iis smtp nntp: How can I fix error 4000 - host dropped connection? -- iis smtp nntp

How can I fix error 4000 - host dropped connection?

a165287 NO[at]SPAM yahoo.com
7/31/2004 1:28:47 PM

iis smtp nntp: Hi,

For web development purposes, I've installed SMTP service on my
Windows 2000 Pro workstation. I configured it to the best of my
knowledge (read 'none') and then tried it by dropping an RFC822
conformant message into the Pickup folder. Here's the message itself
(this post uses fake domains: the real thing uses valid, tested
addresses)

From: myself@mycooldomain.com
To: mybuddy@someisp.net
Subject: As basic as it gets

This is the plain text body of the message.

But the message ends up stuck in the Queue folder. I checked the
Windows event log - and found a '4000' error that said the remote host
dropped the connection. I retried my message by addressing it
different 'from' and 'to' addresses. Same result.

I've searched the internet high and low and most answers are
incomprehensible to me. I did enable 'relaying' from my machine but
other than that, I'm stuck. I'm really not familiar with all those DNS
and MX and TCP packets or whatever. I do have a network card installed
(came with the computer) but I don't have a network, this is my home
machine. I connect to the net via dialup modem. Do I need to change
anything in my DUN or Network stuff? My Internet apps are working just
fine (sending and receiving mail, browsing). I'm always testing when
connected. Some people say this means my ISP is 'blocking port 25' --
I'm not sure what they mean by that :(

If you could please explain in newbie terms what is happening and how
to solve it, I'd be eternally grateful. If you need more info or for

Re: How can I fix error 4000 - host dropped connection?

a165287 NO[at]SPAM yahoo.com
7/31/2004 10:08:59 PM

Hi everyone,
I'm happy to report that the issue has been resolved. I specified a
'smart host' which is my isp's SMTP server... I'm not sure why it
works but if anybody gets the same error, you can give it a try.

Thanks for reading.

[quoted text, click to view]

Re: How can I fix error 4000 - host dropped connection?

Toby Herring
8/1/2004 9:53:02 AM

There are several possible causes, but many/most of them fall into a single
category: The remote mail server thinks you're a spam host.

My mail server is set up to automatically reject connections from:
- The IP address is black-listed in one of the DNSBL's
- dynamic IP addresses (dial-up IP's, cable-modem IP's, residential ADSL
IP's, etc) This actually falls under one of the DNSBL's
- IP addresses that fail a reverse lookup (i.e. I can't look up the IP
address PTR record and get a valid FQDN in response.)
- A host that fails any one of the simple tests designed to check whether a
remote host is probably an open relay.

I would say that most likely your mail server is failing one of the above,
but your ISP's server that you're using as a smart relay doesn't fail any of
them. The smart host allows you to send with no restrictions, however,
because you're on their network, and your IP address is "trusted" by their
server.

You should also note that you may still get some failures from the above
tests. My server (and I assume many others) perform these tests on EVERY
server in the "relay chain," not just the one that finally connects to my
server.

--
Toby Herring
MCDBA, MCSD, MCP+SB

[quoted text, click to view]

Got something to say? Click here to post a reply to this thread.

Don't see what you're looking for? Try a search.

View other messages in the iis smtp nntp group.