Serial over ethernet to program a remote Aduino?

There are commercial products that load a driver on your PC to give a virtual serial port. Data sent to that port gets piped over ethernet to a translator box with a serial output. In theory the Arduino IDE should be able to use the remote serial port as if it were local. Is this likely to work in practice?

mikb55:
There are commercial products that load a driver on your PC to give a virtual serial port. Data sent to that port gets piped over ethernet to a translator box with a serial output. In theory the Arduino IDE should be able to use the remote serial port as if it were local. Is this likely to work in practice?

does it have DTR for auto reset?

does it have DTR for auto reset?

It's possible. Some "serial servers" have assorted modem control settings, and one that asserts DTR when the connection becomes active (just like on a local serial port, allowing the original auto-reset to operate.)
There's also a telnet option to support twiddling the rs232 signals. I think that's less common, though.
We'd have to know the details of exactly what "translator box" and "PC-side driver" you're using, though.

People have written separate "over the air" upload programs for Arduinos with ESP8266s attached to the serial ports, I think. The Uno WiFi 2 is supposed to support this. (it doesn't necessarily have the "serial emulation" in the middle.)

As @westfw wrote, it is possible.
Years ago I worked with DECservers or MOXA Ethernet/RS232 transceivers (RS232 to TTL is needed due to different voltage levels!!!). Both are usable but any ethernet/RS232 transceiver should be usable (should have also DTR) and even ethernet/USB transceivers are on the market.

If I were to go shopping for a converter, what specs (apart from DTR support) are needed for something to work reliably with the Arduino bootloader?

Does latency matter? I saw one adaptor quoted at 2ms.

Latency shouldn't matter, because the upload protocol is very lock-step.
Besides, latency would tend to be dominated by the network.

Data transparency is important. Some converters have problems with newlines, nulls and/or 0xFF, especially if they run the "telnet" protocol. Running telnet is necessary if you want DTR manipulation during the connection (as opposed to just at the start.) But I don't think it should be necessary.

It does need to raise/lower DTR depending on connection status, not just provided it as a constantly ON signal...

but first consider software options for remote upload. for what board do you want to solve this?

Juraj:
but first consider software options for remote upload. for what board do you want to solve this?

Mostly the Mega2560 but sometimes the Mega328 as well. I'm ok with co-locating another micro to act a programmer if that is what's needed.

Not what the OP is asking for but I use usb over cat5e cabling to program my arduinos without removing them from where they are installed. .

A USB over Ethernet hub might work for your task. I have the Silex ds400u2 (SX-DS-4000U2) which I have on my workbench connected by Ethernet to my laptop across the room. I have a USB monitor, keyboard, mouse and Arduino all remotely connected to my desktop, which is easier than moving my laptop each time I'm at the workbench.