Router and reverse DNS

Discussion in 'privacy general' started by ambolu, Sep 30, 2006.

Thread Status:
Not open for further replies.
  1. ambolu

    ambolu Registered Member

    Joined:
    Apr 8, 2006
    Posts:
    14
    I'm new to all this router thing, how do I disable reverse dns? What do I have to look for in the router configuration?

    I have done it once by accident and reset it because I thought disabling it was bad. Now I learned that disabling is good.
     
  2. spm

    spm Registered Member

    Joined:
    Dec 9, 2002
    Posts:
    437
    Location:
    U.K.
    Reverse DNS (rDNS) has nothing to do with your router. rDNS, when present, consists of a 'PTR' DNS record held wherever the relevant domain's DNS records are held, and it allows the lookup of a domain name from an IP address.

    The main use of rDNS is for mail servers or, more correctly, Mail Transfer Agents (MTAs), to be identified by other MTAs when transferring email messages, as part of anti-spam measures. AOL and many other MTAs will not accept mail from MTAs which do not have an appropriate rDNS set up.

    If rDNS is of relevance to you and for some reason you want it disabled for your connection, speak to your ISP.
     
  3. ambolu

    ambolu Registered Member

    Joined:
    Apr 8, 2006
    Posts:
    14
    strange. I managed to disabled last time without contacting anyone.

    Normally when you visit a site your IP is logged and they can get your ISP through your IP by doing a reverse DNS? Like ShieldUP for example. Right after I did something to my router ShieldUP can only detects my IP and that's all it knows. My ISP domain was not showned...

    Before:

    linespeed-127-0-0-1.*.makeupdomain.com

    after:

    127.0.0.1 (just a make up IP)
     
  4. spm

    spm Registered Member

    Joined:
    Dec 9, 2002
    Posts:
    437
    Location:
    U.K.
    Well, the ShieldsUp report you allude to is basically a piece of tosh. If ShieldsUp (or anyone else) can see your router's external IP - and that is the usual case - then a rDNS lookup will succeed (or not, depending on whether your ISP maintains a rDNS record) irrespective of how you configure your router. To be fair to grc, the ShieldsUp report does admit that you can't change it.

    If you are concerned that your IP address is visible to web sites you visit - it is, but hey, so what? - then use an anonymising service.
     
  5. ambolu

    ambolu Registered Member

    Joined:
    Apr 8, 2006
    Posts:
    14
    "Reverse DNS is the process of using DNS to translate IP addresses to hostnames."

    This should tells you that it doesn't matter whether your IP is dynamic or not because by doing a reverse DNS on your IP they can find out your ISP (hostname).

    By disabling this thing (not sure if you can but I somehow did it last time) they cannot detect your hostname, they can only see your IP. Once disabled I can reconnect to get different IPs and they won't know that they all come from the same hostname.

    I hope i got that right. :)
     
  6. spm

    spm Registered Member

    Joined:
    Dec 9, 2002
    Posts:
    437
    Location:
    U.K.
    Like I said, the grc report is a heap of proverbial. If you have a dynamic IP address, your 'hostname' will change every time your IP address changes anyway. What is it you think your 'hostname' is, anyway??

    rDNS has nothing whatever to do with determining who your ISP is. It doesn't matter whether you have an rDNS record or not - IP ranges are allocated to ISPs, and irrespective of what IP you are allocated (from your ISP's range), your ISP remains the same. Try doing a WHOIS lookup on your current (external) IP address, then when your IP address next changes, do another. And so on. The WHOIS record for your IP will still indicate the same ISP.
     
Loading...
Thread Status:
Not open for further replies.