Interesting IP issue on my IBM i (all interfaces down, even LAN console)

I have a monitoring service that tells me when my web site is up or down.
It's hosted on my i (now to be called AS/400 from now on) 515 running V5R4
at my office.

Tonight I got an email saying it was down. Cool, it works. Not cool, my
site was actually down.

I got on the LAN that the AS/400 is on. Couldn't ping any IP interfaces on
it. Not even the LAN console IP address.

I ended up doing a "manual IPL" and things were fine after that.

But that leads me to ask... if even my LAN console IP was down, how the
heck am I supposed to be able to get onto the machine to see what is going
on? I was quite troubled and now have a bald spot on the side of my head
where I was scratching it. :)

Thanks for any info... after this, I'd actually like to be able to set up
a dedicated PC to be a console, preferably not over IP. If that's
possible, I'm all ears as I have multiple old laptops I could use for
consoles. :)