I have a CentOS 5 machine at home, behind a NAT gateway. Among other things, I'm running mdadm in monitor mode to alert me to RAID failures. I want it to send messages to my main email address. Any messages I send from the home CentOS box to that email address are being rejected with this error:
Deferred: 451 Could not complete sender verify callout
My understanding is that the destination mail server is trying to connect back to the source email host via SMTP as an anti-spam check and is failing.
My external IP is set up with a dynamic DNS entry, so I guess I could set up an MX record and actually receive mail on the home box, but I don't want to deal with the security issues or the spam.
Any suggestions for allowing sendmail-dependent apps running on the home machine to be able to send mail?
Thanks.
-Pete
Peter Loron wrote:
I have a CentOS 5 machine at home, behind a NAT gateway. Among other things, I'm running mdadm in monitor mode to alert me to RAID failures. I want it to send messages to my main email address. Any messages I send from the home CentOS box to that email address are being rejected with this error:
Deferred: 451 Could not complete sender verify callout
This is not sendmail failing.
My understanding is that the destination mail server is trying to connect back to the source email host via SMTP as an anti-spam check and is failing.
My external IP is set up with a dynamic DNS entry, so I guess I could set up an MX record and actually receive mail on the home box, but I don't want to deal with the security issues or the spam.
Any suggestions for allowing sendmail-dependent apps running on the home machine to be able to send mail?
Nothing to do with your ip. Just use an email address that Google can verify and again, it has NOTHING to do with sendmail.
Peter Loron wrote:
I have a CentOS 5 machine at home, behind a NAT gateway. Among other things, I'm running mdadm in monitor mode to alert me to RAID failures. I want it to send messages to my main email address. Any messages I send from the home CentOS box to that email address are being rejected with this error:
Deferred: 451 Could not complete sender verify callout
My understanding is that the destination mail server is trying to connect back to the source email host via SMTP as an anti-spam check and is failing.
My external IP is set up with a dynamic DNS entry, so I guess I could set up an MX record and actually receive mail on the home box, but I don't want to deal with the security issues or the spam.
Any suggestions for allowing sendmail-dependent apps running on the home machine to be able to send mail?
configure your sendmail to use your ISP's mail server as a 'smarthost'.
Christopher Chan wrote:
configure your sendmail to use your ISP's mail server as a 'smarthost'.
How is that going to help the dest mta verify his address?
it won't have to. his ISP will accept mail from its own customer's IP address, same as if they were end user mail clients, and it will relay for him. the destination MTA will presumably accept mail from his ISP's mail server, unless they are a known spammer.
John R Pierce wrote:
Christopher Chan wrote:
configure your sendmail to use your ISP's mail server as a 'smarthost'.
How is that going to help the dest mta verify his address?
it won't have to. his ISP will accept mail from its own customer's IP address, same as if they were end user mail clients, and it will relay for him. the destination MTA will presumably accept mail from his ISP's mail server, unless they are a known spammer.
The dest mta is most probably doing a blank sender address verify on all emails. Although running a mail server on a dynamic ip is discouraged and use of the ISP's relay box is encouraged, I doubt that in this case that it will make any difference unless the dest mta has the ISP's ip(s) whitelisted which I doubt every much. The solution is to use a verifiable returnpath with bonus points for setting DS.
Christopher Chan wrote:
The dest mta is most probably doing a blank sender address verify on all emails. Although running a mail server on a dynamic ip is discouraged and use of the ISP's relay box is encouraged, I doubt that in this case that it will make any difference unless the dest mta has the ISP's ip(s) whitelisted which I doubt every much. The solution is to use a verifiable returnpath with bonus points for setting DS.
well, he'll need to configure his script to specify a valid FROM address, is that what you mean? it might require configuring his local sendmail to masquerade all outbound mail as whatever 'real' domainname he uses for email, like, peterl@standingwave.org ...
On Tue, 2007-11-06 at 23:59 -0800, John R Pierce wrote:
Christopher Chan wrote:
configure your sendmail to use your ISP's mail server as a 'smarthost'.
How is that going to help the dest mta verify his address?
it won't have to. his ISP will accept mail from its own customer's IP address, same as if they were end user mail clients, and it will relay for him. the destination MTA will presumably accept mail from his ISP's mail server, unless they are a known spammer.
Thanks, I'll try to configure sendmail to use Comcast's SMTP server as a smarthost.
-Pete
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Christopher Chan -
John R Pierce -
Peter Loron