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I am in the process of reinstalling the OS on a machine that will be used to host a couple of applications for our business. The applications will be local only; access from external clients will be via VPN only.

The prior setup used a hosting control panel (Plesk) for most of the admin, and I was looking at using another similar piece of software for the reinstall - but I figured I should finally learn how it all works. I can do most of the things the software would do for me, but I am unclear on the symbiosis of it all. This is all an attempt to further distance myself from the land of Configuration Programmer/Programmer, if at all possible.

I can't find a full walkthrough anywhere for what I'm looking for, so I thought I'd put up this question, and if people can help me on the way I will edit this with the answers, and document my progress/pitfalls. Hopefully someday this will help someone down the line.

The details:

  • CentOS 5.5 x86_64
  • httpd: Apache/2.2.3
  • MySQL: 5.0.77 (to be upgraded)
  • PHP: 5.1 (to be upgraded)

The requirements:

  • SECURITY!!
    • Secure file transfer
    • Secure client access (SSL Certs and CA)
    • Secure data storage
    • Secure connection to another local machine (MySQL)
  • Virtualhosts/multiple subdomains
  • Local email would be nice, but not critical

The Steps:

  • Download the latest CentOS DVD-iso (torrent worked great for me).

  • Install CentOS:
    While going through the install, I checked the Server Components option thinking I was going to be using another Plesk-like admin. In hindsight, considering I've decided to try to go my own way, this probably wasn't the best idea.

  • Basic config:
    Setup users, networking/IP address, etc. Yum update/upgrade.

  • Upgrade PHP/MySQL:
    To upgrade PHP and MySQL to the latest versions, I had to look to another repo outside CentOS. IUS looks great and I'm happy I found it!
  • Add IUS repository to our package manager

    cd /tmp
    wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/x86_64/epel-release-1-1.ius.el5.noarch.rpm
    rpm -Uvh epel-release-1-1.ius.el5.noarch.rpm
    wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/x86_64/ius-release-1-4.ius.el5.noarch.rpm
    rpm -Uvh ius-release-1-4.ius.el5.noarch.rpm
    yum list | grep -w \.ius\. # list all the packages in the IUS repository; use this to find PHP/MySQL version and libraries you want to install
    

    Remove old version of PHP and install newer version from IUS

    rpm -qa | grep php # to list all of the installed php packages we want to remove
    yum shell  # open an interactive yum shell
    remove php-common php-mysql php-cli #remove installed PHP components
    install php53 php53-mysql php53-cli php53-common #add packages you want
    transaction solve #important!! checks for dependencies
    transaction run #important!! does the actual installation of packages.
    [control+d] #exit yum shell
    php -v
    PHP 5.3.2 (cli) (built: Apr  6 2010 18:13:45)
    

    Upgrade MySQL from IUS repository

    /etc/init.d/mysqld stop
    rpm -qa | grep mysql # to see installed mysql packages
    yum shell
    remove mysql mysql-server #remove installed MySQL components
    install mysql51 mysql51-server mysql51-devel
    transaction solve #important!! checks for dependencies
    transaction run #important!! does the actual installation of packages.
    [control+d] #exit yum shell
    service mysqld start
    
    mysql -v
    Server version: 5.1.42-ius Distributed by The IUS Community Project
    

    Upgrade instructions courtesy of IUS wiki: http://wiki.iuscommunity.org/Doc/ClientUsageGuide.


  • Install rssh (restricted shell) to provide scp and sftp access, without allowing ssh login
  • cd /tmp
    wget http://dag.wieers.com/rpm/packages/rssh/rssh-2.3.2-1.2.el5.rf.x86_64.rpm
    rpm -ivh rssh-2.3.2-1.2.el5.rf.x86_64.rpm
    useradd -m -d /home/dev -s /usr/bin/rssh dev
    passwd dev
    

    Edit /etc/rssh.conf to grant access to SFTP to rssh users.

    vi /etc/rssh.conf
    

    Uncomment or add:

    allowscp
    allowsftp
    

    This allows me to connect to the machine via SFTP protocol in Transmit (my FTP program of choice; I'm sure it's similar with other FTP applications).

    rssh instructions appropriated (with appreciation!) from http://www.cyberciti.biz/tips/linux-unix-restrict-shell-access-with-rssh.html.


  • Set up virtual interfaces
  • ifconfig eth1:1 192.168.1.3 up #start up the virtual interface
    cd /etc/sysconfig/network-scripts/
    cp ifcfg-eth1 ifcfg-eth1:1 #copy default script and match name to our virtual interface
    vi ifcfg-eth1:1 #modify eth1:1 script
    

    #ifcfg-eth1:1 | modify so it looks like this:
    DEVICE=eth1:1
    IPADDR=192.168.1.3
    NETMASK=255.255.255.0
    NETWORK=192.168.1.0
    ONBOOT=yes
    NAME=eth1:1

    Add more Virtual interfaces as needed by repeating. Because of the ONBOOT=yes line in the ifcfg-eth1:1 file, this interface will be brought up when the system boots, or the network starts/restarts.

    service network restart
    

    Shutting down interface eth0: [ OK ]
    Shutting down interface eth1: [ OK ]
    Shutting down loopback interface: [ OK ]
    Bringing up loopback interface: [ OK ]
    Bringing up interface eth0: [ OK ]
    Bringing up interface eth1: [ OK ]

    ping 192.168.1.3
    

    64 bytes from 192.168.1.3: icmp_seq=1 ttl=64 time=0.105 ms


  • Virtualhosts
  • In the rssh section above I added a user to use for SFTP. In this users' home directory, I created a folder called 'https'. This is where the documents for this site will live, so I need to add a virtualhost that will point to it. I will use the above virtual interface for this site (herein called dev.site.local).

    vi /etc/http/conf/httpd.conf
    

    Add the following to the end of httpd.conf:

    <VirtualHost 192.168.1.3:80>  
        ServerAdmin dev@site.local  
        DocumentRoot /home/dev/https  
        ServerName dev.site.local  
        ErrorLog /home/dev/logs/error_log  
        TransferLog /home/dev/logs/access_log  
    </VirtualHost>  
    

    I put a dummy index.html file in the https directory just to check everything out. I tried browsing to it, and was met with permission denied errors. The logs only gave an obscure reference to what was going on:

    [Mon May 17 14:57:11 2010] [error] [client 192.168.1.100] (13)Permission denied: access to /index.html denied

    I tried chmod 777 et. al., but to no avail. Turns out, I needed to chmod+x the https directory and its' parent directories.

    chmod +x /home
    chmod +x /home/dev
    chmod +x /home/dev/https
    

    This solved that problem.


  • DNS
  • I'm handling DNS via our local Windows Server 2003 box. However, the CentOS documentation for BIND can be found here: http://www.centos.org/docs/5/html/Deployment_Guide-en-US/ch-bind.html


  • SSL
  • To get SSL working, I changed the following in httpd.conf:

    NameVirtualHost 192.168.1.3:443 #make sure this line is in httpd.conf 
    
    <VirtualHost 192.168.1.3:443>  #change port to 443
        ServerAdmin dev@site.local  
        DocumentRoot /home/dev/https  
        ServerName dev.site.local  
        ErrorLog /home/dev/logs/error_log  
        TransferLog /home/dev/logs/access_log  
    </VirtualHost>  
    

    Unfortunately, I keep getting (Error code: ssl_error_rx_record_too_long) errors when trying to access a page with SSL. As JamesHannah gracefully pointed out below, I had not set up the locations of the certs in httpd.conf, and thusly was getting the page thrown at the broswer as the cert making the browser balk.

    So first, I needed to set up a CA and make certificate files. I found a great (if old) walkthrough on the process here: http://www.debian-administration.org/articles/284.

    Here are the relevant steps I took from that article:

    mkdir /home/CA
    cd /home/CA/
    mkdir newcerts private
    echo '01' > serial
    touch index.txt #this and the above command are for the database that will keep track of certs  
    

    Create an openssl.cnf file in the /home/CA/ dir and edit it per the walkthrough linked above. (For reference, my finished openssl.cnf file looked like this: http://pastebin.com/raw.php?i=hnZDij4T)

    openssl req -new -x509 -extensions v3_ca -keyout private/cakey.pem -out cacert.pem -days 3650 -config ./openssl.cnf #this creates the cacert.pem which gets distributed and imported to the browser(s)
    

    Modified openssl.cnf again per walkthrough instructions.

    #generates certificate request, and key.pem which I renamed dev.key.pem.
    openssl req -sha1 -new -nodes -out dev.req.pem -config ./openssl.cnf 
    

    Modified openssl.cnf again per walkthrough instructions.

    #create and sign certificate.
    openssl ca -out dev.cert.pem -md sha1 -config ./openssl.cnf -infiles dev.req.pem 
    

    IMPORTANT!

    Move the files and reference them from httpd.conf in the new location

    cp dev.cert.pem /home/dev/certs/cert.pem
    cp dev.key.pem /home/certs/key.pem
    

    I updated httpd.conf to reflect the certs and turn SSLEngine on:

    NameVirtualHost 192.168.1.3:443 
    
    <VirtualHost 192.168.1.3:443>
        ServerAdmin dev@site.local  
        DocumentRoot /home/dev/https  
        SSLEngine on
        SSLCertificateFile /home/dev/certs/cert.pem
        SSLCertificateKeyFile /home/dev/certs/key.pem
        ServerName dev.site.local
        ErrorLog /home/dev/logs/error_log
        TransferLog /home/dev/logs/access_log
    </VirtualHost>  
    

    Put the CA cert.pem in a web-accessible place, and downloaded/imported it into my browser. Now I can visit https://dev.site.local with no errors or warnings.


    And this is where I'm at. I will keep editing this as I make progress. Any tips on how to configure SSL email, and/or configuring secure connection to another Box that will be the MySQL server would be appreciated.

    share|improve this question
        
    I don't understand why do you need the virtual network interfaces? –  Milan Babuškov May 18 '10 at 18:13
        
    @Milan because I will have multiple domains/subdomains on this machine. In order to use VirtualHost and SSL Each domain/subdomain will need to have its' own IP address. httpd.apache.org/docs/2.0/ssl/ssl_faq.html#vhosts –  stormdrain May 18 '10 at 20:00
        
    Looks like a waste of IP addresses to me, but ok. Alternatively, you could use different TCP/IP ports for each domain - all on single IP. That way the web server is less dependent on system configuration. –  Milan Babuškov May 19 '10 at 10:03
    1  
    @Milan:Since the setup is local only, I have the luxury of way more available IP addresses than I'll ever need. Setting up additional interfaces, I've found, is a rather quick and painless process comparatively. If I were setting up this system for public use, thanks to Apache2.2.x and TLS upgrades, VirtualHost seems to work better with SSL: serverfault.com/questions/109766/… –  stormdrain May 19 '10 at 13:46
    1  
    Would highly recommend koltsoff.com/pub/securing-centos - a very educational walkthrough on securing CentOS (most of which is easily applicable to other distros) - it doesn't cover the hosting, but everything in there should be understood and applied to any CentOS server that isn't behind a firewall you understand and control. –  dunxd Feb 5 '12 at 18:37

    3 Answers 3

    This guide has a lot of answers about using SSL with Apache, tells you how to create a self-signed certificate, how to get a proper certificate from a recognized certificate authority (CA) and how to create your own, untrusted CA to create a full certificate. http://httpd.apache.org/docs/2.0/ssl/ssl_faq.html

    As for virtual hosts and SSL, each host will need its own IP address or a dirtier solution is to host them on different ports, than the standard :443 due to the nature of SSL certificates, name-based virtual hosting does not get along with SSL; which is why you need another method to differentiate; differing ports/IPs.

    Setting up SSH is pretty easy, it should be running on your server, already. You will want to do a number of things to lock it down.

    PermitRootLogin no
    AllowGroups admins
    PubkeyAuthentication yes
    PermitEmptyPasswords no
    PasswordAuthentication no
    

    It can be added to your /etc/ssh/sshd_config to restrict remote root access, and remove password authentication, instead using public/private keypairs to log in.

    To create your SSH keypair, you can use puttygen in Windows; http://putty.very.rulez.org/download.html or you can create the keypair in a Linux environment like so: ssh-keygen -b 2048 -t RSA -f my_keypair. This will create a my_keypair file and a my_keypair.pub file (only named for this example, I might suggest naming for your username or leaving off -f, and letting it generate ~/.ssh/id_rsa).

    Securely transfer my_keypair to your workstation, for future SSH access, this is the private key, you should not share it with anyone. Then, on the server, create $HOME/.ssh if it does not already exist, mkdir ~/.ssh, then copy the public key (my_keypair.pub) to ~/.ssh/, if you already have authorized_keys in ~/.ssh because you've done this for other things, you can do cat my_keypair.pub >> authorized_keys to append your public key, or cp my_keypair.pub authorized_keys if it doesn't exist.

    Now run chmod 700 ~/.ssh and chmod 644 ~/.ssh/my_keypair.pub ~/.ssh/authorized_keys to set permissions. You can keep a copy of my_keypair in ~/.ssh/ for use when connecting to other hosts, but you should do chmod 600 ~/.ssh/my_keypair to make sure no one else can access it.

    You will want to add a normal user account for yourself, and add yourself to a group other than users, like admins in my example.

    You will probably also want to add your user or group to /etc/sudoers to enable sudo usage, if you haven't already. This is accomplished with the command visudo which is the only way you should edit this file. visudo runs error and syntax checking on your configuration before writing it out, preventing loss of sudo usage.

    username ALL=(ALL) ALL
    

    added to /etc/sudoers will allow username to run sudo yum install blah and will prompt you for your own password. This is handy in the event you have other administrators or temporary administrators, you don't need to share the root password.

    share|improve this answer
        
    If you create a keypair in windows from puttygen, be aware you have to change the format of the public key once you upload it to the server. I don't remember how but youtube it there's actually a video. –  ESW Jun 24 '10 at 9:15

    The problem with your SSL config is that you've not actually enabled SSL, you'd need the Apache directives for that:

    SSLEngine on
    SSLCertificateFile /path/to/cert.pem
    SSLCertificateKeyFile /path/to/key.pem
    

    Without this you'll get those record too long errors, it's because instead of the SSL headers your browser was expecting, it's getting instead just the unencrypted web page in a big chunk.

    share|improve this answer
    1  
    (without this, all you've created is a regular non-SSL vhost listening on port 443) –  JamesHannah May 17 '10 at 22:35

    MySQL from the original package supports SSL. To check your MySQL build, run

    mysqladmin variables | grep ssl
    

    You should find something like have_ssl yes. Set up options ssl-ca, ssl-key and ssl-cert.

    Create user accounts with SSL requirements:

    create user@host identified by 'password'
    grant privilegelist on database.tables to user@host require ssl
    
    share|improve this answer
        
    Thanks for the response. I forgot to mention, though, that I will also be storing files on the db server so it looks like stunnel will work better in this case. –  stormdrain May 20 '10 at 2:25

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