On Mon, 15 Sep 2003 18:23:46 -0400 "Michael W. Cocke" <[EMAIL PROTECTED]> wrote:
> On Mon, 15 Sep 2003 13:39:18 -0500, you wrote:
>
> >On Mon, 2003-09-15 at 08:13, Michael W. Cocke wrote:
> >[snip]
> >
> >> Pardon me while I expose my ignorance. What's a smarthost, and given
> >> me by which provider? All I get from my so-called ISP is a wire with
> >> an IP address, or do you mean dyndns?
> >[snip]
> >
> >Your ISP has an smtp server no?
> >
> >That is the smarthost.
...
> >What this does is tells your SMTP server to relay all messages through
> >your ISPs mail server.
>
> Ahhhh. That explains why I never heard of it. My ISP might run an
> smtp server, but you couldn't prove it by me, and I don't have access
> to it. I run sendmail 8.12.8 locally. Thanks for the info though.
Try
nslookup -q=mx <your ISP's domain name>
Example #1 (mail to io.com; MX records):
$ nslookup -q=mx io.com
Server: soyokaze
Address: 0.0.0.0
Non-authoritative answer:
io.com preference = 10, mail exchanger = mx.io.com
io.com preference = 20, mail exchanger = rbl.io.com
io.com preference = 30, mail exchanger = mx2.io.com
io.com preference = 40, mail exchanger = mx3.io.com
Authoritative answers can be found from:
io.com nameserver = ns3.io.com
io.com nameserver = ns1.io.com
io.com nameserver = ns2.io.com
mx.io.com internet address = 199.170.88.107
rbl.io.com internet address = 199.170.88.17
mx2.io.com internet address = 199.170.88.20
mx3.io.com internet address = 199.170.88.72
# Mail sent to io.com is directed first to lowest-preference MX, which is
# mx.io.com [199.170.88.107]. If it's not available, mail is delivered to
# the next-lowest-preference MX until it's accepted or until we run out
# of MXs to try.
If you were an IO customer, you'd smarthost through mx.io.com.
Example #2 (no MX record, fallback to A record):
$ nslookup -q=mx catherders.com
Server: soyokaze
Address: 0.0.0.0
catherders.com
origin = ns1.mydyndns.org
mail addr = zone-admin.dyndns.org
serial = 2003082805
refresh = 10800 (3H)
retry = 1800 (30M)
expire = 604800 (1W)
minimum ttl = 1800 (30M)
# No MX record; lookup A record:
$ nslookup -q=a catherders.com
Server: soyokaze
Address: 0.0.0.0
Name: catherders.com
Address: 67.84.195.3
# Mail to catherders.com gets delivered to 67.84.195.3
> If anyone using AOL needs to hear from me, I'll tell them to complain
> to whatever AOL genius decided that this would be a good anti-spam
> measure.
No offense, but this technique blocks metric assloads of spam with
almost no FPs.
You've got a fairly dodgy setup and as abuse resistant and responsive as
your systems may be (and trust me, I've been in the same boat), nobody
is going to bat an eye at blocking mail originating from servers
operating from dynamically-allocated network space. Now if AOL was
blocking mail based only on mismatched rDNS from known static address
pools and changed their whitelisting policy from minute to minute, I
might have some sympathy. Dynamic IP space is a cesspit of spammers,
open proxies, and infected hosts. No responsible admin will naively
accept mail from these networks and no clueful customer should expect
otherwise.
Your options are a) smarthost, or b) get a static allocation with proper
DNS (forward and reverse) and current domain and SWIP contact info. Make
sure your mail server sends a FQDN as its HELO greeting and that your
<abuse>, <postmaster>, and <security> role accounts work properly (see
http://www.faqs.org/rfcs/rfc2142.html)
Sorry to be harsh, but spammers, clueless proxy authors and users, and
vulnerable Windows boxes have made this policy necessary and the best
you can do is to move your servers or route your mail through more
legitimate-looking channels. This will require more effort on your part;
take heart that you're learning a valuable technical skill in the
process. :/
-- Bob
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