I have been googling awhile. I've tried a few different packages on my windows and linux sides. I think I'm just not understanding something.

I got a serial > ethernet cable at my server and it's plugged into the switch. What do I need on the remote end to hit it? I'm thinking some type of client but nothing I try seems to be able to see anything on the lan. Had the idea that I could get a client on my desktops end and it would be able to find a serial port over the lan. So far not working that way.

You could use minicom to connect and manage your switch. Somehow I think you have got wrong idea what this port is for ... ?

I'm with Emerson.

I assume you have a Cisco managed switch. The serial port on the switch is an ethernet port instead of DB 9 or maybe 25 pin connector that you would of found on PCs or serial MODEMs. It is the console port used to configure the switch. As posted you can use any terminal program like minicom or PuTTy.

It's an rs232 port on the back of my server. I was hoping to get a remote terminal for if it fails to boot so I don't need to haul a monitor out to where it is.

Ouch. Ethernet and serial are nothing alike, not compatible with each other at all. What cable it is you have got there? Generally you connect serial port to another serial port.

If what fails to boot? The server or switch?

There are special devices that are remote ethernet to keyboard, video mouse but they are expensive. Dell and HPs have special boards that basically do the same thing called Irac or ilo.

You can configure the servers serial port as a remote console but you are already using it to control the switch? You would need another computer to be the terminal device.

I have an APC UPS cable, one end is ethernet and the other is USB, it does not mean it is ethernet to USB adapter cable, APC simply used such physical port and made such a cable. Your cable may be similar special cable.

Back in the old days we used special RJ-45 to 9 pin adapters to connect VAX computers and I have a few micro computers I use for routers with a RJ-45 serial port.

Ok thanks. It appears I misunderstood how this all worked. I'm not sure if it's me or it's just very vague. Either way thank you for explaining that.

Maybe a little of both. Back in the days of main frames and traditional minicomputers the system was controlled by a special terminal called the system console. Basically a root terminal that was always logged in. In those days serial terminals would be used to access and program the computer and typically the console terminal was kept locked up in the same room as the computer to limit access.

Now days when booting linux on PCs the first virtual terminal defaults to the system console and it is where you see the boot and kernel messages. It is possible to use a serial port as the system console but it isn't active until the kernel boots and you do not see the BIOS messages.

Many "old school" devices like Cisco managed switches have a serial port system console. You login and type in commands just like you would using the terminal. Cisco has its own unique language used to communicate with its switches.

I don't know why some manufactures use a RJ-45 as a serial port connector. With a switch it is easier since all connectors are the same except for power.

You didn't misunderstand this part.

Many servers today still have a serial port for this specific reason. You may have to activate the "serial console" option in the BIOS Setup, but then you'll be able to remotely manage the server over a serial connection. If you want to reach that serial port over a network, you'll either need a device called a serial port redirector/server, or connect the port on the server to the serial port of another computer using a null-modem serial cable.

As mentioned by others, the cable you've got is not a "serial to ethernet" cable, it's a DE-9 to 8P8C modular plug serial cable. It's used for managing equipment that for some reason use an 8P8C connector for the serial port, typically routers and switches. There are two pinout standards for 8P8C serial connections (because why wouldn't there be?), one being the mirror image of the other, and today the proprietary "Cisco" variant is by far the one most commonly used.

Nothing vague; you have a serial port...you need a serial device to talk to it. And Ethernet is NOT serial.

You need something like this:
https://www.amazon.com/Serial-Ethern.../dp/B00FJEHNSO

...and there are probably cheaper ones as well. You can then telnet/ssh into that IP address, and it will do the 'translation' between serial and network. Your other alternative is to carry a laptop/computer to the switch, and plug it into a serial port on that computer, and run a terminal session through hypercom/minicom/whatever-com.