11/12/15UB Fall 2015 CSE565: S. Upadhyaya Lec 22.1 CSE565: Computer Security Lecture 22 IP Basics Shambhu Upadhyaya Computer Science & Eng. University at Buffalo Buffalo, New York 14260

11/12/15UB Fall 2015 Outline  IP (November 12, 2015)  IP Security architecture (November 17, 2015)  Authentication Header  Key Management CSE565: S. Upadhyaya Lec 22.2

11/12/15UB Fall 2015 The Role of IP  IP provides functionality to interconnected devices across multiple networks  IP is implemented in each end system and routers  The routers along the way must cope up with:  Addressing schemes (IEEE 802 vs. X.25)  Maximum packet sizes (fragmentation)  Interfaces (hardware/software)  Reliability (should be independent of it) CSE565: S. Upadhyaya Lec 22.3

11/12/15UB Fall 2015 Some Issues of IP  Data at higher level are encapsulated in a PDU (protocol data unit)  PDU is passed through one or more networks and connected routers and to the end system  IP header must contain all the necessary addresses  No reliability assurance  Intermediate subnets need not be concerned about reliability requirements  TCP takes care of reliability CSE565: S. Upadhyaya Lec 22.4

11/12/15UB Fall 2015 Configuration of TCP/IP CSE565: S. Upadhyaya Lec 22.5 Figure: Configuration for TCP/IP Example

11/12/15UB Fall 2015 Operation of Routers  IP is implemented in all end systems and routers  End systems must have compatible protocols above IP  Routers need only have up through IP CSE565: S. Upadhyaya Lec 22.6

11/12/15UB Fall 2015 Operation, Contd.  Block of data from X to Y  PDU is created and IP layer attaches a header (global Internet address of Y)  Since Y is on another network, the packet needs to be sent to router 1 in the form of an LLC PDU  Upon receiving, MAC layer constructs a MAC packet and sticks in the address of router 1  After examination, router 1 routes packets to router 2 (wrapping in another format if necessary)  Router 2 strips off header to determine that the IP packet is destined to Y  Router 2 creates a packet with destination address of Y and sends it onto the LAN  Y removes all headers and forwards data to upper CSE565: S. Upadhyaya Lec 22.7

Router, Switch and Hub  Router is like a computer - acts as gateway  Joins together multiple LANs to a WAN  Works at layer 3 of OSI  Switch is less sophisticated  Must designate a computer as a gateway  Works at layer 2 of OSI  Connects devices to form a LAN  Hub is used to connect segments of LAN  Works at layer 1 of OSI  It is like a splitter 11/12/15UB Fall 2015 CSE565: S. Upadhyaya Lec 22.8

11/12/15UB Fall 2015 IPv4  20 bytes or 160 bits (minimum)  32 bit address (4.3 billion IP addresses)  Study shows that available address space would not last long  In April 2014, North American Registry for Internet Numbers (ARIN), announced it had reached "phase 4" of its IPv4 countdown plan, with fewer than 17 million IPv4 addresses remaining CSE565: S. Upadhyaya Lec 22.9

The Grim Story of IPv4  ARIN had fewer than 17M addresses left last year  ARIN has tightened the address supply and now has run out of it  APNIC (Asia-Pacific registry) reached the 17M threshold four years ago  RIPE NCC (Europe) reached its threshold less than three years ago  Latin America and Caribbean directories in similar status  AfriNIC in Africa is continuing to supply IPv4 addresses 11/12/15UB Fall 2015 CSE565: S. Upadhyaya Lec 22.10

How Did We Get Here  In the 80’s protocols used 16 bit addresses  The Internet growth was not predicted well  Making the addresses a meager 32 bits was a big failure of imagination  It took only a decade before IP address numbering ran into trouble  Initially a class system – A,B,C to handle networks and hosts  This was later abolished, which improved situation a bit 11/12/15UB Fall 2015 CSE565: S. Upadhyaya Lec 22.11

Use of IP Address Space 11/12/15UB Fall 2015 CSE565: S. Upadhyaya Lec 22.12

Classless Regime  Deployment of new IP address space slowed down to a much more sustainable pace as the Internet boomed in late 90’s  Around 2000  More and more broadband always-on connections  Few years later  Millions of smartphones continuously connected  Day was saved by NAT adoption 11/12/15UB Fall 2015 CSE565: S. Upadhyaya Lec 22.13

NAT Details  These days people use more than one PC  ISPs provide more IP addresses for a fee  Cheaper solution is to share a single add.  With NAT, you get IP addresses from /8, /12, or /16 address ranges set aside for private use  A home router that implements NAT then translates between the internal address and the regular, public address given out by the ISP 11/12/15UB Fall 2015 CSE565: S. Upadhyaya Lec 22.14

The Stanford vs. China Story  More than a decade ago, Stanford held more IPv4 addresses than the entire China  However, by 2006, organizations in China held a total of 98M IP addresses  Today, China has given out a total of 330M addresses  China is the second largest holder of IPv4 addresses, behind the US with billion  China: 1 address for 4, US: 1 user 5 addresses  If each user in the world deserves one, we have a problem! 11/12/15UB Fall 2015 CSE565: S. Upadhyaya Lec 22.15

IP Addresses Held By Country 11/12/15UB Fall 2015 CSE565: S. Upadhyaya Lec 22.16

So, What Now?  IPv6 is the solution  Read the article: “With the Americas running out of IPv4, it’s official: The Internet is full” by Iljitsch van Beijnum at arstechnica.com  ( technology/2014/06/with-the-americas- running-out-of-ipv4-its-official-the-internet- is-full/) technology/2014/06/with-the-americas- running-out-of-ipv4-its-official-the-internet- is-full/  Also read: technology/2015/07/us-exhausts-new-ipv4- addresses-waitlist-begins/ technology/2015/07/us-exhausts-new-ipv4- addresses-waitlist-begins/ 11/12/15UB Fall 2015 CSE565: S. Upadhyaya Lec 22.17

11/12/15UB Fall 2015 IPv6  Fixed length of 40 octets  128 bit addresses ( 5x10 28 addresses for each of the 7 billion people)  U.S. government specified network backbones at federal agencies must deploy IPv6 by 2008 – the adoption is slow due to lack of client base  Major backbone networks – Amazon, Comcast, HSBC, Akamai, Verizon, etc. have deployed IPv6 CSE565: S. Upadhyaya Lec 22.18

Summary  IPv4 has already run out of address space  IPv6 initiative started in 1995 but adoption is slow, will become main stream soon  Products such as Microsoft OS have support for IPv6 and are enabled by default  IPv6 has no backward compatibility since headers are significantly different  You need to run dual stacks to serve both types of networks  Situation is similar to WEP and RSN in the wireless security domain 11/12/15UB Fall 2015 CSE565: S. Upadhyaya Lec 22.19