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Hello for whoever read this,

My new post will be in blog.mochtar.net , see you in my new blog site.

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Using HAPROXY Against Zimbra MTA Services, reveal origin IP

We often use HAProxy when deploying zimbra in large environment for load balancing traffic espesially in MTA services  port 25, 465 and 587. but using default configuration  in haproxy and zimbra  affecting sender IP will be read as HAProxy server’s IP, so we cannot trace email by it’s origin IP. this is a big issue when dealing with spammer either from outside or internal.

Luckily there are option in postfix for read original IP from traffic that was sent by haproxy. the configuration are postscreen_upstream_proxy_protocol (if using postscreen as it’s a default in smtp port 25 since zimbra 8.7) and smtpd_upstream_proxy_protocol then from haproxy side by adding send-proxy option.

So here’s the steps for configuring it:

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[ClearOS_6] Make ldap service listen to all IP

In ClearOS We can set Ldap service listen to all interface by setting Publish Policy option to All Networks, but maybe for security concern the service was not for ldap but ldaps (SSL ldap protocol) which listen in port 636.

Because there is an application that will be using ClearOS ldap as authentication backend cannot using ldaps (as it’s been hardcoded from  vendor) so we need to force ldap (port 389) service to listen in all IP.

So here’s the steps.

  • Edit init service for slapd
vi /etc/init.d/slapd
  • Go to line number 72 then add following lines.
for ip in $AUTOMAGIC_LANIPS; do
      harg="$harg ldap://$ip"
done
  • Save and exit, then restart slapd service to apply the changes
service slapd restart
  • Make sure the modified file will not replaced if there is update for package openldap-servers (do as your own risk)
vi /etc/yum.conf
  • Under section [main] add following line
exclude=openldap-servers
  • make sure ldap service port are listening to all available IP.
netstat -tnap | grep LISTEN | grep 389

 

[ZIMBRA] Prevent User Customizing “FROM” header

Background

Some of our Zimbra customers are complaining for authenticated user can customizing FROM header which can lead to fraud email. this issue can be reproduce by using thunderbird once compose an email as following picture.

customize_from_header.png

or by using this script, change variables username, password, fake_from and to_addr based on your environment.

Solution

I created customized milter engine using python milter library for my workaroud with following features:

Continue reading “[ZIMBRA] Prevent User Customizing “FROM” header”