Re: SPF = Sender Policy Framework (was: Microsoft spam solution<snip>)

From: Randolf Richardson (rr_at_8x.ca)
Date: 09/20/04 

Date: Mon, 20 Sep 2004 06:13:09 GMT

"Dave Uhring <daveuhring@yahoo.com>" wrote in news.admin.net-abuse.email:

> On Mon, 20 Sep 2004 05:02:55 +0000, Randolf Richardson wrote:
>
>> Regardless of how I configure my DNS zone to return a different IP
>> address for "netware.inter-corporate.com," the root servers will
>> override this by providing the information specified in the host
>> record. This also seems to speed up DNS resolutiona little bit, by the
>> way, because the root servers don't have to take addition steps to look
>> up external NS records.
>
> I also think that someone is putting something over on you:
>
> Non-authoritative answer:
> Name: netware.inter-corporate.com
> Address: 24.87.56.253
>
> Authoritative answers can be found from:
> inter-corporate.com nameserver = netware.inter-corporate.com.
> inter-corporate.com nameserver = oc48.inter-corporate.com.
> inter-corporate.com nameserver = fast01.inter-corporate.com.
> oc48.inter-corporate.com internet address = 64.251.89.8
> fast01.inter-corporate.com internet address = 64.251.89.88
>
> Suppose you turn off those three DNS servers and then attempt to resolve
> some host whose zone records are maintained there.

            I'm aware of how this is all configured. Of course, if I turn off my
DNS servers and wait for caches to expire, the only items that will resolve
are the registered name servers.

            I know it works this way too because I've run across a few registered
host names that resolved in the past, yet the IPs they resolved to weren't
running any DNS servers (queries against them simply timed out). The only
reason I discovered these was when I was troubleshooting eMail delivery
problems for clients. 

-- 
Randolf Richardson, pro-active spam fighter - rr@8x.ca
Vancouver, British Columbia, Canada
Please do not eMail me directly when responding to my
postings in the newsgroups.
Sending eMail to other SMTP servers is a privilege.

Relevant Pages

  • Re: CEICW after loading third party certificate
    ... I've been known to disagree with Dr Tom however, yes, the one remaining part of the puzzle is DNS in/outside the LAN. ... ISA, unlike most commodity routers, doesn't really care if references to ourname.domain.com resolve to its internal or external IP. ... The requests will be handed to ISA anyway and processed through forward/reverse proxy by the actions of the ISA Firewall Client, which should be on all ISA client PCs. ... So we create a DNS ZONE (not host) for ourname.domain.com to point to the IP address. ...
    (microsoft.public.windows.server.sbs)
  • Name resolution in .Net - arrrrrggghhhh!
    ... "The Resolve method queries a DNS server for the IP address associated ... "When hostName is a DNS-style host name associated with multiple IP ... documentation, ...
    (microsoft.public.dotnet.languages.csharp)
  • Re: RPC Service Unavailable
    ... Host address: 172.16.0.0 (This is a network, ... If you have 2 DNS servers use itself as preferred and the other as secondary with there "real" 172.x.x.x address. ...
    (microsoft.public.windows.server.active_directory)
  • Re: MX-only domains dying?
    ... I've always thought of the www host as being an artifact of the good old days of the web where DNS was used as part of the maintenance methodology - if you needed to service a box you switched the IP in DNS to the hot spare. ... Using service names allows you to have each respective serviceresolve to different address, thus allowing you to spread services across different hosts. ... If you are wondering why I have A records for domainN.tld verses a CNAME record, I have never been able to get CNAME records to co-exist with any other record type for a given name. ...
    (comp.mail.sendmail)
  • Re: Prevent Caching of real world domain in W2K3 sp1 DNS.
    ... resolve anything usda.gov on either of my main DNS servers. ... and the cache is quite full. ...
    (microsoft.public.windows.server.dns)