{{tag>Brouillon Sécurité SSH}}

= Changer le nom ou l'IP d'un serveur GNU/Linux

=== Template VM
Voir  : 
* https://wiki.debian.org/HowTo/ChangeHostname
* https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Virtualization/3.5/html/User_Guide/sect-Templates.html
* https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.0/html/virtual_machine_management_guide/chap-templates

RedHat registration
<code bash>
subscription-manager unregister
subscription-manager remove --all
subscription-manager clean
</code>



Hostname
<code bash>
hostnamectl set-hostname localhost.localdomain
</code>

Udev
<code bash>
rm -rf /etc/udev/rules.d/70-*
</code>

machine-id
<code bash>
chmod 777 /etc/machine-id
> /etc/machine-id
chmod 444 /etc/machine-id
</code>

Voir aussi : 
  * /sys/class/dmi/id/product_uuid
  * /sys/class/dmi/id/product_name
Qui peuvent être copiés sur l'image cible pour savoir sur quel matériel l'image a été créée.

Réseau
<code bash>
rm -f /etc/sysconfig/network-scripts/ifcfg-eth*
#sed -i '/UUID/c\UUID=' /etc/sysconfig/network-scripts/ifcfg-eth0
#sed -i '/HWADDR/c\HWADDR=' /etc/sysconfig/network-scripts/ifcfg-eth0
</code>

Clean /var/log/
<code bash>
find /var/log/ -type f -name "*[-_]2018[0-9][1-9][0-9][1-9]*" -delete
find /var/log/ -type f -name "*.old" -delete

rm -rf /var/log/journal/*
systemd-tmpfiles --create --prefix /var/log/journal
systemctl restart systemd-journald

#for fic in $(find /var/log/ -type f) ; do > $fic ; done
find /var/log/ -type f -exec /bin/sh -c '>{}' \;

rm /var/log/sysstat/* -rf
find /var/log/ -type f -name "*.*[0-9]" -delete
find /var/log/ -type f -name "*.gz" -delete
</code>

<code bash>
# Debian
killall dhclient
#rm /var/lib/dhcp/dhclient.eth0.leases
rm -f /var/lib/dhcp/*
killall ntpd
rm /run/ntp.conf.dhcp
</code>

Autres RedHat
<code bash>
# systemctl enable initial-setup.service
# sys-unconfig
# touch /.unconfigured
</code>


Bash history
<code bash>
rm -f /root/.bash_history
rm -f /home/*/.bash_history
history -c && history -w
</code>

Poweroff
<code bash>
poweroff
</code>




=== Renommer un serveur

<code bash>
grep $(hostname -s) -Ril /etc/
</code>

Fichier à modifier
* /etc/machine-id
* /etc/hosts
* /etc/hostname
* /etc/mailname
* /etc/exim4/update-exim4.conf.conf
* /etc/machine-info
* /etc/sysconfig/network

<code bash>
rm -f /etc/machine-id
systemd-machine-id-setup
</code>

SSH


<code bash>
dpkg-reconfigure openssh-server
</code>

Ou

<code bash>
# CHANGER LE HOSTNAME AVANT !

#rm /etc/ssh/ssh_host_rsa_key /etc/ssh/ssh_host_rsa_key.pub
#rm /etc/ssh/ssh_host_dsa_key /etc/ssh/ssh_host_dsa_key.pub
#rm /etc/ssh/ssh_host_ecdsa_key /etc/ssh/ssh_host_ecdsa_key.pub
#ssh-keygen -h -N '' -t rsa -f /etc/ssh/ssh_host_rsa_key
#ssh-keygen -h -N '' -t dsa -f /etc/ssh/ssh_host_dsa_key
#ssh-keygen -h -N '' -t ecdsa -f /etc/ssh/ssh_host_ecdsa_key

rm -f /etc/ssh/ssh_host_*
/usr/bin/ssh-keygen -A
</code>


<code bash>
hostnamectl set-hostname nouveau-nom
systemctl restart systemd-hostnamed
</code>


=== Changement d'adresse IP

Fichier à modifier
* /etc/resolv.conf
* /etc/systemd/resolved.conf
* /etc/network/interfaces

=== Conf client DNS

<code - /etc/resolv.conf>
#domain acme.local
search acme.local
options rotate timeout:1 retries:1
#options edns0
nameserver 192.168.10.253
nameserver 192.168.11.253
</code>

Avec SystemD voir ''/etc/systemd/resolved.conf''


=== Généralités

Parfois il faut aussi modifier les fichiers suivants
* /etc/motd
* /etc/issue

Voir [[http://alog.ipduh.com/2014/12/clone-kvm-guest.html]]