One of our servers is running a website that sends out email addresses with
logins and passwords upon a user's registration. The email is configured with CDO. We seem to be getting blocked by some email services (see below). Is there a way to configure either rDNS, DNS, PTR, or SPF records to avoid getting bounce-backs?
Our company's public IP is x.x.x.195
The IIS server name is Server1a; private domain is private.com
The site it is sending from is public.com; public IP is x.x.x.140
We are getting bouncebacks from ATT, AOL, and other email services. Here is an
example of one:
Message delivery to the host '204.127.217.21' failed while delivering to the
remote domain 'att.net' for the following reason: An SMTP protocol error
occurred.
The SMTP verb which caused the error is 'MAIL'. The response from the remote
server is '450 service permits 2 unverifyable sending IPs - server1a.private.com
is not x.x.x.195
Problem was a greylisting due to higher requirements by Yahoo, AOL, and several other mail systems. The issue was fixed by updating the SPF record and creating a reverse-dns PTR record that would resolve to our server name.
Related
I am using subdomain for sending email. for example test.example.com. I have configured DMARC,SPF,MX record, Reverse DNS. Checked with mxtoolbox.com and seems perfect.Also checked the IP for blacklist and non of them blacklisted My IP but when I send mail it recieves in Spam folder in my Gmail account. My server is hosted with Digital ocean ubuntu server. It will be helpful if some one give their suggestion
How do these online services of spoof email work?
They usually require the from domain really exists. It means there is a smtp server which accepts the connection.
Let's say I send a mail from test#xxx.com. The site will try to connect to the xxx.com smtp server and it will deliver the message.
The questions are:
How it is able to find the xxx.com domain smtp server?
To correctly deliver the message, xxx.com has to be without authentication. However, also with a fake gmail.com domain, the email is correctly sent, even though Gmail requires auth.
I have just installed VestaCP on a fresh CentOS VPS.
I have set up email for one domain. All mail sent to that domain bounces with the error 550 smtp auth requried
I have commented out the following;
deny message = smtp auth requried
from exim.conf
I have turned off anti-spam.
I still get the bounce with this message.
Specifically, if I send an email from a gmail account google responds:
Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the server for the recipient domain foobar.tld by mail.foobar.tld. [x.x.x.x].
The error that the other server returned was:
550 smtp auth requried
Any experience with this? I have seen the problem on a number of threads but have not found a solution.
I partially solved the problem. It only occurred when sending mail to the smtp server from a domain that was hosted on the same server for web but not for email. When I sent email from a domain that had nothing to do with any domains hosted on the same server as the exim instance, then it got through. I still can't send email from the domain that was causing the problem and I would like to, but I can work around it.
So to be clear in case anyone reads this:
domain1 web is hosted on server1
domain1 email is hosted on google's servers
domain2 is hosted on server1 for web and email
exim is running on server1
when I send email from thunderbird via google's server from email#domain1 to and email#domain2 the exim instance asks google's smtp server for authentication even though the mail is being delivered to a mailbox in its list of domains it can deliver to on the same physical server where it is running.
I suspect that it is suspicious of the from address, which it shouldn't be since the mx records indicate that it does not host mail for that domain.
I have configured my DNN mail server to send out mail using our companies Email service provider. I cannot send any emails to external email server.
For ex. My email provider is testx#ttt.com. I can send emails to testy#ttt.com and textz#ttt.com. However i cannot send to testy#gmail.com or testy#hotmail.com
The error i see in the DNN event viewer is as below
System.Net.Mail.SmtpFailedRecipientsException: Unable to send to all recipients.
System.Net.Mail.SmtpFailedRecipientException: Mailbox unavailable.
The server response was: This domain is not hosted here
I have the same email address configured in my outlook and i can send/recieve to any emails like gmail or hotmail. Following are my DNN email settings
It sounds like one or two things might be happening here:
Your SMTP server isn't set up to allow relaying from the IP address of your web server.
You may need to create an SPF (Sender Policy Framework) or TXT record in DNS for your SMTP server's primary domain that allows SMTP traffic from the IP address of the server where your DNN website is hosted. An SPF record may already be in use for your email domain, but generally you'd add something like this to it: v=spf1 a ip4:1.2.3.4 -all, where 1.2.3.4 is the IP address of your web server.
I run a mail server on my web server, it has SMTP authentication enabled and I added my server's IP address to the whitelist, so no password is required to send out emails if they come from within the server. I did this to allow my web applications to use the SMTP service.
My question is can a spammer spoof a packet with my own IP address and bypass the SMTP authentication?
Emails sent from my email server often end up in the recipient's spam folder and I'm trying to figure out why. I send no more than 200 emails per month.
It isn't possible to spoof your address unless the attacker is between you and your server (which is very unlikely - he would have to be an ISP or to be able to overwatch and control your internet traffic). This is because after an attacker sends a connection request to your server, the server sends a packet to you that the attacker needs to have to be able to establish a connection: http://en.wikipedia.org/wiki/TCP_handshake#Connection_establishment
Try to look at the headers of a mail that gets into the spam folder and look for something that says that your servers IP is blacklisted or something like that.