I'm writing this one for my own reference because almost everything I do for work, is done through SSH port forwarding. If you're not familiar with SSH port forwarding, you'll have to read up on it elsewhere. And the reason why we use SSH port forwarding is because it is secure and powerful.

I generally set up my port forwards to run on my local computer on an arbitrary port and configure SSH to create a proxy connection to the normal port on a remote computer. Then I configure my application to connect to my local computer on the chosen arbitrary port.

For example, I would create my virtual hosts in /etc/hosts:

sudo nano /etc/hosts

127.0.0.1 local1A.fwd
127.0.0.1 local1B.fwd
127.0.0.1 local1C.fwd

let's say I want to forward my local requests on ports 6800, 6801, 6802 to remote servers on ports 3012, 3013, 3014. Start by modifying your ssh config:

nano .ssh/config

add the following:

host remote1A
hostname 111.111.111.111 #remote IP address goes here
user my_username #server username goes here
localforward local1A.fwd:6800 111.111.111.111:3012

host remote1B
hostname 111.111.111.111 #remote IP address goes here
user my_username #server username goes here
localforward local1B.fwd:6801 111.111.111.111:3013

host remote1C
hostname 111.111.111.111 #remote IP address goes here
user my_username #server username goes here
localforward local1C.fwd:6802 111.111.111.111:3014

You should now be able to ssh to remote machines:

ssh remote1A

and similarly for 1B and 1C.

Now, lets say you want to create another 3 local hosts and simultaneously port forward to another 3 remote machines via exact same port numbers. This is where you'll run into problems, because you can only use one local port at a time on 127.0.0.1. The workaround it is to create secondary addresses to your loopback interface 127.0.0.2, 127.0.0.3 and so on. The command to add the secondary IP address is:

ifconfig lo0 alias 127.0.0.2/32

Now you can add new set of hosts:

127.0.0.2 local2A.fwd
127.0.0.2 local2B.fwd
127.0.0.2 local2C.fwd

And use the same set of port numbers to tunnel through another set of remote servers:

host remote2A
hostname 222.222.222.222 #remote IP address goes here
user my_username #server username goes here
localforward local1A.fwd:6800 222.222.222.222:3012

host remote2B
hostname 222.222.222.222 #remote IP address goes here
user my_username #server username goes here
localforward local1B.fwd:6801 222.222.222.222:3013

host remote2C
hostname 222.222.222.222 #remote IP address goes here
user my_username #server username goes here
localforward local1C.fwd:6802 222.222.222.222:3014

Marko

Following my post on Snow Leopard Gotchas, I discovered another problem you might run into. SL comes with currently the latest version of PHP 5.3.0. However, not all PHP projects will play nice on v5.3.0. What you could do is:

1. build and configure an older version of PHP from source - e.g. 5.2.11
2. Install Entropy PHP (note: this will modify your SL Apache config files).
3. Or just be lazy and install MAMP (Macintosh, Apache, MySQL, PHP) in a few seconds.

I chose the last option for 5 reasons:
1. I'm lazy
2. Comes with PHP 4.4.9 & 5.2.10
3. It installs a complete package in one directory
4. It doesn't mess with my existing apache config files
5. it's easy to uninstall.

This is particularly useful for content editors who have phobia of terminal windows (I don't blame them). Hopefully some developers will find this useful too.

After you've downloaded and installed MAMP, you'll notice that the installer created /Applications/MAMP directory. Launch your MAMP Control Center, start your services and away you go.

By default, your Apache web server will run on port 8888. You can change this to port 80 in Preferences, but if you do that you will have to make sure that your OS X Web Sharing is stopped. You can stop it in System Preferences=>Sharing=>Web Sharing.

Normally your Apache virtual would be here:

/etc/apache2/users/*.conf or /etc/apache2/extra/httpd-vhosts.conf

MAMP keeps virtual hosts separately in:

/Applications/MAMP/Library/vhosts

If you ever want to uninstall MAMP, all you need to do is Trash /Applications/MAMP directory and you're done. It's simple and clean.

For more info see MAMP documentation.

Problems you may have with Entropy PHP

NOTE: always backup any .conf file you are going to modify or remove.

Entropy PHP will add a new config file in /etc/apache2/other and possibly modify your httpd.conf. If you're having problems running PHP, there could be various symptoms. The one I was seeing in apache error logs was this one:

child pid 7563 exit signal Segmentation fault (11)

I'm not sure what this means exactly, but it happens when your Entropy config file:

/etc/apache2/other/+entropy-php.conf

tries to load the problematic php module:

LoadModule php5_module /usr/local/php5/libphp5.so

To solve this, I would recommend removing all Entropy stuff and go back to your native PHP 5.3.0. You could try removing, or backing up +entropy-php.conf and uncomment the following line in your httpd.conf

LoadModule php5_module libexec/apache2/libphp5.so

Also check that this file exists:

/etc/apache2/other/php5.conf

and that it contains

<IfModule php5_module>
AddType application/x-httpd-php .php
AddType application/x-httpd-php-source .phps

DirectoryIndex index.html index.php
</IfModule>

 

I recently upgraded to Snow Leopard from 10.5 and everything went relatively smoothly. I was particularly pleased to see extra 13GB of hard drive space.

However, I noticed a couple of things that I wasn't so pleased about:

1. Apache unable to start
2. PHP disabled
3. MySQL unable to start

I've already walked a couple of people through this, so if you run into the same problem you can try the following:

1. For some reason Snow Leopard modified the following file:

/etc/apache2/extra/httpd-ssl.conf

I was using a self-signed SSL certificate for one of my local sites, which was stored in my custom "SSL" directory. The path to my SSL cert was specified in httpd-ssl.conf, but after upgrading to Snow Leopard, that path was replaced with the default path:

SSLCertificateFile "/private/etc/apache2/server.crt"
SSLCertificateKeyFile "/private/etc/apache2/server.key"

The default .crt and .key files didn't exist on my system, hence Apache failed to start. The error I got was:

Syntax error on line 99 of /private/etc/apache2/extra/httpd-ssl.conf SSLCertificateFile: file '/private/etc/apache2/server.crt' does not exist or is empty

You actually have to type 'httpd' in your terminal window to see those errors.

2. PHP disabled.  This problem is closely related to the previous one and it is very simple to fix.  In your httpd.conf file uncomment the following line:

LoadModule php5_module libexec/apache2/libphp5.so

For some reason Snow Leopard upgrade commented this line out for me.

3. MySQL unable to start.  This one scared me a little bit as I do all of my development work on my local machine running against a local MySQL database.   I typically start my MySQL server in terminal:

sudo mysqld -u root

To my surprise, I go this:

mysqld: command not found

The problem was that the following symbolic link was deleted: {/xtypo_code}/usr/local/mysql{/xtypo_code}
mysql symbolic link points to your current version of MySQL install, typically in the same directory. In my case, that directory is here:

/usr/local/mysql-5.0.45-osx10.4-i686/

All you need to do is recreate the symbolic link and you should be able to start your MySQL server again. You can create the symbolic link in your terminal window by typing the following:

sudo ln -s /usr/local/mysql-5.0.45-osx10.4-i686/ mysql

Note: You need to cd into /usr/local/ before running the command above.