=====RHEL=====

====PATCH====

  yum repolist all                                        #List all repos
  /etc/yum.repos.d                                        #Repo folder
  yum repolist all |grep enabled                          #List active repos
  yum repolist
  yum makecache 
  yum-config-manager --enable repository-xy
  yum-config-manager --disable repository-xy
  subscription-manager repos --disable repository-xy      #RHEL7 
  subscription-manager repos --disable repository-xy      #RHEL7
  yum check-update
  yum check-update --security
  yum clean all
  rm -rf /var/cache/yum
  yum updateinfo
  yum update
  yum update -y
  yum update --skip-broken
  yum update --security
  yum-complete-transaction
  zypper dist-upgrade
  zypper clean -a
  rpm -qa --last                                          #shows last applied packages
  
====rpm database broken====

To solve a broken rpm-database:

  yum info expat
  mkdir /var/lib/rpm/backup
  cp -a /var/lib/rpm/__db* /var/lib/rpm/backup/
  rm -f /var/lib/rpm/__db.[0-9][0-9]*
  rpm --quiet -qa
  rpm --rebuilddb
  yum clean all
  yum info expat
  rm -rf /var/lib/rpm/backup
or
  mv /var/lib/rpm/__db* /tmp/
  rpm --rebuilddb
  yum clean all
  
==== Systeminfo ====

  lsb_release -d                                          #>= RHEL7
  cat /etc/redhat-release                                 #<= RHEL6
  
==== Search & Install ====

  yum search package
  yum search all package
  yum list java*                                                                                                       #search versions, getting also repos which contain the package
  yum list java-1.8.0-ibm*
  yum reinstall package
  yum install package
  yum erase httpd httpd-tools
  yum -y --nogpgcheck install nrpe nagios-plugins-disk nagios-plugins-load nagios-plugins-swap nagios-plugins-procs
  yum reinstall --downloadonly --downloaddir=/tmp kernel-debuginfo glibc-langpack-de-2.28-225.el8.x86_64.rpm
  pkcon search name package                                                                                            #shows all available versions of a package

==== Satellite ====

  /etc/init.d/taskomatic restart 
  rhn_check -vvvv

Add Channel:

  cdn-sync --list-channels |grep dotnet
  cdn-sync --channel rhel-x86_64-server-7-dotnet-1

=== Satellite Clients ===

  rhn_check -vvvvv
  /usr/sbin/rhn_check -vvvvv
  rhnsd               #Service to interact with Satellite
  rhn-profile-sync    #Sync package list with Satellite

=== RHEVM ===

  engine-upgrade-check 
  yum update ovirt\*setup\* 
  engine-setup 


  
==== Firewall ====
=== RHEL7 ===

== Add Rules ==

Open http(s):

  firewall-cmd --zone=public --add-service=http --permanent
  firewall-cmd --zone=public --add-service=https --permanent
  
Activate:
  firewall-cmd --reload

Test:
  iptables -L | grep https
  iptables -L | grep http

Example-Output:
  [root@testhost ~]# iptables -L |grep https
  ACCEPT     tcp  --  anywhere             anywhere             tcp dpt:https ctstate NEW

Open firewall port tcp/2888 to zone "public" to anybody:
  firewall-cmd --zone=public --add-port=2888/tcp --permanent
  firewall-cmd --reload

Open firewall port for zone "public" to particularry IP:
  firewall-cmd --permanent --zone=public --add-rich-rule='rule family="ipv4" source address="136.230.49.56/30" port protocol="tcp" port="9200" accept'
  firewall-cmd --permanent --zone=public --add-rich-rule='rule family="ipv4" source address="136.230.49.56/32" port protocol="tcp" port="9200" accept'

List zones:
  firewall-cmd --list-all-zones

Show zone content:
  firewall-cmd --info-zone=public
  
== Delete Rules ==

Remove a rule, **without** restriction:

  firewall-cmd --zone=public --remove-port=80/tcp
  
Remove a rule, **with** restriction:

  firewall-cmd --permanent --zone=public --remove-rich-rule='rule family="ipv4" source address="136.230.49.56/30" port protocol="tcp" port="8480" accept'
  firewall-cmd --permanent --zone=public --remove-rich-rule='rule family="ipv4" source address="136.230.230.196/32" port protocol="tcp" port="8480" accept'
  
Remove a servicebased rule:
  
  firewall-cmd --zone=public --remove-service=http
  
Activate:

  firewall-cmd --reload
  
If a rule can´t be removed (even if firewall-cmd shows "success") it´s possible to remove it inside the configuration file:
  
  /etc/firewalld/zones/public.xml

Afterwards you have to restart the firewall service:

  systemctl restart firewalld.service

===RHEL6===

  lokkit --port=80:tcp --update
  lokkit --port=443:tcp --update
  
**Config file:**
<code>
/etc/sysconfig/system-config-firewall
# Configuration file for system-config-firewall

--enabled
--port=80:tcp
</code>

Or:

  /etc/sysconfig/iptables

Restart iptables:

  /etc/init.d/iptables restart
  
Check:

<code>
iptables -L -n |grep 80
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0           state NEW tcp dpt:80
</code>

  
==== NETWORK ====

===RHEL6===

**Related files:**

  /etc/hosts
  /etc/sysconfig/network
  /etc/sysconfig/network-scripts/ifcfg-eth0
  /etc/resolv.conf
  
**/etc/sysconfig/network-scripts/ifcfg-eth0:**
<code>
DEVICE=eth0
HWADDR=00:0c:29:9c:37:ba
TYPE=Ethernet
UUID=a23f59eb-0246-451f-bb56-5a256403b722
ONBOOT=yes
NM_CONTROLLED=yes
BOOTPROTO=none
IPADDR=192.168.0.5
NETMASK=255.255.255.0
DNS2=8.8.8.8
GATEWAY=192.168.0.2
DNS1=10.2.206.102
IPV6INIT=no
</code>
**/etc/sysconfig/network:**
<code>
NETWORKING=yes
HOSTNAME=RHEL6-6
</code>

===RHEL7===

  /etc/hostname
  systemctl restart systemd-hostnamed
  hostnamectl set-hostname name
  hostnamectl status

====Register====

  subscription-manager config --server.proxy_hostname=proxy.example.com --server.proxy_port=8080 --server.proxy_user=admin --server.proxy_password=secret
  subscription-manager register --username user@test.de --password mysecret
  subscription-manager attach --auto
  
====Certificate====

To add a certificate in the simple PEM or DER file formats to the list of CAs trusted on the system, copy the certificate file to the /usr/share/pki/ca-trust-source/anchors/ or /etc/pki/ca-trust/source/anchors/ directory. To update the system-wide trust store configuration, use the update-ca-trust command, for example: 

  cp ~/certificate-trust-examples/Cert-trust-test-ca.pem /usr/share/pki/ca-trust-source/anchors/
  update-ca-trust