This is all very curious.
Having followed your advice and run vasm and disabled ifplugd at all levels, I have run the boot sequence several times and observed the screen messages together with the little green light on my 3Com adapter, which tells me when it's active.
The adapter comes on at the same time as the following appears on the screen:
Entering runlevel 2
rc.M - Going multiuser
Now I had already acted on this post upthread, and amended my rc.M file
I had the same problem of not being able to start the network at boot up and having to use VASM to get it started. After much research and experimentation I also reached the stage of successfully starting the network by manually running "/etc/rc.d/rc.inet1 start". This implied that there was nothing wrong with the rc.inet1 script but rather it wasn't being called. What I eventually found was that in my /etc/rc.d/rc.M file a large chunk of code which starts the network was commented out! I don't know how or why this was so, but when I uncommented it the network started on the next reboot. This makes sense as inspection of the code shows that /etc/rc.d/rc.inet is called for each network interface. Hope this helps.
A short while later in the boot sequence the 3Com's light goes out again, around the time the following is being echoed to the screen:
That's puzzling to me, that the adapter seems to be disabled when the system is supposed to be initialising the network.
So I arrive at the command prompt and log in. I wondered for a while whether the adapter would just then come on by itself, as I have always seemed eventually
to find it on. Is it coming on spontaneously, or in response to something I do?
I have tried various things after each boot sequence. I thought I had found it when I tried logging on as root with 'su root' and typing 'ifplugd'. The adapter's light flashed with a beep from the system each time and it then came on constantly, and I was able to execute the '/etc/rc.d/rc.inet1 start' command! Ahh! I thought... I've found what I have to do... but no, the next time I tried booting and doing the same thing, nothing happened! The next time I booted, logged on as usual, and then typed 'startx' to start the windows manager, and the adapter came on then!
So, in summary, I can see from the echo to screen from rc.M that the command '/etc/rc.d/rc.inet1 start' is being executed by the script, but it's not getting inet1 up, as the adapter isn't on. It's not clear why this is occasionally coming on when it does, and not coming on when it doesn't!
Curiouser & curiouser...!