Upon replacing my linux router/server with a Solaris one I've noticed very poor network performance. The server itself has no issues connecting to the net, but clients using the server as a router are getting a lot of IP fragments as indicated from some packet sniffing I conducted.

Here was my old setup.
<DSL_Modem>-<Linux Router>-<switch>-<wifi>-<macbook>
- this setup works fine, with no fragmentation or performance issues

Setup 1
<DSL_Modem>-<Sol 11 Router>-<switch>-<wifi>-<macbook>
- this setup has major packet fragmentation

Setup 2 (taking wifi out of the flow)
<DSL_Modem>-<Sol 11 Router>-<switch>-<macbook>
- this setup has major packet fragmentation

I played with various MTU settings on the solaris server internal NIC, but it made no difference so I tried a couple of things with the client box.

I determined the max MTU I could send from my macbook as 1464 without getting fragmentation by using:
ping -D -s 1464 <any internet ip>

Once I manually set my MTU down to 1464 on my macbook instead of the default 1500 web pages started loading normally. So here's the problem...why do I have to manually set the MTU on the client macbook when I have my solaris server setup as a router. Is there some network related tuning I can perform on the server that will address these issues?