Changes

==OBJECTIVE & PREPARATION=PART A: Setting up your NIS Server===*Install the NIS server and client onto your VM 2. yum install ypserv ypbind*Add the following line to the bottom of the file /etc/sysconfig/network NISDOMAIN="<learn-id>.org" YPSERV_ARGS="-p 783"*This should be enough to set the domain name, however there is currently a bug in systemd that prevents this from working properly on its own.**You will also need to start and enable the fedora-domainname service.*Edit the file /etc/yp.conf and set up your domain: domain <learn-id>.org server 127.0.0.1*Create the file /var/yp/securenets: host 127.0.0.1 255.255.255.0 192.168.x.0*Enable and start the NIS (ypserv) service. systemctl start ypserv.service systemctl enable ypserv.service*Backup the configuration file for NIS databases cp /var/yp/Makefile /var/yp/Makefile.orig* Verify that your servers (NFS, ypserv) are running correctly with the following command: rpcinfo -p*At this step you should edit your firewalls to allow RPC and NIS traffic through your firewall (Hint: check the output of rpcinfo -p or iptables traffic on the "lo" interface)*The machine will essentially be communicating with its own NIS server when using the Makefile*Now change to directory /var/yp and run this command to build the information databases make*Enable and start the NIS binding (ypbind) service. systemctl start ypbind.service*Use the following command to verify your NIS server is working - you should see your learnid password record. ypcat passwd*Add a new user named nis-user, with password "ops335".*Run 'ypcat passwd' again.*In order for the new user to show up you will need to recreate the map files- change directory to /var/yp and run the "make" command again.

===PART B: Examining a Problem Solved by NIS===*Ensure your VM3 is still mounting your home directory from VM 2 using autofs. If it is not, revisit last weeks {{Admon/important|Prerequistites|This labdepends on changes made in several previous labs.*Many of you had an issue last week when using NFS as you had differing GID & UID's between systems - when attempting to mount the home directory from the VM2 you received various permission issues. In case you did not experience it, we will intentionally create this issue and then correct it with NIS.*Run the following command grep /home /etc/passwd*Look at the existing users on VM You must have successfully completed labs 3 and compare them with the same users on VM 2. Find one whose credentials differ (Specifically, a user name that exists on both machines4a, but has a different UID). If you have no such user4b, create one.*For example on VM 3: [root@vm3 ~]# cat /etc/passwd | grep home nis-user:x:1000:1000::/home/nis-user:/bin/bash paul:x:1001:1001::/home/paul:/bin/bash*And on VM 2: [root@fvm2 ~]# cat /etc/passwd | grep home paul:x:1000:1000:paul:/home/paul:/bin/bash nis-user:x:1001:1001::/home/nis-user:/bin/bash*While the two hosts share the same users, their UID and GID are different. This will cause a problem when mounting the home directory using NFS.*Back on vm3 try to switch to your learnid (or other account where UID/GID differs between systems) su <learnid> cd ~*You should recieve a permission denied error as the UID on the local system differs from the UID of the file owner on the remote server.*Obtain a listing of the directories 5 in /home: [paul@vm3 /]# ls -l /home drwx------. 3 nis-user nis-user 4096 Mar 11 19:13 paul*Notice that one user's home directory shows up as being owned by a different user.*Try order to access the other user's home directory (it should show up as owned by this user): [paul@vm3 /]# cd /home/nis-user*You should now be successful. Obtain a directory listing. Below is some example output: [paul@vm3 /home/nis-user]$ ll drwxr-xr-x. 2 paul paul 4096 Mar 14 09:09 Desktop drwxr-xr-x. 2 paul paul 4096 Feb 17 05:24 Documents drwxr-xr-x. 2 paul paul 4096 Feb 17 05:45 Downloads drwxr-xr-x. 2 paul paul 4096 Jan 4 10:12 Music drwxr-xr-x. 2 paul paul 4096 Jan 4 10:12 Pictures drwxr-xr-x. 2 paul paul 4096 Jan 4 10:12 Public drwxr-xr-x. 2 paul paul 4096 Jan 4 10:12 Templates drwxr-xr-x. 2 paul paul 4096 Jan 4 10:12 Videos*Create an empty file and able to do a listing again [paul@vm3 ~]$ touch empty_from_vm3 [paul@vm3 ~]$ ll -rw-rw-r--. 1 paul paul 0 Mar 18 14:58 empty_from_vm3 drwxr-xr-x. 2 paul paul 4096 Mar 14 09:09 Desktop drwxr-xr-x. 2 paul paul 4096 Feb 17 05:24 Documents drwxr-xr-x. 2 paul paul 4096 Feb 17 05:45 Downloads drwxr-xr-x. 2 paul paul 4096 Jan 4 10:12 Music drwxr-xr-x. 2 paul paul 4096 Jan 4 10:12 Pictures drwxr-xr-x. 2 paul paul 4096 Jan 4 10:12 Public drwxr-xr-xthis lab. 2 paul paul 4096 Jan 4 10:12 Templates drwxr-xr-x. 2 paul paul 4096 Jan 4 10:12 Videos*Now we will fix this problem by making this machine use NIS for user information*Change users back to root}}

===Part C: Client Configuration===*Install ypbind on your vm3.* You may wish to follow the logs on vm3. In addition to your normal log in, ssh from the host to vm3 and get a continuous feed from the logs with: tail -f /var/log/messages*Edit /etc/yp.conf adding the following line: domain <learnid>.org server 192.168.x.3*Add Below is the following line to the bottom of the file /etc/sysconfig/network NISDOMAIN="<learn-id>.org"*Start the ypbind server with the command. systemctl start ypbind.service*Looking at your logs ensure same diagram that ypbind is registered with rpcbind, if it is unable your firewall may need we referred to be adjusted.*Now when you run over the following commandprevious 2 email labs: ypcat passwd*You should be able to see the 'nis-user' entry from the host machine, matching its credentials.*If you added a mismatched user, you must update the map files on the host.*Edit the /etc/nsswitch.conf file (on VM3 only) and change the following lines so they appear as below: passwd: nis files shadow: nis files group: nis files*Save and exit the file.*Ensure ypbind will start at boot and restart the vm.*Log into vm3 using one of the conflicting accounts. You should now be able to see the files in their home directory with the correct mapping.

===Part D[[Image: Obtaining autofs maps through NIS:===*Make sure autofs service is installed on your VM 3 (If you completed the nfs lab, it is)Email-servers. If it is not, go back and complete the NFS lab now.*Copy the autofs files from VM3 to your VM2. scp /etc/auto.{home,master} root@vm2:/etc/png]]

*Edit /etc/autoNote the two globes in the above diagram.master on VM2 and remove Those globes represent the Internet that your emails travel through in order to be received by an e-mail recipient. The 'etc' prefix from auto.home's path: /home auto.home --timeout=60*Regenerate smaller globe (the one your NIS maps and run: ypcat auto.home*You should receive the following: No such map auto.home. Reason: No such map in server's domain*You will need workstation is connected to look into the Makefile ) cannot be trusted to determine how to add autosend mail messages unencrypted'''.home and auto.master to the list of files shared by NIS.*After making changes to your Makefile, regenerate your maps again and run the same command as above. You should now see the file and its contents when you run ypcat auto.home. [root@vm2 yp]# ypcat auto.home The '''larger globe usually involves inter-fstype=nfs4ISP traffic,rwoften through an internet trunk line,nosuidso it is also unencrypted,soft 192.168.70.3:/home/&*On vm3 delete the autofs filesbut it cannot be easily accessed by hackers, and edit the /etc/nsswitch.conf file so that autofs consults NIS. Reboot the machine.*When the VM comes back uppen-testers, log in as any non-privileged user and ensure auto mounting of home occurredor evildoers'''.

===Part E: Adding the other VMThere are '''s===*When two important general truths you have successfully made this change on vm3, repeat these steps so that vm1 will also use NIS for user identification, and mount home directories using autofs files located on vm2.**Warningneed to understand about email encryption''': When configuring the location of the NIS server to bind to, use the ip address instead of the hostname. When the machine is booting, you have no guarantee that named starts before ypbind.

:* '''Email (the way the vast majority of people use it) travels from SMTP server to SMTP server uncencrypted'''. :: That means that nothing sent over email is <u>truly</u> secure. But attempting to continually intercept SMTP server to SMTP server traffic is difficult and expensive, not worth doing for the little bit of money most of us have in our bank account. :* '''Email travelling over a LAN (especially Wifi, but any local network) is always encrypted'''. :: If e-mail traffic on a LAN was not encrypted, it would be easy and inexpensive to intercept (in order to obtain your username and password). These days, unencrypted connections from your client to your SMTP/IMAP/POP3 server very rarely exist. You see in our diagram that one of the SMTP connections is supposed to be encrypted (this is the one that would be "LAN" traffic) and the IMAP connection as well (this one is either LAN-like traffic or is connecting to localhost, which is a different scenario altogether). We're going to secure the two connections that we left to be in plain text previously. Unfortunately encrypting things is rarely a straighforward process. Fortunately we have a whole week to spend on it. ===Online Resources=Completing ==* [https://en.wikipedia.org/wiki/Transport_Layer_Security TSL, SSL Definition]* [https://www.e-rave.nl/create-a-self-signed-ssl-key-for-postfix Create a self signed SSL key for Postfix]* [http://wiki2.dovecot.org/SSL/DovecotConfiguration Dovecot SSL configuration]  == INVESTIGATION 1: GENERATING A SELF-SIGNED CERTIFICATE == According to Wikipedia (https://en.wikipedia.org/wiki/Transport_Layer_Security), '''Transport Layer Security''' (TLS) and its predecessor, '''Secure Sockets Layer''' (SSL), both of which are frequently referred to as 'SSL', are cryptographic protocols designed to provide communications security over a computer network. Normally (in production), you would need to pay a "certificate authority" to issue a '''certificate''' for you. That is essentially '''a "signed" public key''' that will tell strangers on the internet that your server is really yours (i.e. the certificate authority says so). There is an obvious problem with the previous statement but that is mainly how public key encryption works on the Internet today. We will be generating our own public keys, mainly in order to avoid paying for a certificate. We will not have enough time to get into the details of what all the following commands do in this section. They are from [https://www.e-rave.nl/create-a-self-signed-ssl-key-for-postfix this blog post]. If you don't understand what the blog post refers to but would like to understand in more details, a good recommended book for interest, called Crypto by Steven Levy, provides a more in-depth discussion of encryption and security. The public key cryptography concepts in this lab are the same in a previous lab ([http://zenit.senecac.on.ca/wiki/index.php/OPS335_Lab_1#SSH_Keys Lab1: SSH]), although the terminology is slightly different. A simple way to summarize the Labdifferences is::* The '''.key''' file is your private key.:* The '''.crt''' file is your public key.  === Encrypting Postfix with Transport Layer Security (TLS) ===Exploration questions'''Perform the following steps:''' #What Let's start with the "sending" SMTP server we have on VM2. Run the following, replacing <u>andrewsmith.org</u> with '''<u>your</u> domain name''': <source lang="bash">mkdir -p /root/postfix-keys /etc/ssl/{private,certs}cd /root/postfix-keysopenssl genrsa -des3 -out vm2.andrewsmith.org.key 2048chmod 600 vm2.andrewsmith.org.keyopenssl req -new -key vm2.andrewsmith.org.key -out vm2.andrewsmith.org.csropenssl x509 -req -days 365 -in vm2.andrewsmith.org.csr -signkey vm2.andrewsmith.org.key -out vm2.andrewsmith.org.crtopenssl rsa -in vm2.andrewsmith.org.key -out vm2.andrewsmith.org.key.nopassmv vm2.andrewsmith.org.key.nopass vm2.andrewsmith.org.keyopenssl req -new -x509 -extensions v3_ca -keyout cakey.pem -out cacert.pem -days 3650chmod 600 vm2.andrewsmith.org.key cakey.pemcp vm2.andrewsmith.org.key cakey.pem /etc/ssl/privatecp vm2.andrewsmith.org.crt cacert.pem /etc/ssl/certs</source> ::'''NOTE:''' Those commands will create a certificate, a certificate signing request, a certificate authority, and sign your certificate with your certificate authority.<br>This would be the same as in the real world except there you would contact a real CA, here you're making up your own. <ol><li value="2">Now, configure Postfix to use the generated certificate, by adding the following to your '''main.cf''' file:</li></ol> <pre># Settings to enable secure SMTP using my self-signed certificate:smtpd_tls_auth_only = nosmtpd_use_tls = yessmtp_use_tls = yessmtpd_tls_key_file = /etc/ssl/private/vm2.andrewsmith.org.keysmtpd_tls_cert_file = /etc/ssl/certs/vm2.andrewsmith.org.crtsmtpd_tls_CAfile = /etc/ssl/certs/cacert.pemtls_random_source = dev:/dev/urandomsmtpd_tls_loglevel = 1</pre> === Setting Up and Testing Encryption with Thunderbird === '''Perform the following steps:''' #Currently your Thunderbird is set up to use '''vm2.yoursenecaid.org''' for an SMTP server, with <u>no</u> security. Change that to use '''STARTTLS''' instead (you can change it under '''account settings --> Outgoing Server''').# We haven't set up any user authentication, just an encrypted channel;therefore, leave the '''authentication method''' at the value: '''none'''.#When you try to send an email Thunderbird will warn you about the purpose self-signed certificate. You obviously know it's your certificate so you can tell Thunderbird to trust it:  [[Image:SMTP-certificate-warning.png]]  ::'''NOTE:''' Your message may look slightly different (This author, that created the diagram above, made a little mistake when generating the certificate). <ol><li value="4">After you confirm that security exception, send another email to yourself and make sure you receive it.</li><li> Notice that from the user's point of view nothing is different. But if you were an evildoer trying to steal an identity (the rpcinfo command?difference is huge). Before it was trivial and now it's computationally prohibitive.</li></ol> === Encryption Dovecot with Secure Socket layer (SSL) === Now we will ensure that our '''Dovecot''' connection is secure, and enforce that policy. With SMTP, you will need to allow plain text connections since that is the only method to pass email from server-to-server. With IMAP, there is no server-to-server interaction, but rather only client-to-server interaction. The reason to have an unencrypted IMAP connection would be if your '''IMAP server''' and '''IMAP client''' were the <u>same</u> machine. '''Perform the following steps:''' #Explain Let's start by generating a new certificate for Dovecot on your vm3 machine by issuing the purpose following commands:<source lang="bash">mkdir /etc/ssl/{private,certs}openssl genrsa -des3 -out vm3.andrewsmith.org.key 2048chmod 600 vm3.andrewsmith.org.keyopenssl req -new -key vm3.andrewsmith.org.key -out vm3.andrewsmith.org.csropenssl x509 -req -days 365 -in vm3.andrewsmith.org.csr -signkey vm3.andrewsmith.org.key -out vm3.andrewsmith.org.crtopenssl rsa -in vm3.andrewsmith.org.key -out vm3.andrewsmith.org.key.nopassmv vm3.andrewsmith.org.key.nopass vm3.andrewsmith.org.keyopenssl req -new -x509 -extensions v3_ca -keyout cakey.pem -out cacert.pem -days 3650chmod 600 vm3.andrewsmith.org.key cakey.pemcp vm3.andrewsmith.org.key cakey.pem /etc/ssl/privatecp vm3.andrewsmith.org.crt cacert.pem /etc/ssl/certs</source> ::'''NOTE:''' This process is identical to what you've done for the vm2 certificate. In fact if your IMAP and SMTP servers are on the same machine you can share the certificate between them. In our case, they are not on the same machine. <ol><li value="2">Next, we need to configure Dovecot to use this for encrypted connections and not allow any kind of plain text connections. Edit the '''10-auth.conf''', <u>and</u> '''10-ssl.conf''' files and change the following settings (note: these parameters already exist in those files, just find them and set them to the correct value):</li></ol> <source lang="bash">ssl = requiredssl_cert = <path_to_your_crt_filessl_key = <path_to_your_key_filedisable_plaintext_auth = yes</source>  <ol><li value="3">Now, we will disable normal imap connections, leaving only imaps (secured imap) allowed. Edit the make '''10-master.conf''' file and set the port number in '''inet_listener imap''' to '''0'''.</li><li>Your key/certificate doesn't have a '''.pem''' extension but they are PEM-encoded files. You can confirm that using the '''file''' command. If you're interested, learning more about configuring Dovecot for SSL, refer to the following documentation: [http://wiki2.dovecot.org/SSL/DovecotConfiguration Dovecot SSL configuration].</li></ol> === Verifying that Mail Messages are Encrypted=== '''Perform the following steps:''' #Use the '''ss''' command to confirm you're only listening on the '''imaps''' port, and not the plain imap port.#Next, reconfigure your account settings in Thunderbird to use the '''SSL/TLS''' connection security with your IMAP server, leaving the password as '''Normal Password'''. ::'''NOTE:''' When you send your test email, you will get another warning because you're using a self-signed certificate on '''vm3'''. Make certain to authorize the exception. '''Record steps, commands, and your observations on this investigation in your OPS335 lab log-book''' == INVESTIGATION 2: INSTALL, CONFIGURE &amp; RUN WEBMAIL APPLICATION (Roundcube Mail) =={|cellpadding="15" width="40%" align="right" |- what does it valign="top" |width="10%" | [[Image:Roundcube.png|thumb|right|200px|'''Roundcube''' webmail application Logo<br>GPL,<br> https://commons.wikimedia.org/w/index.php?curid=1772791]] |width="10%" |[[Image:roundcube-pic.png|thumb|right|300px|Screencapture of '''roundcube''' webmail application running in order to send and receive mail messages via a web-browser.]]  |} In the investigation, we will simply install, configure and run the '''roundcube''' webmail application. '''Perform the following steps on vm1:''' *Perform a search on the roundcube application in order to access the website.*Either Download the "zipped tarball" from their website from a direct link or use the wget command to download directly from a download link (This part may take some effort depending on the Sourceforge website).*Extract the "zipped tarball" and rename the generated directory that contains download source code to: '''webmail'''.::* Use the '''--no-same-owner''' option when extracting the tar achive to ensure that the files do?not keep the original owner (who will not exist on your system).#Explain *Change the purpose ownership of the '''temp''' and '''logs''' directories so they belong to apache.*This service needs to be able to write to several directories ('''temp''' and '''logs''') that SELinux prevents write access to. If you are in a section that has SELinux set to '''enforcing''', run the following commands to let it know that apache should be allowed to write to files in those directories.<source lang="bash">semanage fcontext -a -t httpd_log_t '/var/ypwww/securenets html/webmail/temp(/.*)?'semanage fcontext -a -t httpd_log_t '/var/www/html/webmail/logs(/.*)?'restorecon -v -R /var/www/html/webmail</source>::*If your machine does not have the semage command, use yum to install the policycoreutils-python package.*In the directory now named "webmail", there will be a filenamed '''INSTALL''' which will walk you through the rest of the Roundcube installation.<br /><br />Some installation tips to consider: ::* Be careful about copying &amp; pasting the MySQL setup part: take time and pay attention to detail: do not try to "rush it".::* You will need to install additional Apache modules including: '''php-xml''' and '''php-mbstring'''.::* Don't forget to set the password in the roundcube configuration. *Note that both of your IMAP and SMTP servers are on different machines (i.e. not on vm1). Therefore, you will need to set the following options for Roundcube: ::* '''$config['smtp_server']'''::* '''$config['default_host']'''::* '''$config['default_port']''' :::'''NOTE:''' The last <u>two</u> entries above refer to your IMAP server *You should be able to test the configuration in your Roundcube installer after completing Step 3.</li><li>Try to test if the roundcube webmail application is working by sending and receiving e-mail messages.* {{Admon/important |Backup your VMs!|You MUST perform a '''full backup''' of ALL of your VMs whenever you complete your '''OPS335 labs''' or when working on your '''OPS335 assignments'''. You should be using the dump command, and you should use the Bash shell script that you were adviced to create in order to backup all of your VMs.}} '''Record steps, commands, and your observations on this investigation in your OPS335 lab log-book''' ==COMPLETING THE LAB==In completing this lab you have gained experience... '''Depending on your professor you will either be asked to submit the lab in class, or online. Follow the appropriate set of instructions below.''' ===Online Submission (Peter Callaghan's Classes only)===Follow the instructions for lab 8 on moodle. ===In Class Submission==='''Arrange evidence (command output) for each of these items on your screen, then ask your instructor to review them and sign off on the lab's completion:''' ::<span style="color:green;font-size:1.5em;">&#What is x2713;</span>Thunderbird with a message sent and received using encrypted channels.::<span style="color:green;font-size:1.5em;">&#x2713;</span>New Thunderbird server configuration for your account.::<span style="color:green;font-size:1.5em;">&#x2713;</span>Logs on vm2 and vm3 showing the message has been sent and received.::<span style="color:green;font-size:1.5em;">&#x2713;</span>Your webmail showing your inbox::<span style="color:green;font-size:1.5em;">&#x2713;</span>Your webmail sending an email out::<span style="color:green;font-size:1.5em;">&#x2713;</span>You receiving that mail on an exernal account::<span style="color:green;font-size:1.5em;">&#x2713;</span>Download the labcheck8.bash checking bash shell script by issuing the command:<br><br>'''wget http://matrix.senecac.on.ca/~peter.callaghan/files/OPS335/labcheck8.bash'''<br><br>set execute permission and run the shell script on your '''c7host''' machine. ::*For '''Peter's classes''', follow his Online Submission instructions in Moodle.::*For '''Murray's classes''', run command (piping to the '''more''' command) and show output to instructor.::<span style="color:green;font-size:1.5em;">&#x2713;</span>Completed Lab8 log-book notes.  ==EXPLORATION QUESTIONS== #Briefly define the term '''TSL'''.#Briefly define the term '''SSL'''.#List the steps to setup Encryption for Postfix with TLS.#List the steps to setup Encryption for Dovecot with SSL.#List the steps to setup Encryption for the function Thunderbird application.#Provide a brief description of the portmapper servicefollowing terms as they relate to mail servers:#*'''Open Relay'''#*'''SPF'''#*'''DKIM'''# How does a webmail application differ from using another MUA like Thunderbird?#What ports did you need List the additional Apache modules that are required in order to open on your firewallrun the Roundcube web application?