I wanna build a serial console server. So i can access a Debian Server in my network if i locked myself out of SSH.
I was thinking for something like that:
ttyd/picocom -------> screen /dev/ttyUSB0
+---------------+-------+ +-------+-----------+
|GL-AR300M16 |CP2102 | |CP2102 |Debian |
|OpenWRT 22.03.3|ttyUSB0+----------+ttyUSB0|11 Bullseye|
+------+-+------+-------+ +-------+----+-+----+
|WAN | |LAN | +--------+ |LAN | |LAN |
|eth0.1| |eth0.0+--------+ SWITCH +--------+eth0| |ethX|
+------+ +------+ +---+----+ +----+ +----+
|
+---+-----+
|Client |
|SSH/22 |
|HTTPS/443|
+---------+
So if the LAN Connection to the Debian Server fails, i still could get onto the console and fix /etc/network/interfaces to reach it again.
I have a bunch of WR703n/WR710n, but they are all restricted to 4MB Flash, or already used and modded too much and are EOL.
Question #1: Which device is at the moment the WR703n from 8 Years ago?
- cheap
- at least one 100Mbit Port
- VLAN capable NIC is a plus
- i do not care for WiFi
- at least 1x USB 2.0
- UART is a plus (soldering is OK)
- µUSB is OK, Power through USB-C is a plus
- 16MB Flash
Which device would you pick? GL-AR300M16 for example, any better?
Question #2: Which device would you pick for the USB-UART-USB NullModem Cable?
There is a USB-FTDI-USB Cable on the market, which is quite pricey.
I like the USB CP2102 devices. Atm they are at 5-8€ per item.
Any better?
OpenWRT and Debian Driver Support should be easily possible.
Question #3: On the Debian Host, i thought putting screen /dev/ttyUSB0 into the root crontab with @reboot should be sufficient.
Question #4: On the OpenWRT Host, i thought picocom(minicom?) Should be sufficient for the beginning or rare use.
ttyd would be nice. I guess for ttyd it's some effort to push it into a working https/443 setup without any mixed content warnings on the client.
Any thoughts about that one?