RE: Not receiving some inbound emails

Yours is a logical problem.

Two things come to my mind

1. You have a mail firewall that has blacklisted those domains. If you do
have a mail filter i would say check that. ISP's can block/filter certain
domains that they think are sending SPAM e.g a company that sends out
newsltters to clients who are hosted by the same ISP will have your domain
sending the same email to say 50 + recepients which can trigger SPAM filters.
Once thats done you are blaclisted or they are blacklisted.

I would say get some1 from a domain in que to send email to some1 @ your ISP
and see if goes through. If it doenst means ISP blocking them not you.

2. Routing. Get someone from the domains that cant send you email to telnet
onto port 25 on your email server ip address. if they cant you have a routing
issue, maybe a loop? It would help if your email server can allow you to view
SMTP session in real time along with originating IP address so you can see
the telnet session on 25 coming through. If you cant see the testing domain's
IP coming through its simply an IP routing issue.

Hope this helps

"Roland" wrote:

> Some our users began recently complaining that some emails sent to them never
> arrive. The sender then would receive first a delay notification, than an
> NDR. This happens to emils sent from certain domains. When the same emails
> are sent to Hotmail or other free account, they arrive immediately, but not
> at our Exchange. All traffic goes (at least it should) though the relay
> server at our ISP: Exchange uses it as a smart host, in DNS it has much
> higher priority than Exchange.
> I have a feeling that it has to do something with the Exchange. Our
> configuration: Windows 2003 Standard SP1 all latest patches, Exchange 2003
> with all latest patches, Symantec Antivirus for Exchange. Email traffic goes
> through DMZ set up with two ISA servers (2004 and 2000).
> Any ideas?
.

Relevant Pages

  • Re: Spam attack from within, please help!!!
    ... queue, I deleted all, applied SP2 ... I've heard of a product from Symantec that sits on top of an exchange server ... additional SMTP vs instead, set only anonymous authentication and do not ... Adaware on my email server and both reported clean results. ...
    (microsoft.public.exchange.connectivity)
  • SMTP will not connect
    ... I just got WIN2003 SBS and I cannot get exchange to be a real email server. ... Windows cannot query for the list of Group Policy objects. ... which tells me it might be a MS firewall issue. ...
    (microsoft.public.exchange2000.admin)
  • RE: #5.5.0 smtp; 571 Delivery not authorized, message refused
    ... (i.e. Trend Micro Messaging Security, McAfee GroupSheild, Symantec ... is" there was a SMTP communication problem with the recipient's email server. ... Both of us use Exchange 2003. ...
    (microsoft.public.exchange.admin)
  • Re: Exchange Migration
    ... > We plan to migrate from our email system, IMail, to Exchange 2003 later ... > email on our current email server, they both share the same email domain. ... Now can we host ... > accounts in our domain for them to have a mailbox. ...
    (microsoft.public.exchange.setup)
  • Re: my isa server becomes a spammer?
    ... > It looks like what you are seeing are NDRs (non-delivery reports) ... If you have an Exchange server, ... hoping some will match names on your email server. ... This is an NDR, non-delivery report. ...
    (microsoft.public.isaserver)
Loading