Friday, May 04, 2018

SSH Secure Shell Connections with MacWise and High Sierra

If you cannot connect to a host using secure shell (ssh) with MacWise, it could be a problem with High Sierra and cipher keys.
You may get a message similar to this when trying to connect to the host:

Unable to negotiate with xxx.xxx.xxx.xxx port 22: no matching cipher found. Their offer: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,
aes192-cbc,aes256-cbc,rijndael-cbc

This is not a problem with MacWise. It is an issue with MacOS High Sierra 10.13
You can get around this problem by specifying a cipher in the Secure Shell Connection settings in MacWise.

Select Secure Shell Connection... from the Connection Menu in MacWise.
Then enter a cipher by using the -c option in the Additional Login Options field.
For instance, -c aes256-cbc
That option would use the  cipher, aes256-cbc

Currently, High Sierra supports these ciphers:
3des-cbc
aes128-cbc
aes192-cbc
aes256-cbc
rijndael-cbc@lysator.liu.se
aes128-ctr
aes192-ctr
aes256-ctr
aes128-gcm@openssh.com
aes256-gcm@openssh.com

chacha20-poly1305@openssh.com

You can verify this by opening the terminal app and entering
ssh -Q cipher

Your host may not support all of the ciphers that High Sierra supports.
So, when you connect to the host and it responds with "no matching cipher found", you can look at the list of ciphers that it offers and use one of those that high sierra also supports.



Friday, January 05, 2018

Crash when upgrading to High Sierra from older versions of MacWise

Upgrading to High Sierra with versions of MacWise prior to 16.2.3 could possibly cause abnormally large window sizes and a crash that corrupted the MacWise settings file.

It is unknown why this happens and it seems to be a problem on a low percentage of Macs.
Version 16.2.3 or later fixes this problem by detecting incorrect window sizes and sets them back to default sizes.

If possible, you should upgrade to MacWise 16.2.3 or later before installing Mac OS High Sierra or later to avoid the crash.

Wednesday, January 03, 2018

Function Keys and Arrow Keys with MacWise using Telnet and Kermit

MacOS High Sierra 10.13 removed telnet.
By default, MacWise version 16 now uses Kermit for telnet connections when it detects MacOS 10.13 or later.
It also enables two Kermit options by default:
"Use SLnet options for Kermit"  and "Echo Kermit Characters"

Not all host servers work properly with those two options.
If you are getting double characters on your screen, then uncheck "Echo Kermit Characters"

If your arrow keys and function keys do not work, then uncheck "Use SLnet options for Kermit"
Note that other factors can cause arrow keys and function keys not to work.

If you cannot log into your host, then put a checkmark on "Use SLnet options for Kermit"
You may see the following errors when opening a connection if it is unchecked:
Negotiations...
The Telnet server is not sending required responses
Telnet waiting for response to WILL KERMIT

Telnet waiting for response to DO KERMIT