Use su with ssh X-forwarding

This is a shameless ripoff of Howto use su with ssh x-forwarding [coderwall.com]

If you ssh to a server and want to do X forwarding, make sure the server allows it in /etc/ssh/sshd_config:

X11Forwarding yes

And then your ssh command should include -X, or make sure your ~/.ssh/config includes:

ForwardX11 yes

Command:

ssh -X servername

And once on the server, prepare your xauth file to be shared the other user before switching and merging it.

xauth extract /tmp/x $DISPLAY
chmod 0644 /tmp/x
su otherusername
xauth merge /tmp/x

References

Web searches

ssh x forwarding with su

sshd_config match negate address

tl;dr

Match Address *,!192.168.1.0/24

Negating address in match statement in sshd_config

I was locking down my ssh server configuration on a host, so that it will not accept password auth from outside a certain IP address range.
I had to learn how to get the Match Address directive to work with a negation. To make it work, you need to insert a wildcard before you then state the exclusion.

Match Address *,!192.168.1.0/24

And then I added the directives for this matched IP address range.

   AuthenticationMethods publickey
   PubkeyAuthentication yes
   PasswordAuthentication no
   X11Forwarding no

References

Weblinks

  1. https://serverfault.com/questions/408284/how-can-the-address-condition-in-a-match-conditional-block-in-sshd-config-be-neg

Man pages

  1. sshd_config
  2. ssh_config

sshd_config Match AD group

Overview

Last updated: 2019-01-14

I use CentOS 7. One of the biggest reasons I join my servers to Active Directory is for the users and groups. Getting sshd_config to work with AD-defined groups is easy and just needs the smallest amount of work.

If you want to use sftp, and have rules for just a specific AD group, you need to specify the group name exactly as it is cased.
[root@amazon|/var/log]# getent group Web_Dev_Grp
web_dev_grp:*:5829038:asmith,rltompki,fkowalks,bangel,lfrederi

So use the “web_dev_grp” as shown in your sshd_config:
Match Group web_dev_grp
ChrootDirectory /var/www
ForceCommand internal-sftp

If you want to match multiple groups, you can use this format:
Match Group web_dev_grp,linux_admins_grp

Be sure to read ssh_config(5) on PATTERNS and sshd_config(5) on Match for more details.