How To Fix the “no hostkey alg” SSH Error Message on Older MacOSX

Author: erics, April 9th, 2025

The included, MacOSX-native ssh binary does not support newer SHA2 keys, so it gets the dreaded “no hostkey alg” or “kex_exchange_identification: read: Connection reset by peer” errors. To troubleshoot, check the sshd logs:

sudo log stream --style syslog --predicate 'process == "sshd"' --info

1	sudo log stream --style syslog --predicate 'process == "sshd"' --info

To fix that, install ssh via homebrew or macports and use that binary instead:

shell> ssh myserver ls
no hostkey alg

shell> which ssh
/usr/bin/ssh

shell> find /opt -name ssh 
/opt/local/bin/ssh
...

shell> /opt/local/bin/ssh -V
OpenSSH_9.9p2, OpenSSL 3.4.1 11 Feb 2025

shell> /opt/local/bin/ssh myserver
The authenticity of host 'myserver (1.2.3.4)' can't be established.
ED25519 key fingerprint is SHA256:Mmx6y1Z/example+/sbw.
This key is not known by any other names.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added 'myserver' (ED25519) to the list of known hosts.
Activate the web console with: systemctl enable --now cockpit.socket

Last login: Wed Apr  9 10:04:50 2025 from 4.5.6.7
shell> logout

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shell> ssh myserver ls

no hostkey alg

shell> which ssh

/usr/bin/ssh

shell> find /opt -name ssh

/opt/local/bin/ssh

...

shell> /opt/local/bin/ssh -V

OpenSSH_9.9p2, OpenSSL 3.4.1 11 Feb 2025

shell> /opt/local/bin/ssh myserver

The authenticity of host 'myserver (1.2.3.4)' can't be established.

ED25519 key fingerprint is SHA256:Mmx6y1Z/example+/sbw.

This key is not known by any other names.

Are you sure you want to continue connecting (yes/no/[fingerprint])? yes

Warning: Permanently added 'myserver' (ED25519) to the list of known hosts.

Activate the web console with: systemctl enable --now cockpit.socket

Last login: Wed Apr 9 10:04:50 2025 from 4.5.6.7

shell> logout

Categories: How-To's, Technology Tags: alg, Error, hostkey, howto, MacOS, macosx, no hostkey alg, ssh, tips | No comments

How To Fix perl: symbol lookup error: undefined symbol: Perl_xs_handshake

Author: erics, November 9th, 2023

This was caused by having the PERL5LIB environment variable set.

root@server1:/root # /etc/webmin/restart-by-force-kill
Force stopping Webmin server in /usr/libexec/webmin
/etc/webmin/.stop-init: line 10: kill: (10111) - No such process
Starting Webmin server in /usr/libexec/webmin
/usr/bin/perl: symbol lookup error: /root/perl5/lib/perl5/x86_64-linux-thread-multi/auto/Net/SSLeay/SSLeay.so: undefined symbol: Perl_ss_handshake

root@ server1:/root # unset PERL5LIB

root@ server1:/root # /etc/webmin/restart-by-force-kill
Force stopping Webmin server in /usr/libexec/webmin
/etc/webmin/.stop-init: line 10: kill: (10111) - No such process
Starting Webmin server in /usr/libexec/webmin

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root@server1:/root # /etc/webmin/restart-by-force-kill

Force stopping Webmin server in /usr/libexec/webmin

/etc/webmin/.stop-init: line 10: kill: (10111) - No such process

Starting Webmin server in /usr/libexec/webmin

/usr/bin/perl: symbol lookup error: /root/perl5/lib/perl5/x86_64-linux-thread-multi/auto/Net/SSLeay/SSLeay.so: undefined symbol: Perl_ss_handshake

root@ server1:/root # unset PERL5LIB

root@ server1:/root # /etc/webmin/restart-by-force-kill

Force stopping Webmin server in /usr/libexec/webmin

/etc/webmin/.stop-init: line 10: kill: (10111) - No such process

Starting Webmin server in /usr/libexec/webmin

Categories: How-To's, Technology Tags: env, environment, Error, howto, perl, Perl_xs_handshake, PERL5LIB, symbol lookup error, tips, undefined symbol, unset, Webmin | No comments

How To Fix Error “Wrong Fs Type, Bad Option, Bad Superblock” When Mounting a Filesystem

Author: erics, June 23rd, 2023

When trying to mount can XFS filestsen on an AWS instance, I got the error “mount: wrong fs type, bad option, bad superblock on /dev/sdh” Examine the volume’s UUID with the xfs_db command: shell> sudo xfs_db -c uuid /dev/nvme2n1 To fix the problem, you have two options… Temporary Solution Add nouuid mount option to temporarily […]

Categories: How-To's, Technology Tags: Bad Superblock, Error, Filesystem, howto, ifs_admin, ifs_db, mount, Mounting, tips, volume, Wrong Fs Type, XFS | No comments

How To Fix Error “Cannot open access to console, the root account is locked”

Author: erics, June 23rd, 2023

When trying to access the serial console on AWS, I got the following error: Cannot open access to console, the root account is locked Since I had edited /etc/fstab, the host would not boot. The only way to fix this problem is to unmount the root volume from the affected instance, mount it on another […]

Categories: How-To's, Technology Tags: /etc/fstab, AWS, Console, Error, fstab, howto, Locked, root, tips | No comments

How To Fix SSH Permission Denied From macOS Ventura To Amazon Linux

Author: erics, May 9th, 2023

I have been using RSA SSH keys forever to login to my various AWS EC2 instances. With macOS Ventura 13.3.1 ssh failed with the “Permission Denied” error. Using ssh -vvv, I saw that the RSA key was now being rejected. After much research, I decided to implement new keys on the client (Ventura) side using […]

Categories: How-To's, Technology Tags: AWS, denied, ed25519, Error, Generate, howto, key, Linux, MacOS, Permission Denied, public, Public Key, ssh, ssh-keygen, sshd, tips, Ventura | No comments

How To Fix “iCloud Account Could Not Be Removed” Error on OS X Yosemite 10.10.5

Author: erics, November 24th, 2022

PROBLEM: Unable to sign out of iCloud on OSX Yosemite or disable Keychain SOLUTION: Delete the following, then reboot:

~/Library/Application Support/iCloud/
~/Library/Preferences/Mobile*.plist

1 2	~/Library/Application Support/iCloud/ ~/Library/Preferences/Mobile*.plist

Categories: Technology Tags: 10.10.5, Delete, Error, howto, iCloud, Library, macosx, OSX, plist, Preferences, Remove, tips, Yosemite | No comments

How To Fix WPDataTables Error “You are trying to load a table of an unknown type” in WordPress

Author: erics, September 7th, 2022

If you get the following error in WordPress when using the WPDataTables plugin, follow these steps to fix it: “You are trying to load a table of an unknown type. Probably you did not activate the addon which is required to use this table type.” SOLUTION SUMMARY: You must update the plugin files manually, deactivate […]

Categories: Technology Tags: Activate, Deactivaate, Error, Fix, howto, Plugin, Reactivate, tips, update, upgrade, WordPress, WPDataTables | No comments

How To Solve Grafana Error “failed to load its application files”

Author: erics, February 23rd, 2022

Try a newer browser before anything else! I was using an older version of Safari on Mac and got this:

If you're seeing this Grafana has failed to load its application files

1. This could be caused by your reverse proxy settings.
2. If you host grafana under subpath make sure your grafana.ini root_url setting includes subpath. If not using a reverse proxy make sure to set serve_from_sub_path to true.
3. If you have a local dev build make sure you build frontend using: yarn start, yarn start:hot, or yarn build
4. Sometimes restarting grafana-server can help
5. Check if you are using a non-supported browser. For more information, refer to the list of supported browsers.

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If you're seeing this Grafana has failed to load its application files

1. This could be caused by your reverse proxy settings.

2. If you host grafana under subpath make sure your grafana.ini root_url setting includes subpath. If not using a reverse proxy make sure to set serve_from_sub_path to true.

3. If you have a local dev build make sure you build frontend using: yarn start, yarn start:hot, or yarn build

4. Sometimes restarting grafana-server can help

5. Check if you are using a non-supported browser. For more information, refer to the list of supported browsers.

I switched to the latest version of FireFox and was fine.

Categories: How-To's, Technology Tags: Browser, Error, Failed, Failed to Load, Firefox, Grafana, howto, Safari, tips | No comments

How To Force Postfix To Use Only IPv4

Author: erics, August 12th, 2021

vi /etc/postfix/main.cf

#inet_protocols = all
inet_protocols = ipv4

1 2	#inet_protocols = all inet_protocols = ipv4

service postfix restart

Categories: How-To's, Technology Tags: Email, Error, Gmail, howto, IPv4, IPv6, PostFix, Protocol, tips | No comments

How To Fix aws Command Error “You must specify a region”

Author: erics, July 29th, 2021

I was getting error “You must specify a region” when running any aws CLI command. The fix: Using the aws command:

aws configure set region us-east-1 --profile demo

1	aws configure set region us-east-1 --profile demo

which will automatically add the following to the file ~/.aws/config:

[profile demo]
region = us-east-1

1 2	[profile demo] region = us-east-1

You many simply edit the ~/.aws/config file yourself and append the same thing:

vi ~/.aws/config

[profile demo]
region = us-east-1

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vi ~/.aws/config

[profile demo]

region = us-east-1

Categories: How-To's, Technology Tags: AWS, aws cli, aws command, aws configure, aws set, cli, Command, Config, configure, Error, Region, You must specify a region | No comments

How To Fix the “no hostkey alg” SSH Error Message on Older MacOSX

How To Fix perl: symbol lookup error: undefined symbol: Perl_xs_handshake

How To Fix Error “Wrong Fs Type, Bad Option, Bad Superblock” When Mounting a Filesystem

How To Fix Error “Cannot open access to console, the root account is locked”

How To Fix SSH Permission Denied From macOS Ventura To Amazon Linux

How To Fix “iCloud Account Could Not Be Removed” Error on OS X Yosemite 10.10.5

How To Fix WPDataTables Error “You are trying to load a table of an unknown type” in WordPress

How To Solve Grafana Error “failed to load its application files”

How To Force Postfix To Use Only IPv4

How To Fix aws Command Error “You must specify a region”

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