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How does one telnet into Open Firmware?

YesWeCat

YesWeCat

macrumors newbie
Original poster
May 11, 2020
29
24
Europe
I have seen many small tutorials (https://flylib.com/books/en/3.126.1.41/1/) explaining how this is supposed to work, but I still have no idea of how to do it.

As far as I know, you have to invoke the Open Firmware telnet package, pick an IP, connect the computer to the client via ethernet and telnet from there.

However, when I try to do it, it never works.

Has anyone here been able to successfully telnet into OF?
 
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Wow, I had no idea that this functionality existed.

Are you picking an IP address that works in your network setup? So if your router assigns everybody, 192.168.1.x, are you picking an IP address that is unused? That would be my first guess.
 
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Although I was not looking about how to telnet into my G4 (I was trying to find the address for a USB stick), the process can be worked out from the information in this thread:

How do I boot a Sawtooth (AGP) G4 from a USB stick?​

The one thing that I had to research a bit was how to use telnet on a Windows 10 computer. The software is/was still there, but has been turned off to provide less opportunity for it to be used as a way for a hacker to get into a Windows computer.

Once the telnet software has been turned on, connect the two computers with an Ethernet cable (disconnect the Mac from any other connection to the internet or local networks. Putting the macintosh into telnet mode, can be worked out from the information in the thread.

Once the mac is in telnet mode and the windows machine gives the correct command in the telnet program, the windows machine will use the Mac as a server and you can get whatever information you need, save the information on the windows machine as a text file, and print it out if you want.

Most of the information that you need is on the second page of the discussion, but it would be worthwhile to read both pages.

You will have to do some research, using the links that are given. I will be glad to help if needed.
 
w00t! Success.

Start Open Firmware:

Restart, hold down Option-Command-O-F while booting to boot into Open Firmware.

Check for the presence the TELNET package:

At the Open Firmware "0 > " prompt, type the following...
Code: 
dev /packages/telnet
I was happy to see the "ok" which means the telnet package is present in Open Firmware on my PowerPC Mac.

Start the TELNET server:

Type the following at the "0 > " prompt ...
Code: 
" enet:telnet,192.168.0.105" io

As NathanJHill mentioned, the IP address is the important part.

Start the TELNET client:

From the Terminal, on another computer on the same network, I typed:
Code: 
telnet 192.168.0.105

I got the "0 > " prompt, and could use Open Firmware remotely.

 
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YesWeCat said:
I have seen many small tutorials (https://flylib.com/books/en/3.126.1.41/1/) explaining how this is supposed to work, but I still have no idea of how to do it.

As far as I know, you have to invoke the Open Firmware telnet package, pick an IP, connect the computer to the client via ethernet and telnet from there.

However, when I try to do it, it never works.

Has anyone here been able to successfully telnet into OF?
Click to expand...
There's some Open Firmware documentation at https://developer.apple.com/library/archive/navigation/
Just search for Open Firmware.

I've usually used serial when doing Open Firmware (Power Mac 8600 era). For B&W G3, I used a serial adapter that connects to the internal modem port.
https://developer.apple.com/library/archive/technotes/tn/tn1061.html

A newer Power Mac won't have a serial port. For a PowerMac G5, I did use telnet. If you boot it, write down the IP address that you see in the network preferences panel and use the same address in Open Firmware. You might need to reboot and try again if it fails.
 
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joevt said:
A newer Power Mac won't have a serial port
Click to expand...
Just found this topic, really interesting (I like such low-level things, like firmware flashing, EFI shell & so on :) ). Btw, I have small 2-port PCI-Ex serial adapter, AFAIK - MOSCHIP based. I wonder if My QuadG5 would recognise it not only in OS but in OF prompt too? :) M.b. I'll try to perform some experiments.
 
Tratkazir_the_1st said:
Just found this topic, really interesting (I like such low-level things, like firmware flashing, EFI shell & so on :) ). Btw, I have small 2-port PCI-Ex serial adapter, AFAIK - MOSCHIP based. I wonder if My QuadG5 would recognise it not only in OS but in OF prompt too? :) M.b. I'll try to perform some experiments.
Click to expand...
The PCI-X serial card probably doesn't have an option rom with an Open Firmware driver for the serial port. In that case, a driver could be loaded from disk. You would have to read the Open Firmware (IEEE 1275-1994) specs and all the related specs. Some of them have sample code.
en.wikipedia.org

Open Firmware - Wikipedia

en.wikipedia.org en.wikipedia.org
 
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wnlewis said:
The one thing that I had to research a bit was how to use telnet on a Windows 10 computer. The software is/was still there, but has been turned off to provide less opportunity for it to be used as a way for a hacker to get into a Windows computer.
Click to expand...
A point of clarification. The standard telnet software which is available in Windows 10 is the client software and not the server software. Thus turning it on does not provide any additional opportunity for a hacker to hack into a Windows 10 system.
 
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Tratkazir_the_1st said:
Mine is PCI Express. Don't know, if it have some kind of ROM at all.
Click to expand...
I was confused by PCI-Ex. There's PCI Express and PCI-X. PCIe is the usual short form for PCI Express.

I know the Quad G5 has PCIe but I didn't put the two statements together. I have one but I enable only 3 CPUs using Open Firmware nvram boot-args because running 4 CPUs causes a hang.

Earlier Power Macs had PCI and AGP. I'm not sure about PCI-X so I looked it up. Here's a list: https://everymac.com/systems/apple/...5-number-type-speed-pci-pci-x-pcie-slots.html
 
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Option ROM in regards to Open Firmware is discussed at:
https://developer.apple.com/library/archive/technotes/tn/tn1044.html#//apple_ref/doc/uid/DTS10002886

In macOS, the lspci command of pciutils can be used to dump the registers of all PCI devices including the Expansion ROM base address.
sudo setpci -v -s '*:*.*' ROM_ADDRESS.l | sed -E '/0{8}/d'
sudo lspci -nnvvv | perl -0777 -nE 'while (/^(\w.*\n)(?:\t+(?!Expansion).*\n)*+(\t+Expansion.*\n)/gm) { print $1 . $2; }'

I don't think pciutils works on PowerPC Macs. I would like to make a version of pciutils that works with PowerPC and Apple Silicon Macs and Intel Macs - just need to make some changes to DirectHW.kext (I would like to make it a binary with all three architectures)
 
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Macbookprodude said:
What is the use of this ??? of what can be done with Telnet from OF in terms of anything really useful ?
Click to expand...
If you're doing development work in Open Firmware (to make a PC GPU work on PowerMac, or to make Mac OS X 10.4 work on old PowerMacs like the 8600, or to make Thunderbolt work on a PowerMac, etc.) then using Telnet makes things easier. you can paste Open Firmware commands into the Telnet session and copy output from the Telnet session. You can paste large amounts of code or data. The telnet session also has a scroll back buffer.
 
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Macbookprodude said:
No, I mean I would use my titanium under OF abd telnet to my Mac Pro.
Click to expand...
Oops. I got confused - I have a Power Mac G5 and a Mac Pro 2008 and sometimes forget that the Power Mac is not a Mac Pro.

I don't think macOS comes with Telnet anymore, but you can install it using Homebrew
https://brew.sh
https://osxdaily.com/2018/07/18/get-telnet-macos/

Or you can use a third party app that can act as a Telnet client
http://carnationsoftware.com/domains/MacWise/Index.html
 
m1mavrerick said:
A point of clarification. The standard telnet software which is available in Windows 10 is the client software and not the server software. Thus turning it on does not provide any additional opportunity for a hacker to hack into a Windows 10 system.
Click to expand...
You are probably correct. However, that is what I read from Microsoft. The telnet application, when turned on in Windows 10, still allows another computer to access the one, with telnet on, as a server. So that is why they turned it off. I did have to turn it on first, and that used to not be the case. It used to be readily available all the time. Again, I may have misread.
 
wnlewis said:
You are probably correct. However, that is what I read from Microsoft. The telnet application, when turned on in Windows 10, still allows another computer to access the one, with telnet on, as a server. So that is why they turned it off. I did have to turn it on first, and that used to not be the case. It used to be readily available all the time. Again, I may have misread.
Click to expand...
On Windows 10 the only default Telnet option is the client. It is specifically labelled "Telnet Client", there is no server option. To connect via telnet to a Windows 10 system one would need to install some third party telnet server software.
 
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Can the telnet in OF be used as a client too ?
( quite useless i know... But just to know, could be fun using a G5 or else just as a terminal for the lols)
 
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