External Users perspective monitor

I assume you mean you want to measure the performance of externally facing web servers and not monitor the access. Monitoring the access would be a matter of going over the log files on the web servers.

To get an external perspective of your web servers you can do the following:

1. Get a VM hosted in some place far away from your web servers. In my case I choose 3 different geographic locations that are in different portions of the country but correspond to the locations of some of our large customers.
2. Install a Linux variant on the VM(s) and add the nagios monitoring package.
3. Build an APM template and add a "Linux/Unix Script Monitor" component.
4. Get the perl script off your Orion server stored in C:\Program Files (x86)\SolarWinds\Orion\APM\SampleScriptMonitors\LinuxScripts\ScriptProcessorForNagios(tm).pl
5. Use this script as the "Script Body" for the APM component.
6. Use a "Command Line" in the APM component something like this : ${SCRIPT} /usr/lib64/nagios/plugins/check_http  -4 -H www.google.com
7. Substitute in your webserver name in place of www.google.com

Cavets:

1. You need to pay for the hosted VM. I pay $20/month for each VM.
2. You need to be comfortable with Linux.
3. You may need to tweak the ScriptProcessorForNagios(tm).pl script. Sometimes the correct statistical number you want is not in the right place of the nagios return string.

Chris.

I need to monitor access to my servers published on the internet but the SolarWinds server is inside my local network. How can I do this?

Another option is to use Cisco IPSLA.  If you have any Cisco routers that are capable of running Cisco IPSLA that are not located at your datacenter you can have them do HTTP monitoring of your web servers.  You can then either use the Orion IPSLA module to monitor that, or use Orion NPM and build a bunch of UnDP's to monitor it.

I can't think of a distro that has nagios already installed.

If you use a fedora / centos / redhat distro, you can just do a "yum install nagios" and get it installed after the fact.