Multiple SMTP Relay for single domain

[Umar Draz]

Hi

I want to use multiple SMTP relays for my domain @example.com through
sender_dependent_relayhost

Here is my sender_dependent_relayhost_maps

@example.com smtp.post1.com
@example.com smtp.post2.com
@example.com smtp.post3.com

when I restart my postfix I got error

postmap: warning: relayhost_map.db: duplicate entry: "@example.com".

Would you please anybody help how i can use multiple smtp relays for single
domain or single email?

Br.

Umar



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[Viktor Dukhovni]

Post by Umar Draz
sender_dependent_relayhost

You probably don't really want to do this (or more precisely you
think you want this, but lack the right information to conclude
that this is a mistake and there is a much better solution).

Post by Umar Draz
Here is my sender_dependent_relayhost_maps
@example.com smtp.post1.com
@example.com smtp.post2.com
@example.com smtp.post3.com

This is not how Postfix maps work, but almost certainly we need
not bother to correct this, since what you're trying is likely
not the right approach in the first place.

What is your actual goal? Are you operating a border MX host?
An internal mailhub? A submission server? A mailbox hosting
SMTP server? Or some combination of the above?

Which email messages are you trying to deliver? where are you trying
to deliver them? Why?

My guess is you have a border server, and you want to send to multiple
internal relays, in that case, you need a transport table:

main.cf:
indexed = ${default_database_type}:${config_directory}/
transport_maps = ${indexed}transport

transport:
example.com relay:[relay.example.com]

DNS:
relay.example.com. IN A 192.0.2.1
relay.example.com. IN A 192.0.2.2
relay.example.com. IN A 192.0.2.3

If you can't add A records to the zone file for example.com, you
can always add these to the "localhost." zone on the MTA.

transport:
example.com relay:[relay.example.com.localhost.]

DNS:
relay.example.com.localhost. IN A 192.0.2.1
relay.example.com.localhost. IN A 192.0.2.2
relay.example.com.localhost. IN A 192.0.2.3

with the localhost zone served by the caching resolver on the MTA.

[Umar Draz]

Hi Victor,

Thanks for your reply,

I want this

http://www.cyberciti.biz/faq/postfix-multiple-isp-accounts-smarthost-smtp-client/

I have 4 different username and passwords for remove smtp servers.

Br.

Umar



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[Viktor Dukhovni]

Post by Umar Draz
Thanks for your reply,
I want this
http://www.cyberciti.biz/faq/postfix-multiple-isp-accounts-smarthost-smtp-client/

That's more of a solution, not a problem description.

Post by Umar Draz
I have 4 different username and passwords for remote smtp servers.

For what purpose? To use all 4 in parallel, regardless of sender
address? Or to direct mail from specific sender addresses via the
corresponding ISP? Or else explain in more detail.

[Umar Draz]

Hi Victor,

We have created a Frontend software for sending emails, we want to send
emails in bulk.

From that frontend software we will just pass

from address : e.g ***@example.com
and smtp server which is defenitly our server
and to address (a loop of address around 500,000)

now We want above 500,000 emails should deliver through 4 SMTP relays
through our Postfix email server.

the from address will be ***@example.com

Br.

Umar



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[Viktor Dukhovni]

Post by Umar Draz
We have created a Frontend software for sending emails, we want to send
emails in bulk.
From that frontend software we will just pass
and smtp server: which is definitely our server
and to address: (a loop of address around 500,000)
Now we want above 500,000 emails should deliver through 4 SMTP relays
through our Postfix email server.

Who operates the SMTP relays? From your earlier description these
4 four relays have username + password login access, which sounds
like mail submission services for end-users operated by ISPs, not
bulk mail delivery services for businesses.

It would be unwise to try to deliver 500,000 email messages through
4 user accounts intended for people typing a few email messages a
day sent to one correspondent or a group of friends.

[Umar Draz]

Here is

postmarkapp.com
mandrillapp.com
www.mailjet.com
mailgun.org

Now my question is, is this possible? if yes then how?

Br.

Umar



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[Viktor Dukhovni]

Post by Umar Draz
postmarkapp.com

http://developer.postmarkapp.com/

Things You Should Know

Postmark is for transactional email only. You may not send
newsletters, announcements to your lists or any other bulk email. If
you're uncertain if your email qualifies as 'transactional', you can
always contact support and we'll review your usage.

Post by Umar Draz
mandrillapp.com
www.mailjet.com
mailgun.org

Similar considerations may apply to the others. If you're sending 500,000
messages at once, that does not sound "transactional" to me.

Post by Umar Draz
Now my question is, is this possible? if yes then how?

You can use a different sender address to direct individual messages
to each of the 4 providers via sender dependent relayhost settings.
No promises this will work for very long, as most likely your mail
is spam.

[Umar Draz]

So

I can not use @example.com for these 4 SMTPs instead I need to do this

***@example.com smtp1.com
***@example.com smtp2.com
***@example.com smtp3.com
***@example.com smtp4.com

?

Br.

Umar



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[Viktor Dukhovni]

Yes. And don't send unsolicited bulk email.

[Umar Draz]

Hi Vicktor,

Thanks for your help.

Br.

Umar



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