Well, if you’re determined to have IPMI, you’re asking for a lot of extra
expense with minimal benefit.
OTOH, if you power it via PoE or a controllable outlet accessible via your OOB
network, I find that a NanoPi R6S or R.Pi with a USB hub and a bunch of FTDI
serial dongles works great.
I highly recommend the following udev rule, however, to avoid unpleasant naming
surprises on the USB ports:
SUBSYSTEM=="tty", ATTRS{idVendor}=="0403",
ATTRS{idProduct}=="6001",SYMLINK+="tty.FTDI.%E{ID_SERIAL_SHORT}"
This creates an additional /dev/ symlink named tty.FTDI.<Serial>, so for
example:
root@asilomar:/var/log# ls -al /dev/tty* | grep 188,
crw-rw---- 1 root dialout 188, 0 Dec 22 04:06 /dev/ttyUSB0
crw-rw---- 1 root dialout 188, 1 Dec 22 04:06 /dev/ttyUSB1
crw-rw---- 1 root dialout 188, 2 Dec 22 04:06 /dev/ttyUSB2
crw-rw---- 1 root dialout 188, 3 Dec 22 04:06 /dev/ttyUSB3
crw-rw---- 1 root dialout 188, 4 Dec 22 04:06 /dev/ttyUSB4
crw-rw---- 1 root dialout 188, 5 Dec 22 04:06 /dev/ttyUSB5
root@asilomar:/var/log# ls -al /dev/tty.FTDI*
lrwxrwxrwx 1 root root 7 Dec 22 04:06 /dev/tty.FTDI.A99AGU55 -> ttyUSB5
lrwxrwxrwx 1 root root 7 Dec 22 04:06 /dev/tty.FTDI.A9BPURYS -> ttyUSB3
lrwxrwxrwx 1 root root 7 Dec 22 04:06 /dev/tty.FTDI.A9MIOH4N -> ttyUSB4
lrwxrwxrwx 1 root root 7 Dec 22 04:06 /dev/tty.FTDI.A9ZFAU3B -> ttyUSB0
lrwxrwxrwx 1 root root 7 Dec 22 04:06 /dev/tty.FTDI.AQ00OLSN -> ttyUSB1
ttyUSB2 is a non-FTDI adapter that doesn’t report a serial number and will be
replaced next time I’m in the cold.
If you use the FTDI symlinks in your conserver configuration, they don’t change
across reboots, whereas the TTYUSB5 may suddenly be a completely different
device next time you console to it.
If you want most of the advantages of IPMI for a fraction of the cost (rather
than just remote power cycling), then a BLIKVM unit is an excellent
alternative. (It can even provide power cycling for any standard-ish PC Mobo).
Owen
> On Dec 17, 2025, at 16:51, Dan Mahoney via NANOG <[email protected]>
> wrote:
>
> Hey there folks.
>
> Dayjob has historically used USB TTY pods attached to real BSD machines to
> talk to our cisco consoles, with the amazing benefit that with a program like
> Vixie's rtty (or conserver) you can also capture the output of those consoles
> in real-time, and perhaps use that data to identify a connected device.
>
> As a bonus, because the rackmount devices have real DE-9's on them, it means
> they work with any kind of cable you get (not just your standard rj45 cisco
> rollover like you might get with a Cyclades thing -- and you don't have to
> come up with the weird-ass mappings for rj45-serial like you might need like
> our ME4012 NAS (the serial cable is a stereo plug), our smart power strips
> (it's either a stereo plug, or an rj12), or something like an older brocade
> switch (it's a DE9, but it's friggin ODD, and I think it may also be the
> wrong gender).
>
> It also means, since you're running a real OS, you have patches as long as
> the OS is supported (so you're not stuck with "gee it only speaks rsa1024"),
> versus some EOL appliance. But it's also 2u, and since we're recently buying
> a lot of Dell hardware, that's Super Overkill for a dell, so I'm evaluating
> maybe just going "Appliance".
>
> If we stick with an existing unix box for this, I'd want something with
> proper IPMI/OOB (so Rpi is out) but maybe the dumbest, shallowest-depth
> atom64 supermicro you can find, in the event you need to do a reinstall or
> catch a hung system.
>
> Are there things that other folks are using that are "easy" to work with that
> you've found to have Long firmware lives, decent warranties and low hassle?
> Does anything these days actually have DE9s on it?
>
> -Dan
>
> (You may have also seen my note earlier about the Cisco ASR920, which has
> RS232 pins in a USB-A header. No, not via a PL2032 chip inside the host that
> provides a virtual serial...direct txd/rxd/gnd/cts etc, on the USB pins.
> I've seen things you people would't believe)
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