    Reverse DNS

    I've been doing some research on reverse DNS, and I think I understand most concepts of it, but I am still a little bit confused. I was wondering if someone could help clear this up for me.

    I have a few IP Addresses that I purchased off of my ISP. I have a DNS box running that currently is handling the Forward DNS for my domain names and web sites I am hosting. If you do a nslookup on the IP Addresses it still lists my ISP as the host. From what I understand, correct me if I am wrong, if I setup Reverse DNS on my DNS box I should be able to be listed as the host for these IP Addresses. I messed around a little with my DNS box, but when I do a nslookup on the IPs it still gives my ISP as the host.

    I have stumbled across some documentation on reverse dns but I am still a little confused about it. Some say that I have to contact my Upstream and then they can set it up so it looks at my DNS server when queries are done on the IP. I'm not sure how that works, but before I even get that far is there a way that I can lookup the IP address through my DNS box using some kind of nslookup command to at least tell if it is setup right on my end?

    Also after that any suggestions where to go from there would be appreciated. Any experiences, or links on this to share would also be cool. If it helps at all, I am using Windows 2000 Server's DNS.

    Thanks for any info.
    An Ounce of Prevention is Worth a Pound of Cure...
     

  2. #2
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    i cant say this for sure, but i think that its listing the IP address as your ISPs cause THEY registered it for them (did you buy 2 or 3 single IPs or a whole class c network address?) if you just took one of their fixed IP addresses that they give you for your dial in then that is still their address on their network. if you bought your own class c network then it would be listed as you and not them........ but then again i dont know which one you did so...... help any?

  3. #3
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    I have 4 static IP Addresses from these guys, and I will be purchasing more in the future. It is a always up DSL connection that I have a web server hosting a few sites, and a dns server on. The forward DNS works fine and the domain namess are associated with the IP addresses no problem.

    If you do a nslookup on the IP address it still lists my ISP as the host. Most of the documentation I have read covers class c subnets when it comes to reverse DNS. What I am wondering is if I can have the IP addresses I purchased point at me as the host by using my reverse DNS. If that is even possible I think I have to contact my ISP and have them point those IP addresses to my DNS machine.

    A good link I found on this that explains how the basics of reverse dns all work is:
    http://www.stamey.nu/DNS/HowReverseLookupWorks.asp

    Any information?
    An Ounce of Prevention is Worth a Pound of Cure...
     

  4. #4
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    ok yeah, thats what i thought you may have done. the whole class c (or b depending on the ISP) network (all x.x.x.0-255) is registered to your ISP, not you. thats why its not showing up as your name. you didnt purchase the IP addressed, you put a contract on the IPs sothat you have a static ip for your server. so basicly as lond as you pay the bill its your IP, but if you slip on the bill they take it away and dive it to someone else that wants a static IP. so basicly its like a phone number, the number (IP address) does to your house (server) and talks to you (your webserver and all other data you wanna give out) but the actual phone number is owned by the fone company that leases the line to you. the same principal is also for this IPaddress. they own your x.x.x.5 ip address even tho it points to your server. what you are wanting to do is get a registered network of your own. basicly by regertering you get your own IP network on the internet (simply you get x.x.x.0-255) and THIS will point to you. now this is diferent from DNS, DNS is a way to translate web assresses that we as umans can remember to an IP address that the puters use. inother words www.hotmail.com goes to a spacific IP address. your web address will be in your name (if you have one) but the IP is in your ISPs name cause you are borrowing their IP and its not yours really (like all the phone lines and equipment for that)

    dose that explain it better?

  5. #5
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    Well, most of the time, ISPs won't delegate DNS for anything less than an entire class C to you; it's simply too painful to maintain. But, often, if you call them, they'll maintain the records the way you want them to... however, DSL providers for residential customers are almost always against this sort of thing and often just advertise proper DNS to ensure that double-reverse lookups work for their entire list of subnets and leave it at that...

    If you can get them to do it (and still want to), let me know and I can help you help them get it setup, if necessary.

    I will make one disclaimer, however: running a DNS server that is public to the Internet is one of the bigger security risks out there that I know of (I am fairly sure that it's been in the "top 10 risks" literally since the time that SANS started publishing such things); in any case, it should not be taken lightly, if you choose to do it.
    \"Windows has detected that a gnat has farted in the general vicinity. You must reboot for changes to take affect. Reboot now?\"

  6. #6
    Junior Member illv's Avatar
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    your isp has that problem with the reverse lookup.

    illv //
    illv // seen the digital world from monochrome dial up to what it is today.

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