TDDI41 Grundläggande systemadministration

Ht1-Ht2 2024

Lectures

• Introduction TDDI41/TDP031
• Lecture 2 Networking
• Lecture 3- Directory Services (LDAP,DNS)
• BIND and Storage
• Lecture 4 - Configuration Mangement
• Network revisted

  Router settings:
  

  	      echo 1 > /proc/sys/net/ipv4/ip_forward
  
  	      nft add table ip nat
  	      nft add chain ip nat postrouting { type nat hook postrouting priority 100 ; }
  	      nft add rule ip nat postrouting oif "ens3" masquerade
  
  
  	    

  
  Setting ip-address example (/etc/network/interfaces)
  

  	      auto lo eth0
  	      iface lo inet loopback
  
  	      iface eth0 inet static
  	        address 192.168.100.2
  	        netmask 255.255.255.240
  	        gateway 192.168.100.1
  
  	    

• SSH tips
  • Passwordless login

                  #Generate key(s) (on the machine you want to ssh from)
                  router%>ssh-keygen
                  #copy pulic keys to the machines you want to ssh to
                  router%>ssh-copy-id -i ~/.ssh/id_rsa.pub root@machine
                

  • SSH Jumphost

                  #You can connect to a target machine (server,client1/2) by using your router as a Jumphost
                  ida%>ssh -J root@127.0.0.1:2220 root@192.168.1.2
                  #To be able to do this without using password you need to
                  #copy your public-key from your IDA-folder to all your machines.
                

  • SSH config

                    #
                  

• DNS basics
  

  named.conf.local

  
  zone "anders.rune.com" {
  	type master;
  	file "/etc/bind/zones/anders.rune.com";
  };
  
  zone "100.168.192.in-addr.arpa" {
  	type master;
  	file "/etc/bind/zones/reverse/rev.100.168.192";
  };
  

  anders.rune.com

  root@uml-root-jessie:~# cat /etc/bind/zones/anders.rune.com
  $TTL 1h
  @ 	IN	SOA ns1.anders.rune.com. andla.anders.rune.com.(
  		201811223 ; SERIAL
  		2h	  ; Refresh
  		1h	  ; Retry
  		1w	  ; Expire
  		1h	) ;Minium
  
  ;
  @	IN 	NS 	ns1.anders.rune.com.
  @	IN 	NS 	ns2.anders.rune.com.
  
  anders.rune.com. IN 	A 	192.168.100.2
  ns1		 IN 	A	192.168.100.2
  ns2		 IN	A	192.168.100.2
  server		 IN	CNAME	anders.rune.com.
  client1		 IN	A	192.168.100.11
  client2		 IN	A	192.168.100.12
  
  lars.anders.rune.com. IN NS	ns1.lars.anders.rune.com.
  ns1.lars.anders.rune.com. A 192.168.100.20
  

Sidansvarig: Anders Fröberg
Senast uppdaterad: 2025-04-29