Author: James P. Roberts Date: To: Dave C. CC: exim-users Subject: Re: [Exim] Newbie SMTP/ISP-Problem ...
<snip> > > I run a small web and email hosting service. My ISP provides me
> > with a very small block of static IP's. I run my own DNS servers.
> > HOWEVER, I cannot get my ISP to properly delegate reverse
> > DNS lookups. (Huge sigh). A reverse DNS on my IP gets a
> > single valid response, which is some made-up name provided by
> > the ISP. With me so far?
>
> Yikes. Your ISP doesnt seem to be comnpetent to provide service then. I
> would keep pestering them until they get this right.
I agree, but Covad is the sole SDSL provider in the area. (There are
others, but they all contract out the actual connection to Covad). And
believe me, I HAVE pestered them, endlessly. When I get a few more
customers, (i.e. when I can afford it) I will move up to T1 service with
a REAL provider.
> BTW, there is an RFC on how to do delegations that dont align with a IP
> dot boundry. Search google for it and forward a copy to your ISP. Its
> about 5+ years old, long enough for any competent ISP to be able to
> support.
I know, and I did.
<snip> > Hopefully if you look up an MX for these domains, you get a host *name*
> which then has an A record with your IP address. IP addresses cannot go
> directly in MX records.
Yup. Sure do. Good point. I over-simplified my statements. MX records
for my hosted domains return my canonical server host name.
<snip> > The name of the server does not need to match the domain of the email
> addresses it handles.
Precisely the point I was trying to make. You said it much better than
I did, though.
<snip> >*Many* ISP's use lists of dynamic IP pools to block mail. If your IP's
>are listed in one of the lists of 'dynamic/dialup' blocks, and your IPs
>are NOT dynamic, you should contact the maintainer of that list and let
>them know. (Or possibly if your ISP provided that information to the
>list, ask your ISP to request that it be updated)
Not a dial-up, not using dynamic IPs, and I haven't encountered this
particular problem (yet). But your point is very valid.
> *Some* people running mailservers require the name you give in a HELO to
> resolve via a forard lookup to the IP address you are talking to them
> from. This shouldnt be that hard to do.
Not hard at all, and my server would pass this test.
> *Some* people running mailservers require the HELO name to match, AND
> require forward and reverse DNS for that name to match. Obviously you
> cant do this unless you can get your ISP to give you a handle on your
> in-addr lookups..
Precisely why I am unhappy with my ISP, and hope to upgrade. My point
here is mainly that many people do not have control over this, and thus
using it as a test to reject email is probably not a good idea.
> While I strongly support and recommend the first, I don't generally
> recommend the latter two.
>
> Regardless, if someone is choosing to make these requirements, then
> apparently its not important from them to receive mail from your or your
> customers.
