Postfix SMTP experiment

Peon

Peon

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Fellas,

I have searched the forums before posting. I do not feel previous posts answered by question regarding reverse DNS lookups on an ADSL line, for SMTP purposes.

Ubuntu, postfix etc,etc. Im fiddling with SpamAssassin, mail storage, user accounting and various tricks and tools, go through the logs and see how it executed. As I can fiddle to much then just restore VMware state. I prefer to have this test server on a local network. I am not keen to hemorrhage money to a upstream provider just for fiddling and testing purposes.

As many of you know, smtp from an adsl line will always be rejected, from "DOMAIN NOT FOUND" to "SENDER REJECTED" to "I DONT FEEL LIKE ROUTING YOUR MESSAGE TODAY". The DSL ip will be rejected and reverse dns will faulter.

How does one overcome this? Im not keen on using ClearOS's dyndns feature supplied by clear solutions. This will work but not the solution if you setup a scratch postfix box.

Peon
 
Overcome this by setting your mailserver's smart host to your ISP's smtp server.
You cannot affect reverse Dns using dyndns or anything like that.
 
What router do you have?
With NetGear's (and im sure some other routers also have this) you can create firewall rules to allow smtp to your server IP.

I think this is what you require?

Regards
 
Like Sinbad said, either forward all internet bound email to a smrthost (your ISP's smtp server) or create another VM and play by sending email between the two VMs. A complete closed environment with two VM's where you also control the DNS is a great way to learn how this all works.
 
By default all good sysadmins block/blacklist mail from dial-up connections as this is the way spammers try to peddle their wares.

You will need to use smarthost in order to smtp mail.



I have set this up using clearOS and iBurst, and it works really well - client is able to SMTP to world+dog via iBurst's SMTP server.
 
Thank you all for the input.

I was hoping to avoid the smarthost plan, wondering if there was a slick DNS workaround.
 
Peon said:
Thank you all for the input.

I was hoping to avoid the smarthost plan, wondering if there was a slick DNS workaround.
Click to expand...

Reverse DNS authority is delegated by IP block. You won't manage to get a dynamic ip address delegated to a DNS outside of your ISP's.
Smart host should work perfectly, and transparently to your users.
 
I keep getting hit by this:

to=<[email protected]>, relay=smtp.isadsl.co.za[196.23.28.232]:25, delay=27, delays=0.01/0.01/24/2.4, dsn=4.0.0, status=deferred (host smtp.isadsl.co.za[196.23.28.232] said: 451-host lookup did not complete 451 Could not complete sender verify (in reply to RCPT TO command))

Im sure this is a DNS issue, dont know where....
 
The_Librarian said:
Smarthosts.
Click to expand...

Not working.

EDIT: changed the login script for auth on smarthost. Works. One should rather use the TAB button to space than just hitting the space bar. I knew this, thought it wouldnt matter though.
 
Last edited:
Smarthost probably with authentication is your best bet.

Sent from South Africas most popular smartphone BlackBerry
 
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