Unable to send emails using remote SMTP server.

J

Jackster

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Jul 15, 2011
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I have my own dedicated email server that I wish to use rather than DA's as we have everything behind Cloudflare.

But when I try to send emails via Wordpress (I have tried multiple SMTP plugins) I am unable to connect to my SMTP server.
My cPanel server works fine though.

I have used Netcar on my DA box and have confirmed that port 465 is open on the mail server.
Is there a setting in DA that is causing this issue?

Thanks
Jack
 
that is weird, that is an standard open port on DA.
check your firewall or firewall rules
Are your credentials right ?
 
you can't hide smtp from cloudflare,
About Email, Cloudflare Proxy accept only Inbound Email and filter spam for you but don't proxy your smtp

or try route your smtp port to cloudflare accept port
support.cloudflare.com

Identifying network ports compatible with Cloudflare's proxy

Learn which network ports Cloudflare proxies by default and how to enable Cloudflare's proxy for additional ports. OverviewBy default, Cloudflare proxies traffic destined for the HTTP/HTTPS ports l...
support.cloudflare.com support.cloudflare.com

like open 2053 to 587
this will can use both port, and just route from 2053 to 587
 
jamgames2 said:
you can't hide smtp from cloudflare,
About Email, Cloudflare Proxy accept only Inbound Email and filter spam for you but don't proxy your smtp

or try route your smtp port to cloudflare accept port
support.cloudflare.com

Identifying network ports compatible with Cloudflare's proxy

Learn which network ports Cloudflare proxies by default and how to enable Cloudflare's proxy for additional ports. OverviewBy default, Cloudflare proxies traffic destined for the HTTP/HTTPS ports l...
support.cloudflare.com support.cloudflare.com

like open 2053 to 587
this will can use both port, and just route from 2053 to 587
Click to expand...

Not trying to route email via Cloudflare.
We route HTTPS traffic via Cloudflare as standard.
SMTP traffic should go from DA box to mail server box directly. As it does normally in any other standard setup.
 
Jackster said:
Not trying to route email via Cloudflare.
We route HTTPS traffic via Cloudflare as standard.
SMTP traffic should go from DA box to mail server box directly. As it does normally in any other standard setup.
Click to expand...
Then use 3rd party server to try telnet or ping to that port

or try not using plugins and use phpmailer directly to find problem.
 
Same result with AWS SES as with my own mail server.

jamgames2 said:
Then use 3rd party server to try telnet or ping to that port

or try not using plugins and use phpmailer directly to find problem.
Click to expand...
I have tried Telnet, connects fine.
 
Last edited:
event other server can't send too,

you should see log from Email server -< this first it drop packet when try to use send but can telnet normally

and log from sending client



out of idea
you can create ticket to let support check directly
 
Just set up a Wordpress VM on the same host that the DA VM is on and it works fine.
Going to set up another DA VM and see if that does anything.

I am on trial atm so I don't get support tickets.
 
Got it working. Was looking in the wrong place ealier for the Firewall.

1602274977420.png

Under Firewall Configuration there is a whole section about "SMTP Settings".

"SMTP_BLOCK" was On but turning it off did not do anything.
"SMTP_PORTS" was blocking the standard SMTP ports, removing them did nothing.
"SMTP_ALLOWUSER" also did nothing when adding my user.

1602275100033.png

What did work was adding the IP of my mail server to this section.

This is not ideal as trying to use AWS SES servers, of which have like 2 dozen IPs for each zone, is going to be an issue.

Still investigating the issue. Really SMTP_BLOCK and SMTP_ALLOWUSER should just work and would resolve this issue instantly.
I get why this is set up like this, but at the same time, meh?

[edit]

SMTP_BLOCK = on
SMTP_ALLOWUSER = username

This works.

SMTP_BLOCK = off
Does not work.

giphy.gif
 
Last edited:
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Jackster said:
What did work was adding the IP of my mail server to this section.

This is not ideal as trying to use AWS SES servers, of which have like 2 dozen IPs for each zone, is going to be an issue.
Click to expand...
The ports you're trying to use, have you confirmed that they are open outgoing (TCP_OUT) on the one box and in addition to incoming on the mailserver?

The whitelisting via allow would have allowed the server to bypass closed ports, so I suspect this could be the issue. If you grep the server's IP in the mailserver's /var/log/messages, do you see any TCP_IN Blocked messages from prior to the whitelisting?
 
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