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4

I hate to turn this into a discussion about tools, rather than about the technology involved, but you may want to look into the use of tcpreplay which takes .pcap files and replays them even at the same speed that they originally came in.


4

Damn it. I fixed it like a min after posting this. Solution: echo 1 > /proc/sys/net/ipv4/ip_forward


3

When I format the smtpd_sender_restrictions so it becomes a little more readable: smtpd_sender_restrictions = reject_unknown_sender_domain, reject_unauthenticated_sender_login_mismatch, reject_known_sender_login_mismatch, hash:/var/spool/postfix/plesk/blacklists, ...


3

That remote domain has an MX record pointing to the loopback address 127.0.0.1 which is either a misconfiguration by the owner of that domain or it's by design. We don't know of any really good reasons to do so: Under what circumstances (if any) should an MX record point to localhost? Either way that makes it impossible to deliver email to them. There is ...


3

I'm going to assume that you have looked into running multiple postfix instances? There are variations you could do (this for example), but they'll involve using the different IPs with different domain names (so you can assign SSL certs to them), and either running one instance which submit internally to different ports in amavisd, then re-injects to ...


3

SPF checks occur early on in the conversation so the sender (probably) doesn't get a chance to send the email before the attempt is rejected. So no, they're not recoverable.


2

Note that it's 250 8BITMIME and not 250-8BITMIME (with the dash). Would this be enough for sendmail to consider that the remote source doesn't support 8bitmime? No. This is called continuation and it only signifies that the line is the last line of the SMTP reply. And generally 8BITMIME should be the only thing required to show that the MTA on the ...


2

99% of the time, email is delivered via the MX record mechanism. The MX record designates which server is authoritatively responsible for accepting email for a given domain. But that doesn't mean that this server is also the server where the recipients mailbox is. The MX record only designates which server to deliver the email to, it doesn't designate which ...


2

This statement is not accurate: " Email delivery is done by Sender's Mail Server sending E-Mail directly to Receiptent's Domain Mail-Server" For example, at my firm, when I send an email from my mail client, I might not have an externally-facing SMTP server at my site. Mail might be routed within my company's Exchange infrastructure. Then, it might ...


1

Honest advice, use normal user accounts and let your Linux system authenticate the users. This is easy to manage and very secure. I don't want to say that other systems are insecure but I trust my Linux system when it comes to storing and authenticating passwords. I use these commands to create users manually. This way they can do no harm on my system. ...


1

if you want all the emails being sent via gmail, you have to set relayhost to smtp.gmail.com:587 as you wrote. This is not enough, though. You need to create and edit the file /etc/postfix/sasl_passwd Write a line in it like below: smtp.gmail.com:587 user@example.com:password where: user@example.com is a valid username in your gmail hosted domain ...


1

SSMTP is expected to be TLS from the start. This should work if you set UseTLS to Yes. This port/protocol has been obsoleted now that the STARTTLS option is available. If you want to use STARTTLS try the submission port (587). I have verified that the submission port is open.


1

Most people use MX or A in their SPF record that covers all of your MX Records and A Records v=spf1 mx a -all If you're not sending from your MX records then you can list out the ip4 addresses you send from. The best way to create your SPF Record, if you're not sure is to use an SPF Wizard You'll go through the questionnaire and it will produce the ...


1

If you just have those two IP-addresses sending mail for the mydomain.com domain, your SPF record should look like this: v=spf1 ip4:1.1.1.1 ip4:2.2.2.2 -all Do not use +all in a SPF record, since that allow the whole internet to send mail from your domain. In the final SPF record you should use -all to indicate that ONLY the listed entries are allowed to ...


1

The RFCs generally recommend a limit of 100 recipient addresses per message. The mail server may expand this list if a recipient is a list known to the server. This applies to the envelope recipients, not the recipients listed on the header. For a mailing lists, it is bad practice to list the recipients unless the message is being sent to a single user, ...


1

I think the problem is here #mynetworks = 168.100.189.0/28, 127.0.0.0/8 Try to add and network 192.168.178.0/24 and del # mynetworks = 127.0.0.0/8, 192.168.178.0/24


1

Sendmail had used to be installed as set root uid program. Sendmail-8.12+ is no longer (by default) installed as set root uid program to avoid security risk. Sendmail executed by non root user passes messages to sendmail daemon running with root privileges at 127.0.0.1:25. Sendmail executed by non root user uses /etc/mail/submit.cf instead of /etc/mail/...


1

Quite a good one, it requires fiddling with zimbra and postfix and unfortunately requires some manual configuration. I suppose you can handle the amazon stuff for getting an account. all commands are done on the cli as the zimbra user. So login with ssh and become zimbra user by su - zimbra create an file for authentication to amazon: echo email-smtp.eu-...


1

Inbound options do not apply to PHPMailer. SSL on port 465 (SMTPS) has been deprecated since 1998, though Microsoft didn't seem to notice. Use SMTP+STARTTLS on port 587 instead, which is what PHPMailer does when you use SMTPSecure = 'tls' & Port = 587. Note that PHPMailer does opportunistic TLS, in that if you don't tell it to use TLS and you connect to ...


1

netstat -b -o lists the network connections, process and PID - you should be able to figure out which IIS worker process is doing all the port 25 connections.



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