• OSI Models
• TCP/IP
• Routing Bridging and NAT
• Firewalls and Ports
• Basic Utils - netstat,ping,mtr,nc,ip
• DNS
• Load Balancing
• Proxies
• SSH Port forwarding
• TLS Encryption
• CIDR | Subnet Math | General Concepts of maths
• VPC's
• Firewall Concepts
• SSL|TLS

• The moment you see an ip address, you should be able to answer 2 questions

1. is this is a public ip addresss or a private ip address
2. what class of Ip address is this.

– Every company, website has a public ip address (1 or 2 or 3 ) … max 10 – these public ip addresses are provided by ISP providers – these have a charge attached to it.

– every company has a range of private ip addresses – these are free to use – configured and manatained by internal network administrator

Ip address

[1-255].[0-255].[0-255].[0-255] 1.1.1.1 100.126.10.240 50.111.175.250

100.0.1.2

Classes of Ipaddress PUBLIC RANGE PRIVATE RANGE class A = [1.0.0.1 to 126.255.255.254][10.0.0.0 to 10.255.255.255] Class B = [128.1.0.1 to 191.255.255.254][172.16.0.0 to 172.31.255.255] Class c = [192.0.1.1 to 223.255.254.254][192.168.0.0 to 192.168.255.255] Class D — not used Class E — not used 1 – Public 2 – public 3 – public 4 – public 5 – public 6 – private 7 – public 8 – public 9 – public 10 – public versions of Ip address Ipv4 64bit Ipv6 128 bit 127.0.0.1 to 127.255.255.255 = these are loop back address. every computer will have this address names as “loopback” this is used for testing connectivity and some application services. 169.X.X.X – if a computer|server doesnt get a ip address from the dhcp server or router, this ip address is auto assigned by the system NIC card. this cannot be used to communicate either privately or publicly.

network devices

1. routers – communicate based on Ip address – these are called as layer 3 devices

2. switches – layer 2 switches communicate based on MAC address – layer 3 switches communicate based on IP address

3. hubs – these are repeators – not intelligent devices like routers and switches

4. Firewall

5. load balancers

Vendors – cisco router – Juniper – citrix -> netscaler – home user – netgear Additional learns – subnetting – nating – pating – Switching protocols – spannning tree protocol – RSVP

– routing protocols – RIP V1 – EIGRP – OSPF – RIP V2 – BGP

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Assignments

1. read about basic networking concepts
2. learn 50 most commonly used linux commands, learn vim
3. learn how to install a web server in Centos | Ubuntu | windows
4. OSI layers

DevOps – Server and networking basics:

Operating system Windows – Desktop editions – windows XP, 7, 8, 10, vista (home, professional, ultimate) – server edition – Windows 2000, 2003, 2008, 2012 (standard, Enterpise, datacenter) (32 bit or 64 bit)

Linux | Unix (Flavors)

Desktop – Ubuntu, RHEL 7. server – ubuntu | Debian, (OS) | version 17, most used is 12.04 and 14.04 (LTS) – Long term support – RHEL (Paid) | Centos (OS) – unix – fedora – suse – mandraike – solaris – slackware – gentoo

• Multi threading operating system – multiple users can log into the same machine at same time and work – there will be no conflict of resouces (RAM, CPU etc )

Mac vmware – virtualization technology – It is a hypervisor Operating system – ampligies the resources that are given to it and will allocate to the respective vms inside it

What is diff between a desktop and server

– desktop is single users – server is multiple services What are the services that a server can | will provide

– webserver – webserver – internal and external websites – windows = IIS (internet information services) – Linux = RHEL = Httpd, ubuntu = apache2 – ftp – File transfer protocol – huge or bulk file transfers – DNS – Domain Name service – Ip address to Name and Name to ip address – save the details in DNS server as records – study about types of records – AAAA – CNAME – MX – WWW – pointer

– there are global DNS server which are maintainer by internet board – there are called as root server – when you join a company – your desktops are servers are pointed to Local DNS servers which are installed, configured, managed by your IT team or local administrator – internal resouces are having a DNS record. – other configurations in DNS server – zones – Primary and secondary – master and slave – DHCP dynamic host control protocol – how to assign a static ip address in windows

– Mail windows – Exchange linux – zimra, sendmail, postfix

– Print – AD | LDAP – Samba – File Server – Application server

$ watch ss -tp                               # Network connections
$ netstat -ant                               # Tcp connections -anu=udp
$ netstat -tulpn                             # Connections with PIDs
$ lsof -i                                    # Established connections
$ smb:// ip /share                           # Access windows smb share
$ share user x.x.x.x c$                      # Mount Windows share
$ smbclient -0 user\\\\ ip \\ share          # SMB connect
$ ifconfig eth# ip / cidr                    # Set IP and netmask
$ ifconfig ethO:l ip / cidr                  # Set virtual interface
$ route add default gw gw_ip                 # Set GW
$ ifconfig eth# mtu [size]                   # Change MTU size
$ export MAC=xx: xx: xx: xx: xx: xx          # Change MAC 
$ ifconfig int hw ether MAC                  # Change MAC
$ macchanger -m MAC int                      # Backtrack MAC changer
$ iwlist int scan                            # Built-in wifi scanner
$ dig -x ip                                  # Domain lookup for IP
$ host ip                                    # Domain lookup for IP
$ host -t SRV _ service _tcp.url.com         # Domain SRV lookup
$ dig @ ip domain -t AXFR                    # DNS Zone Xfer
$ host -l domain namesvr                     # DNS Zone Xfer
$ ip xfrm state list                         # Print existing VPN keys
$ ip addr add ip / cidr dev ethO             # Adds 'hidden' interface
$ /var/log/messages | grep DHCP              # List DHCP assignments
$ tcpkill host ip and port port              # Block ip:port
$ echo "1" /proc/sys/net/ipv4/ip_forward     # Turn on IP Forwarding
$ echo "nameserver x.x.x.x" /etc/resolv.conf # Add DNS Server

• Networking for Devops