ops535a2

N e t w o r k C o n f i g u r a t i o n P a g e | 1

Andrew Greene #027993047 OPS535

Documentation

Assignment 2

OPS535

By: Andrew Greene

Student # 027993047

Professor: Raymond Chan

Network Mail

Configuration Documentation



Table of Contents

NETWORK TOPOLOGY ........................................................................................................................................... 3

IP ADDRESSING SCHEME ........................................................................................................................................ 3

ADDING MX RECORDS TO DNS .............................................................................................................................. 4

SETTING UP POP3/IMAP SERVER ON VM3 ............................................................................................................. 4

CONFIGURING DOVECOT TO USE POP ................................................................................................................... 4

TESTING / TROUBLE SHOOTING DOVECOT LOCALLY .............................................................................................. 4

TESTING / TROUBLE SHOOTING DOVECOT REMOTELY ........................................................................................... 6

INSTALLING/CONFIGURING SENDMAIL .................................................................................................................. 6

TROUBLESHOOTING SMTP SERVER ........................................................................................................................ 7

SETTING UP USERS MAILBOXES USING NFS VIA VM2 ............................................................................................. 9

ADDING NEW EMAIL USER TO YOUR DOMAIN ...................................................................................................... 9

INSTALLING SQUIRRELMAIL ................................................................................................................................. 10

TESTING SQUIRRELMAIL ...................................................................................................................................... 11

IS THE PROBLEM ON THE SERVER? ....................................................................................................................... 11

IS THE PROBLEM WITH THE NETWORK? .............................................................................................................. 12

IS THE PROBLEM WITH THE LOCAL EMAIL CLIENT? .............................................................................................. 13

RPM PACKAGES REQUIRED .................................................................................................................................. 13

SERVICES REQUIRED FOR THIS EMAIL SYSTEM FUNCTION ................................................................................... 14



Network Topology

IP Addressing Scheme DNS Server

VM1

NFS Server

VM2

NIS & POP3 / IMAP Server

VM3

Network ID: 192.168.8.0

Subnet Range:

192.168.8.1 – 192.168.8.254

Subnet Mask: 255.255.255.0

Network ID: 192.168.8.0

Subnet Range:

192.168.8.1 – 192.168.8.254

Subnet Mask: 255.255.255.0

Network ID: 192.168.8.0

Subnet Range:

192.168.8.1 – 192.168.8.254

Subnet Mask: 255.255.255.0

IP Address: 192.168.8.53 IP Address: 192.168.8.2 IP Address: 192.168.8.3



Adding MX Records to DNS You will need to add MX records to your forward zone file so that mail will be routed to the correct

server when it is received.

Edit /var/named/chroot/var/named/named.my-hosts and the following 2 records:

mail IN CNAME vm3

aplus.ca. IN MX 10 mail.aplus.ca.

Once the following records have been added you will need to restart the named service for the changes

to take effect:

Run the following command to restart DNS:

Service named restart

Setting Up POP3/IMAP Server On VM3

In order to setup a POP3 and IMAP server on vm3 you will need to download and install the dovecot

package using yum. This package contains the imap-login and pop3-login daemons which use the imap

and pop3 protocols. By default dovecot only runs IMAP so you will need to configure dovecot to use

POP.

Configuring Dovecot to use POP

Edit the /etc/dovecot.conf file with the following line:

Protocols = imap imaps pop3 pop3s

After making these changes restart the dovecot service:

/sbin/service dovecot restart

Next you will want to make this service start up by default on the next boot:

Chkconfig dovecot on

Testing / Trouble Shooting Dovecot Locally

First you will want to check that the dovecot service is running:

Service dovecot status



If the service is running you will want to test connectivity locally:

Open a terminal then run the following commands

[root@mail ~]# telnet localhost pop3

+OK dovecot ready.

user vm3mail

+OK

pass password

+OK Logged in.

list

+OK 1 messages:

1 622

.

retr 1

+OK 622 octets

Return-Path: [email protected]

X-Original-To: vm3mail

Delivered-To: [email protected]

Received: from localhost.localdomain (localhost.localdomain [127.0.0.1])

by mail.aplus.ca (Sendmail) with SMTP id 943284B43

for <johndoe>; Thu, 22 Feb 2007 09:06:37 -0500 (EST)

Message-Id: [email protected]

Date: Thu, 3 Apr 2012 09:06:37 -0500 (EST)

From: [email protected]

To: undisclosed-recipients:;

X-IMAPbase: 1172153557 1

Status: O

X-UID: 1

Content-Length: 5

X-Keywords:

test

.

quit

+OK Logging out.

Connection closed by foreign host.

[root@vm3 ~]#

After sending the test email if you do not receive it you should check the /var/log/maillog for errors

pertaining to the email you sent.

mailto:[email protected]

mailto:[email protected]



Testing / Trouble Shooting Dovecot Remotely

Next you will want to run the same command as above but this time from a different server and include

the FQDN with the following command:

[root@mail ~]# telnet mail.aplus.ca pop3

Use the same commands from above to send another test email from the remote server if you run into

problems check that you have DNS functioning properly and that the named service is actually running

on VM1. If it is next you will want to check /var/log/maillog and look for any errors pertaining to the

email you just sent from the remote server.

Installing/Configuring Sendmail

You will need to download the following packages in order to configure send mail properly sendmail and

sendmail-cf:

Yum install sendmail

Yum install sendmail-cf

After you have installed the required packages you will need to find and change the following files

located in the /etc/mail/ directory:

Edit the /etc/mail/sendmail.cf file with the following line

# SMTP daemon options

O DaemonPortOptions=Port=smtp,Name=MTA

# who I masquerade as (null for no masquerading) (see also $=M)

DMaplus.ca

Edit the /etc/mail/sendmail.mc file with the following line

dnl # The following example makes mail from this host and any additional

dnl # specified domains appear to be sent from mydomain.com

dnl #

MASQUERADE_AS(`aplus.ca')dnl



Edit the /etc/mail/local-host-names file with the following line

# local-host-names - include all aliases for your machine here.

mail.aplus.ca

aplus.ca

Edit the /etc/mail/access file with the following line

# by default we allow relaying from localhost...

Connect:localhost.localdomain RELAY

Connect:localhost RELAY

Connect:127.0.0.1 RELAY

After you have configured all of the files previously mentioned you will need to Rebuild the file using

either the Makefile in the configuration directory or by issuing the command

m4 sendmail.mc > /etc/sendmail.cf

then you will need to restart the sendmail service on all of the virtual machines:

Service sendmail restart


Chkconfig sendmail on

Troubleshooting SMTP Server

Step 1. Ensure that your mail client setup is correctly configured. 1. In the configuration section of your mail client, ensure that your outgoing mail server is pointing to the mail server you want to use. 2. Verify that the computer you are trying to send email from is not running a firewall that may be interfering with SMTP traffic on port 25. Ensure that if you are behind a firewall, that it is not blocking the network traffic between your mail client and the mail server. 3. Verify if other similar configured mail clients are able to send out mail. If so, try to find out the differences with yours and if needed correct and retry. 4. If the underlying operating system has a telnet capable client, verify if a connection on port 25 (SMTP) of the mail server.



Open a command line and type telnet mailserver.mydomain.com 25 A sendmail server will answer with a following similar output: 220 mailserver.mydomain.com ESMTP Sendmail 8.13.8+Sun/8.13.8; Mon, 21 Apr 2008 11:36:17 +0200 (CEST) When you type the ?help? command the available commands the mail server understands are listed: 214-2.0.0 This is sendmail version 8.13.8+Sun 214-2.0.0 Topics: 214-2.0.0 HELO EHLO MAIL RCPT DATA 214-2.0.0 RSET NOOP QUIT HELP VRFY 214-2.0.0 EXPN VERB ETRN DSN STARTTLS 214-2.0.0 For more info use “HELP “. 214-2.0.0 To report bugs in the implementation contact Sun Microsystems 214-2.0.0 Technical Support. 214-2.0.0 For local information send email to Postmaster at your site. 214 2.0.0 End of HELP info Try the following to send an e-mail from the command line: helo clienthostname.mydomain.com 250 clienthostname.mydomain.com Hello clienthostname.mydomain.com [129.159.231.54], pleased to meet you mail from:[email protected] 250 2.1.0 [email protected]… Sender ok rcpt to:[email protected] 250 2.1.5 [email protected]… Recipient ok data 354 Enter mail, end with “.” on a line by itself subject: This is a test to:[email protected] This contains the BODY of a test mail . 250 2.0.0 m3L9aH0W018247 Message accepted for delivery quit 221 2.0.0 mailserver.mydomain.com closing connection Note the dot (“.”) at the end of the mail body.



If this test succeeds (mail is delivered to it’s final destination) you most likely have a configuration issue on your mail client. 5. If the underlying operating system allows you to analyze the network traffic on the network interface(s) (using ethereal, wireshark, netcap, tcpdump, snoop, etc…) t ry to capture the network traffic while trying to send a mail form the mail client. Analyze if there is SMTP traffic between your client and the mail server.

Setting Up Users Mailboxes using NFS via VM2

Now that you have your POP3/IMAP server up and running you will need to set up the users mailboxes

to use the NFS share via vm2. The first thing you will need to do is mount the /var/spool/mail directory

to vm2 from the mail server (vm3) but before you can mount this directory you will need to edit the

exports file on vm2 to all vm3 to mount that directory.

Edit /etc/exports add the following line to that file:

/var/spool/mail 192.168.8.3(rw,no_root_squash)

Then run the following command to update your exports information:

Exportfs –a

You should now be allowed to mount that directory from vm3 on vm2

Mounting the vm3 /var/spool/mail directory on vm2 with the following command:

mount -t nfs 192.168.8.2:/var/spool/mail /var/spool/mail

You will also need to edit the /etc/fstab file with the above information if you want the directory to be

mounted automatically next time your system boots up.

Adding new email user to your domain

If you want to add a new email user you will need to run the following command:

Useradd user-name-here

Then you will have to give that user a password with the following command:

Passwd user-name-here



You should note that if your /etc/default/useradd file has not been updated to use the NFS shared

directory you will need to add some options to the useradd command

Useradd -d home_dir

Next you will need to update the NIS maps info to include the new users you have just created.

Running the following command to update NIS:

/var/yp/Makefile

Once the updates have been made you can confirm that the user has been created by running the

following command from vm1 or vm2:

Ypcat passwd

Installing Squirrelmail

You will need to download the squirrelmail package in order to use webmail

Yum install squirrelmail

Then you will need to start the httpd service with the following command:

Service httpd start


Chkconfig httpd on

Then you will need to configure send by running the following command

/usr/share/squirrelmail/config/conf.pl

Type in D and press Enter to select the Set pre-defined settings for specific IMAP servers menu. Type in

dovecot and press Enter.

Then type in 2 and press Enter and select the server settings menu.

After that you type in 1 and press Enter to select the Domain menu. Type in your domain name and

press Enter. Save your changes and quit when you are done.

The final thing to do is set the SELinux rules use the following commands:

setsebool httpd_can_network_connect on

setsebool httpd_can_sendmail on



Testing Squirrelmail

Click the browser icon at the top near the System menu to launch the Firefox web browser.

In the address box, type in http://localhost/webmail/src/configtest.php and press Enter. Check for any

errors.

In the address box, type in http://localhost/webmail and press Enter. Type in a valid username and

password and click Login.

Is the problem on the server?

The best way to test server problems is to try to use your webmail. Webmail is hosted on the server

itself, and so bypasses your network and your local email client. This makes it ideal for troubleshooting.

Visit your webmail URL:

http://vm2.aplus.ca/webmail

Log into webmail with your full email address and email password.

If you CAN'T log in, please try to reset your password.

o If you still get an authentication error, this is most likely a server issue.

o If you don't get an error, but it takes a very long time to log in and/or times out, please

skip to Email troubleshooting - mailbox size.

If you CAN log in, proceed to the next step.

Send yourself a test message. You can send to this same email address, or to an external email address

(such as a Hotmail or Gmail account). Reply to the message to test both sending and receiving.

If you get an immediate error when attempting to send or receive, note the exact error. This is a

server issue.

If you get a bounceback, please skip to Email troubleshooting - bouncebacks.

If you get no error, but the message has not delivered for at least five minutes, please skip to

Email troubleshooting - missing emails.

If you can successfully send and receive from webmail, this indicates that the server is fine.

Proceed to the next step, then the next section, to troubleshoot possible network problems.

There are a small number of server problems that might not be "caught" by the webmail test. If you

notice one of the following, please first continue with the next troubleshooting sections, because these

problems are just as likely to be caused by a network or email client problem. If you finish

troubleshooting and are still having one of the problems described below, continue to the final step.

If you have SMTP or Outgoing mail server connection problems, the mail server may be

configured incorrectly.

If you have problems with POP but not IMAP, webmail uses IMAP only, so again, the mail server

setting in your email client may be configured incorrectly.



Is the problem with the network?

Some email problems can occur between your computer and the (mt) Media Temple server. There are

dozens of connection points between your computer and the server. There's a connection from your

computer to your local network, from your local network to your Internet Service Provider, from your

Internet Service Provider to the next Internet Service Provider down the line, and so on. A problem with

one of these connection points is a network problem. Follow the steps below to continue

troubleshooting:

Run a telnet test to the server for the appropriate port. You can run this test from your command line

telnet aplus.ca 25

You should replace example.com with your own mail server name (the same as your domain name in

most cases), and 25 with the port number you are try to test. Here's a summary of port numbers related

to email:

25 - standard outgoing SMTP port

Note - this port is consistently blocked by Internet Service Providers in an effort to prevent spam. See

the special Outgoing mail blocked on Port 25 section below for further assistance.

587 - alternate outgoing SMTP port

465 - SSL encrypted outgoing SMTP port

110 - incoming POP port

995 - SSL encrypted incoming POP port

143 - incoming IMAP port

993 - SSL encrypted incoming IMAP port

Examine the results of your telnet test. A response of "220" or "Connected" indicates connection

success - continue on to the email client troubleshooting below. A timeout or "Unable to connect"

message indicates that you have a network problem.

While a problem on a specific port may not show itself in a generic traceroute, it doesn't hurt to try. For

detailed instructions, on running a traceroute, see Using the traceroute command. For quick reference,

run one of the following from your command prompt:

traceroute aplus.ca



Is the problem with the local email client?

If your webmail test and your telnet tests from the previous section haven't turned up any server or

network problems, this indicates that the problem is most likely with your local email client. The

suggestions go in order from least to most changes required for your current setup.

The best thing you can do for your email client is to double-check all of your settings. Even if they are

correct, sometimes re-typing them can jog your email program into functioning correctly. We have a list

of articles with the correct settings here: Third-party email applications.

If that doesn't resolve the issue, you may want to try recreating the email account. Again, that can jog

your software into using the correct settings. See the link above for helpful walkthroughs.

Perform an online search for any specific error messages that you see in the email client. You can also

search in that email program's help forums specifically.

Contact the support team for your specific email application. Check their website for instructions on

how to receive support.

Reinstall the email client - note that this will delete any existing downloaded emails and custom settings!

Try a different email client. Thunderbird is free and works on both Mac OS X and Windows.

RPM Packages Required

VM1 DNS Server :

Apache Web Server

BIND

Sendmail

Sednmail-cf

Squirrelmail

VM2 NFS Server:

Apache Web Server

NFS

Sendmail



Sednmail-cf

Squirrelmail

VM 3 NIS and POP3/IMAP Server:

Apache Web Server

BIND

Dovecot

NIS

Sendmail

Sednmail-cf

Squirrelmail

Services Required For This Email System Function Named (vm1,vm3)

Dovecot (vm3)

sendmail (vm1,vm2,vm3)

ypbind(vm1,vm2,vm3)

ypserv(vm3)

yppasswdd(vm3)

ops535a2

Documents

underlying

internet service

network configuration

local email

local network

named service

email client

service start