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I'm trying to use SMTP on localhost to send emails thru a simple mailform in c#. For some reason all emails end up on the badmail folder. The .BAD file says:

Final-Recipient: rfc822;
Action: failed
Status: 5.7.1
Diagnostic-Code: smtp;554 5.7.1 <IP>: Client host rejected: Sorry, no xDSL here

Anybody got any clue?


Okay, so my DSL connection is causing this. Anybody got a work around for that? thank you

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In time: gmail accepts all email sent by my localhost. This other paid server that blocks them. – Eduardo Mello Jan 6 '10 at 18:22
up vote 2 down vote accepted

One of the systems involved is identifying the sender-IP as belonging to some kind of ISP address pool, most likely one that serves DSL customers.

If it is your system doing the rejecting (unlikely) then you need to change your mailer so that it doesn't use the DSL blacklists.

If it is the system you are trying to relay to that is doing the complaining (more likely), then you either need to contact them to plead your case (which is unlikely to get anywhere) or figure out another way to relay email to them. If you are on a DSL pool of some kind, your ISP almost certainly has a relay that you can use after you authenticate with them.

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I'm sending from a localhost. My IP is dynamic, if i have a fixed IP, would it make any difference? thank you – Eduardo Mello Jan 6 '10 at 18:21
Blacklists don't operate on outgoing email, they operate on incoming email. And yes, if you had a static ip address you would most likely not have this problem. – joeqwerty Jan 7 '10 at 13:23
Yes, but email which is outgoing here is incoming on the far side, which is where the rejection is happening -- before the remote side accepts the message. This makes the bounce appear to be generated by the local side, when in fact it is a rejection by the far side that causes the problem. And while a static IP may improve matters, it isn't a surefire cure -- I've had some blacklists smear me because once-upon-a-time there was allegedly DSL clients on this block. – David Mackintosh Jan 7 '10 at 15:03

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