PostFix forwarder - LDAP lookup

louis-m

I've just had a bash at this with pfsense 2.1_x64 and windows 2008 r2 and it works fine. wouldn't work with some username though eg Administrator etc

Slightly off topic but is there any advantage to using this apart from the mail not hitting the exchange server at all?

marcelloc

@louis-m:

Slightly off topic but is there any advantage to using this apart from the mail not hitting the exchange server at all?

It's reduces exchange server load and external link bandwidth as it rejects the email on header checks.

marcelloc

@DQM:

Same result, marcelloc ! Any advise?

Are you sure your password is correct? Is there special characters on it?

DQM

@marcelloc:

@DQM:

Same result, marcelloc ! Any advise?

Are you sure your password is correct? Is there special characters on it?

Dear marcelloc,

I am sure password is correct. Doest it require Exchange server must be installed already in the Actice Directory org?

Thanks,

marcelloc

@DQM:

I am sure password is correct. Doest it require Exchange server must be installed already in the Actice Directory org?

The script extracts email public information from users at AD. if email address is included by exchange server, then it requires Exchange server.

att,
Marcello Coutinho

voona

Having the same issues binding to LDAP. Any ideas guys? 2008 R2 Domain Controller

Thanks

DQM

@marcelloc:

@DQM:

I am sure password is correct. Doest it require Exchange server must be installed already in the Actice Directory org?

The script extracts email public information from users at AD. if email address is included by exchange server, then it requires Exchange server.

att,
Marcello Coutinho

Hi Marcello,

After installing Exchange server, it is working well now. But another issue is SPF feature does not work.
I have created TXT record for abc.com(PfSense was able to resolve TXT record of abc.com). After that, I telnet to send mail by smtp command (user1@abc.com send to user1@abc.com), and I can push phishing emails to Postfix Forwarder.

Any advise?

Thanks,
DQM

DQM

Dear Marcello,

I'd like to mention the list of task that I did on the Postfix Forwarder on following:

I cannot insert the customise "smtpd_banner" into main.cf. It seens does not allow saving after reboot the Pfsense box. It only allow saving if don't reboot the box. Right?
SPF doesn't work once selected "Strong" at Header verification, only work if select "Basic"
Any changes in the Antispam tab wouldn't send mail to it and got an error message like "501 5.1.7 Bad sender address syntax". After change to "Basic" at Header verification, everything will be ok again.

Could you please help to explain in more details?

Thank you,
DQM

voona

ive tried and tried to get this to ldap scrape from my DC and it doesnt work. I can connect from 50 ldap clients with the same username as password and it works 100%

can anyone share their configs etc - 2008 R2 Domain Controller.

Is the a guide or document to set this up?

Thanks

DQM

@voona:

ive tried and tried to get this to ldap scrape from my DC and it doesnt work. I can connect from 50 ldap clients with the same username as password and it works 100%

can anyone share their configs etc - 2008 R2 Domain Controller.

Is the a guide or document to set this up?

Thanks

Hi voona,

Please follow up the guide below:

Step 1: Install p5-perl-ldap by run command below

i386
pkg_add -r http://e-sac.siteseguro.ws/packages/8/All/p5-perl-ldap-0.4300.tbz

amd64
pkg_add -r http://e-sac.siteseguro.ws/packages/amd64/8/All/p5-perl-ldap-0.4300.tbz

Step 2: Modify adexport.pl file at /usr/local/etc/postfix/adexport.pl

Change the first line of this file to #!/usr/local/bin/perl5.12.4 -w

Step 3: Run command below for testing result
/usr/local/bin/php -q /usr/local/www/postfix_recipients.php

If you get number of recipient from LDAP, then it is working well

P/S: Make sure that Exchange server or any Mail server which is able to public email address attribute of users to LDAP server was installed on your system.

GL,
DQM

voona

Ok LDAP is working now i had a space in the username and it didn't like it.

Still seem to be errors when installing the mailscanner package.. clamav doesnt install properly can someone point me in the right direction

Cheers

RobinGill

@louis-m:

Slightly off topic but is there any advantage to using this apart from the mail not hitting the exchange server at all?

@marcelloc:

It's reduces exchange server load and external link bandwidth as it rejects the email on header checks.

In addition this feature is very valuable as it prevents backscatter.

Backscatter is when a spammer sends emails to an invalid address at your domain with a spoofed sender address. The intended result of this is to spam the intended recipient i.e the spoofed sender with NDR's from your mail server.

If postfix is configured without this check, it will relay every email it receives that passes other enabled checks to your mail server. When your mail server realises it does not know of a valid recipient/mailbox to deliver the mail to, it should send an NDR to the spoofed sender.

NDR's can be disabled, but this is against RFC2821.

marcelloc

@DQM:

I'd like to mention the list of task that I did on the Postfix Forwarder on following:

I cannot insert the customise "smtpd_banner" into main.cf. It seens does not allow saving after reboot the Pfsense box. It only allow saving if don't reboot the box. Right?

Did you tried to include this option on postfix custom options field on gui?

@DQM:

SPF doesn't work once selected "Strong" at Header verification, only work if select "Basic"

Any changes in the Antispam tab wouldn't send mail to it and got an error message like "501 5.1.7 Bad sender address syntax". After change to "Basic" at Header verification, everything will be ok again.

I have strong header set and it looks like spf is working, do you have any error message or log you detected it.
If it's a bug during package save settings, I can fix next week.

DQM

@marcelloc:

@DQM:

I'd like to mention the list of task that I did on the Postfix Forwarder on following:

I cannot insert the customise "smtpd_banner" into main.cf. It seens does not allow saving after reboot the Pfsense box. It only allow saving if don't reboot the box. Right?

Did you tried to include this option on postfix custom options field on gui?

@DQM:

SPF doesn't work once selected "Strong" at Header verification, only work if select "Basic"

Any changes in the Antispam tab wouldn't send mail to it and got an error message like "501 5.1.7 Bad sender address syntax". After change to "Basic" at Header verification, everything will be ok again.

I have strong header set and it looks like spf is working, do you have any error message or log you detected it.
If it's a bug during package save settings, I can fix next week.

Dear Marcello,

I have tried to insert the customise "smtpd_banner" by GUI and it is well now. But SPF and any change in the Antispam tab still did not work when "Strong" was selected (I perform testing by SMTP command - telnet to send mail, I did not test by other SMTP server). Does has problem with sending email by command?

Thanks,
DQM

marcelloc

check config files with basic and strong header check enabled to see if spf options are included or not.

DQM

Dear Marcello,

Now I have one more problem. It is RBL feature on the PF, it does not work. Below is content of my config file:

/usr/local/etc/postfix/main.cf
#main.cf
#Part of the Postfix package for pfSense
#Copyright (C) 2010 Erik Fonnesbeck
#Copyright (C) 2011 Marcello Coutinho
#All rights reserved.
#DO NOT EDIT THIS FILE

mynetworks = /usr/local/etc/postfix/mynetwork_table
mynetworks_style = host
smtpd_banner = mail-gw-01.abc.com ESMTP
relay_domains = abc.com
transport_maps = hash:/usr/local/etc/postfix/transport
local_recipient_maps =
mydestination =
mynetworks_style = host
message_size_limit = 10240000
default_process_limit = 100
#Just reject after helo,sender,client,recipient tests
smtpd_delay_reject = yes

Don't talk to mail systems that don't know their own hostname.

smtpd_helo_required = yes
smtpd_helo_restrictions =

smtpd_sender_restrictions = reject_unknown_sender_domain,
permit

Allow connections from specified local clients and rbl check everybody else if rbl check are set.

smtpd_client_restrictions = permit_mynetworks,
reject_unauth_destination,
check_sender_access hash:/usr/local/etc/postfix/sender_access,
check_client_access pcre:/usr/local/etc/postfix/cal_pcre,
check_client_access cidr:/usr/local/etc/postfix/cal_cidr
permit

Whitelisting: local clients may specify any destination domain.

#,
smtpd_recipient_restrictions = permit_mynetworks,
reject_unauth_destination,
check_sender_access hash:/usr/local/etc/postfix/sender_access,
check_client_access pcre:/usr/local/etc/postfix/cal_pcre,
check_client_access cidr:/usr/local/etc/postfix/cal_cidr,
reject_spf_invalid_sender,
permit

soft_bounce = yes
postscreen_greet_wait = ${stress?2}${stress:6}s
postscreen_greet_action = enforce
postscreen_access_list = permit_mynetworks,
cidr:/usr/local/etc/postfix/cal_cidr
postscreen_dnsbl_action= enforce
postscreen_blacklist_action= enforce
postscreen_dnsbl_sites=zen.spamhaus.org, bl.spamcop.net
postscreen_dnsbl_threshold=2

Does my config file has any issues? Could you please help to solve it?

Thank you for your support,
DQM

marcelloc

Are you sure it's not working?

the setup is fine and rbl lists are applied on postscreen daemon

postscreen_greet_wait = ${stress?2}${stress:6}s
postscreen_greet_action = enforce
postscreen_access_list = permit_mynetworks,
         cidr:/usr/local/etc/postfix/cal_cidr
postscreen_dnsbl_action= enforce
postscreen_blacklist_action= enforce
postscreen_dnsbl_sites=zen.spamhaus.org, bl.spamcop.net
postscreen_dnsbl_threshold=2

This last arg says that a hostname must be on both lists to get blocked

DQM

Are you sure it's not working?

I'm sure. Because I have tested by telnet from an IP address which is listed on zen.spamhaus.org (I have checked with another SMTP server) but RBL feature on the PF didn't action. So, I am able to push a lot of messages to it.

This last arg says that a hostname must be on both lists to get blocked

This means the IP address which perform sending email must be listed on both zen.spamhaus.org and bl.spamcop.net then RBL feature would action? Right?
Could you please help to explain in details?

Thanks,
DQM

marcelloc

@DQM:

This means the IP address which perform sending email must be listed on both zen.spamhaus.org and bl.spamcop.net then RBL feature would action? Right?
Could you please help to explain in details?

change RBL threshold to 1 on antispam tab, apply config and test again

DQM

Hi Marcello,

I have checked log of PF and I would like to show you as below:

relay=192.168.1.100[192.168.1.100]:25, delay=36, delays=31/0/0/5, dsn=5.7.1, status=bounced (host 192.168.1.100[192.168.1.100] said: 550 5.7.1 IP address 115.73.183.198 has been blocked by the RBL provider zen.spamhaus.org due to rule (Spamhaus). Please check http://www.spamhaus.org/query/bl?ip=115.73.183.198 for further detail. (in reply to end of DATA command))

Highlighted is message that is generated by my Exchange server (not PF) after PF forward the message to it.

Based on the log above, seems the RBL on my PF is working. Correct? But I have a question that why does not PF perform an action (drop, rejetc) spams and generate a message same as my Exchange server? Could you please help on this?

Thanks for your help,
DQM