When writing networking software, is there a default, typical, or otherwise de facto standard for MTU size, of which I should be aware? If so, what is it?
Is an MTU size of 1500 (as suggested here: What is the Maximum MTU supported in DSL Standards) a good rule of thumb?
Also, am I over thinking this problem? Is this one of those things people think is important when writing networking software, but in practical, real-world terms, doesn't wind up mattering much since TCP will take care of the details for you?
I ask here, rather than on StackOverflow, because I want the sysadmin point of view when it comes to actual support issues related to MTU size.
UPDATE: based on some of the feedback, and initial answers, I'm narrowing the focus a bit:
- The application I'm writing will communicate between desktops/servers over a WAN connection
- It's typical desktop/server (i.e. not mobile) software, and while it's possible that a tethered laptop will use this software over a mobile network, I'm not concerned with that
- It won't even attempt to deal with any layer of the TCP stack, other than the application layer, for optimization
- VPN overhead can be ruled out for the scope of this question