I was just curious is it common in enterprise environments for Linux administrators to combine their primary email server (Postfix) with their companies web server (Apache)? I'm just more curious than anything and I know this is a relative question with random possible answers but I was just wondering if hardware resources are not an issue, just from a software / configuration stand point, is it likely to just have mail on a separate server and web on another or do must commonly configure and combine those two services to one Linux machine?

We wouldn't here for several reasons:

- There's enough load on the boxes to justify their own hardware (I know you said hardware reasons weren't an issue, but still);
- If the box needs to be taken down because of either one, both are off-line for the duration;
- There are different groups administering mail and web and neither group needs access to the other's servers for security reasons.

Others will have more reasons for doing it this way and I'm sure plenty will have reasons for doing it other ways. Everywhere I've worked the procedure was basically the same - list your requirements, prioritise them and determine what meets your requirements in priority order.