Hello, Just wanted to thank everyone for their responses. I called my ISP today and they set up the reverse DNS without any teeth pulling involved. Thanks!!!! > -----Original Message----- > From: centos-bounces at centos.org > [mailto:centos-bounces at centos.org] On Behalf Of Tom Diehl > Sent: Monday, June 26, 2006 3:36 PM > To: CentOS mailing list > Subject: [CentOS] Re: DNS Server > > On Mon, 26 Jun 2006, Paul wrote: > > > On Mon, June 26, 2006 7:47 am, Johnny Hughes wrote: > >> On Mon, 2006-06-26 at 07:38 -0400, Thomas E Dukes wrote: > >>> > >>>> -----Original Message----- > >>>> From: centos-bounces at centos.org > >>>> [mailto:centos-bounces at centos.org] On Behalf Of Johnny Hughes > >>>> Sent: Monday, June 26, 2006 7:19 AM > >>>> To: CentOS ML > >>>> Subject: RE: [CentOS] Re: DNS Server > >>>> > >>>> On Sun, 2006-06-25 at 20:32 -0400, Thomas E Dukes wrote: > >>>> <snip> > >>>> > >>>>> > >>>>> So even if a service such as zoneedit, say they can do > >>>> reverse DNS, it > >>>>> won't work? > >>>>> > >>>>> I really don't understand how it can work in one direction > >>>> and not the > >>>>> reverse. If they can keep up with my IP address and > match it to > >>>>> my domainanme, seems they could do the reverse. > >>>>> > >>>> > >>>> OK ... rather than you staying confused on this issue, I > will try > >>>> to explain it in basic terms. > >>>> > >>>> DNS converts names to IPs (forward lookups) and IPs to names > >>>> (reverse lookups). > >>>> > >>>> A forward lookup is when you have a name > (www.abcxyz.com) and need > >>>> a number. This this case, there is a domain owner and > that domain > >>>> has it's own DNS Zone. The owner of that Zone can put > whatever IP > >>>> addresses > >>>> (numbers) with names that they want in that zone. > >>>> > >>>> In the case of a forward lookup, there is no predefined > zone at all > >>>> ... > >>>> you can have as many names as you want, and since people > pay for it > >>>> (the name), it stands to reason that will keep it > updated properly. > >>>> > >>>> A reverse lookup is different. The standard for reverse lookups > >>>> break them down in "Class C" blocks (that is, the first > 3 groups of > >>>> numbers are the network number, the last group is the > host number). > >>>> If you have an ip address of: > >>>> > >>>> 192.87.99.234 > >>>> > >>>> The network number is 192.87.99.0, the subnet mask is > >>>> 255.255.255.0, the host number is 234, and the reverse lookup > >>>> domain is: > >>>> > >>>> 99.87.192.in-addr.arpa > >>>> > >>>> All 254 host addresses in that zone are normally > assigned from the > >>>> owner of that zone from one machine. If someone buys the whole > >>>> class C network, they get to control the zone, otherwise it is > >>>> normally controlled by the ISP that owns all the IPs. > >>>> > >>>> It is possible, but not usually done, to break up the > reverse into > >>>> smaller ranges. > >>>> > >>>> Tom Diehl has already mentioned RFC 2317: > >>>> > >>>> http://www.faqs.org/rfcs/rfc2317.html > >>>> > >>>> Using the techniques there, an ISP _CAN_ transfer > control of some > >>>> reverse lookup domains. They will normally not do it unless you > >>>> have a fairly large network, however. > >>>> > >>>> I hope this helps you understand that forward zones are > designed to > >>>> easily break them down into 1 or 2 names ... but reverse > zones are > >>>> predefined and not designed for less than 1 class C > network blocks. > >>> > >>> Hello Johnny, > >>> > >>> I guess that makes sense. It seems it would create too much work > >>> for the ISP to handle the reverse lookup for a single IP. > If they > >>> dole them out that way, they should either do it or delegate them. > >>> > >>> All this is to operate a mail server without bounces. Is > this why > >>> it recommedned to use your ISP's mail server as smarthost? Does > >>> this mean I would be using the ISP's mail server for > outgoing mail? > >>> Or is it just 'stamped' with the ISP's name to prevent bounces? > >>> > >>> Thanks, > >>> > >>> Eddie > >> > >> Most ISPs block outbound port 25 traffic now ... only > allowing mail > >> server operation (or even normal sending of e-mail via a > client) to > >> be done out of their mail servers. > >> > >> I had, for many years, run a mail server on my linux box at home. > >> Spammers (and viruses) have ruined that option for us. I > now have a > >> domain that I use for e-mail at a hosting provider, as too many > >> servers now block dynamic ranges and cable/dsl ranges to > combat spam. > >> > >> I have since just setup an NX desktop and use that to get > to my mail > >> at my home desktop when I am not there ... which seems to work OK. > > > > There are a select few ISP's still home-server friendly, one being > > Speakeasy.net. > > +1 for Speakeasy. They also have a very active abuse desk. > > Regards, > > Tom > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos >