DNS, DHCP, SNMP & Network Security

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IP AddressResolutionroot NSLecture 12NS: Name Servercom NSjp NSfoobar NScandy NSwww.hosei.ac.jp 133.25.252.22 Step 3Cache table:R R R Rhttp://www.hosei.ac.jp judy http://133.25.252.22:80www.hosei.ac.jp 133.25.252.22Step 1Step 2133.25.252.22ac NShosei NSwww.hosei.ac.jpwwwDNS DBwww.hosei.ac.jp133.25.252.22…………….www.hosei.ac.jp 133.25.252.22• DNS request is forwarded to root server, which points at next server to use• Eventually, authoritative server is located and IP address is returned• DNS server hierarchy traversal is called iterative resolution• Servers and hosts use caching to reduce the number of DNS requests• Each domain may keep many NS copies to speedup address resolutionmore than 13 root servers distributed all around the world• DNS Types: A, NS, MX (Mail Exchange), SOA (Start OF Authority), CNAME (Canonical Name)• nslookup utility: >domain_name or IP address, >set querytype=NS, A, …A Video demo at http://www.youtube.com/watch?v=2ZUxoi7YNgs
Lecture 12Computer Booting and Configuration• Booting or Bootstrapping- Software system/network initialization process when computer turned on• Protocol software needs specific information for operation• Software employs parameters for operation on a specific hardware and network• ConfigurationProcess of supplying parameters to protocol software‣IP address - depends on network, must be unique on network‣Default router address - where to send packets aimed at remote network‣Subnet mask - to specify if subnet addressing is used and what the subnet is‣DNS server address - for DNS queries‣Other Server addresses – printerStatic (no change) and dynamic (change each time) parametersManual configuration- sets and saves parameters in local diskAutomated configuration- Gets parameters from another computer connected the same network- Previous technique is BOOTP (Bootstrap Protocol)- Current technique is DHCP (Dynamic Host Configuration Protocol)- Uses UDP for parameter transfer. How to transfer when unknowing parameters?
Page 1 and 2: Lecture 12DNS, DHCP, SNMP & Network
Page 3 and 4: Address ResolutionLecture 12DNSRARP
Page 5: DNS Server HierarchyLecture 12DN: D
Page 9 and 10: Lecture 12DHCP Messages for Getting
Page 11 and 12: DHCP Messaging ExampleDHCPDHCPDHCPD
Page 13 and 14: Lecture 12DHCPMessage Format• Ope
Page 15 and 16: Lecture 12NAT Working Mechanismrest
Page 17 and 18: Lecture 12Network Management• Res
Page 19 and 20: Management data transferbetween man
Page 21 and 22: Identify MIB ObjectrootLecture 12Hi
Page 23 and 24: Lecture 12SNMP Operations and Messa
Page 25 and 26: Secure Key EncryptionLecture 12Mess
Page 27 and 28: Lecture 12Authentication and Confid
Page 29: Exercise 121. Using nslookup utilit

DNS, DHCP, SNMP & Network Security

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