Install mail server on Ubuntu or Debian Rumi, September 12, 2023 Disclaimer: This howto is tested on Ubuntu 16, 18, 20 and Debian 10, 11 edition. Installing and configuring postfix Step 1 » Assign static IP and hostname and add a host entry for the host name . Assign hostname in /etc/hostname mail.tweenpath.net Add a host entry in /etc/hosts 192.168.1.10 mail.tweenpath.net… Continue Reading
Postfix to allow Mail Relay from a Trusted IP Rumi, May 27, 2023 Make sure smtpd_recipient_restrictions has permit_mynetworks, something like this: smtpd_recipient_restrictions = permit_mynetworks,<more> This is the default, but if you have -o smtpd_recipient_restrictions=something on an smtpd line in master.cf then it will override main.cf setting. A sample configuration that worked for me is as below- smtp inet n – n – -… Continue Reading
Configure Zimbra to use SendGrid as Smarthost Rumi, February 18, 2023September 12, 2023 Switch to user Zimbra su zimbra Add credentials to relay_password file: nano /opt/zimbra/conf/relay_password Add: smtp.sendgrid.net yourSendGridUsername:yourSendGridPassword Apply configuration to Zimbra postmap /opt/zimbra/conf/relay_password postmap -q smtp.sendgrid.net /opt/zimbra/conf/relay_password zmprov ms `zmhostname` zimbraMtaSmtpSaslPasswordMaps lmdb:/opt/zimbra/conf/relay_password zmprov ms `zmhostname` zimbraMtaSmtpSaslAuthEnable yes zmprov ms `zmhostname` zimbraMtaSmtpCnameOverridesServername no zmprov ms `zmhostname` zimbraMtaSmtpTlsSecurityLevel may zmprov ms `zmhostname` zimbraMtaSmtpSaslSecurityOptions… Continue Reading
Postfix SMTP Rotating IP using IPTables Rumi, August 1, 2022 I got 5 Public IPs. i’m Gonna configure them, so Postfix can use multiple interfaces/ips for outgoing smtp connections. First we need creating Interface aliases for those 5 public IPs. In my system, using centos: # cd /etc/sysconfig/network-scripts/ # cp ifcfg-eth0 ifcfg-eth0:1 Edit ifcfg-eth0:1 # vi ifcfg-eth0\:1 DEVICE=eth0 <– default… Continue Reading
Configure DomainKeys- DKIM (OpenDKIM) with Postfix on CentOS 7 Rumi, March 31, 2021March 31, 2021 OpenDKIM is method to digitally sign & verify emails on the mail servers using public & private keys. In other words opendkim implements the DKIM (DomainKeys Identified Mail) standard for signing and verifying email messages on a per-domain basis. DomainKeys are implemented to reduce the chances of outgoing mails to… Continue Reading
Setup mail server on centos 7 using postfix and dovecot Rumi, March 30, 2021 Installing packages Step 1 » Assign hostname for the server using the below command. [root@krizna ~]# hostnamectl set-hostname mail.krizna.com Step 2 » Make a host entry with your IP in /etc/hosts file. 172.27.0.51 mail.krizna.com Step 3 » Now start installing packages. [root@krizna ~]# yum -y install postfix dovecot After package… Continue Reading
Configuring Postfix to block outgoing mail to all but one domain Rumi, September 6, 2019 This is so simple to do, but I have to look it up every time I need it (not something that comes up regularly!); When configuring a development server, you may find you have a need to ensure that emails will not be sent to any domain except those you… Continue Reading
Install and integrate DKIM with OpenDKIM and Postfix on a CentOS 6 Rumi, August 24, 2019February 4, 2024 UPDATE THE SYSTEM Before going any further, make sure you’re in a screen session and your system is fully up-to-date by running: ## screen -U -S opendkim-screen ## yum update ENABLE EPEL REPOSITORY OpenDKIM is available in the EPEL repository, so we need to enable it on the system before… Continue Reading
Increasing Attachment Size in Posfix Rumi, July 19, 2019 Postfix by default restrict attachment size to approx 10MB i.e. 10240000 bytes. You can check it using following command: postconf | grep message_size_limit To change attachment-size to say 50 MB, run a command like: postconf -e message_size_limit=52428800 Note: If you are running a mail-server with SMTP/IMAP access, you need to change… Continue Reading
Postfix start error on CentOS Rumi, March 7, 2018 When I tried to start postfix today, I got the following message: fatal: parameter inet_interfaces: no local interface found for 1.2.3.4 Solution is straightforward: nano /etc/postfix/main.cf comment out “inet_interfaces = all” add “inet_protocol = ipv4” Continue Reading