11.2DHCP

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DHCP： Dynamic Host Configuration Protocol – Unified distribution and management IP Address

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be based on UDP agreement , Port number 67&68
be based on Client/Server framework

Become DHCP Server conditions ：
1、 Own legal IP Address
2、 It has its own interface or network card connected to the network range of the address to be issued

DHCP Data package and process ：
client The server
---------DHCP Discover（ radio broadcast ）------------>

<----DHCP Offer（ radio broadcast ）---- // Take what you are going to issue IP Address

---------DHCP Request（ radio broadcast ）------------>

<--------DHCP Ack（ radio broadcast ）------------------

working process ：
Need to get automatically IP The client of the address turns on automatic acquisition IP After the address , Local broadcast is sent DHCP Discover Data packets ,
Source IP Address 0.0.0.0, The goal is IP Address 255.255.255.255, Source MAC The address is the local network card MAC, The goal is MAC by FFFF-FFFF-FFFF,
The source port is 68, The target port is 67;
Open the DHCP After the server of the service receives this packet , Send free ARP To determine what to issue IP There is no address conflict , Then reply in the form of local broadcast DHCP Offer Data packets ,
Source IP Is the server IP Address , The goal is IP Address 255.255.255.255, Source MAC For the server network card MAC, The goal is MAC by FFFF-FFFF-FFFF,
The source port is 67, The target port is 68;
Client side usage DHCP Request Packet request IP Address , Server reply ACK To the client , The client gets IP Address .

Lease term ： The default lease term is 1440min/24h/ One day .
Renewal ： When the lease term arrives 1/2 when , If the client is still online , The client sends out Request Data package to renew ;
If renewal fails , Continue to 7/8 The lease period of is sent again Request Packet renewal ;
If you still fail , The address is taken back when the lease term arrives , If the client wants to continue using , Need to get the address again .

Router as DHCP The server ：
1） Send the address to the global pond
[ ning ]dhcp enable // Opening service
[ ning ]ip pool css // establish DHCP pond , A pond can only serve one network
[ ning -ip-pool-css]network 172.16.1.0 mask 255.255.255.0 // Define the scope of the pond
[ ning -ip-pool-css]gateway-list 172.16.1.1 // configure gateway
[ ning -ip-pool-css]dns-list 114.114.114.114 // To configure DNS

[ ning ]interface GigabitEthernet 0/0/0
[ ning -GigabitEthernet0/0/0]dhcp select global
[ ning -GigabitEthernet0/0/0]dhcp server excluded-ip-address 172.16.1.250 // Exclude an address
[ ning -GigabitEthernet0/0/0]dhcp server static-bind ip-address 172.16.1.111 mac-add
ress aaaa-1122-ab12 // Give a fixed MAC Send a fixed address IP Address

2） With interface IP Address range distribution address
[ ning ]interface GigabitEthernet 0/0/0
[ ning -GigabitEthernet0/0/0]dhcp select interface
[ ning -GigabitEthernet0/0/0]dhcp server dns-list 1.1.1.1 // Set up DNS

ARP： Address resolution protocol , Know each other IP, Request each other MAC
free ARP: Use ARP The technical principle of requests own IP Address of the MAC Address

Dynamic routing

： Some kind of protocol runs between routers （ Algorithm ）, Obtain the unknown path by sending and receiving data packets

The pursuit of dynamic routing protocols ：
1、 Fast convergence
2、 Choose a path
3、 Less occupied resources

Classification of dynamic routing protocols ：
1、 be based on AS The classification of ：
AS–Autonoumous System, Autonomous systems . Use numbering to indicate , Range 0-65535, among 0-64511 by
public AS Number ,64512-65535 private AS Number

IGP（ Internal gateway protocol ） agreement –AS Protocol running within ：RIP、OSPF、EIGRP-Cisco private 、ISIS
EGP（ External gateway protocol ） agreement –AS Agreement running between ：BGP

2、IGP Classification of protocols ：
DV type - Distance vector ：RIP、EIGRP– Shared routing table
LS type - Link state ：OSPF、ISIS– Shared topology

RIP：Routing Information Protocol, Routing information protocol
1） Basic concepts
edition ：RIPv1 RIPv2 RIPng（IPV6）
The standard DV Type Routing Protocol – Shared routing table
be based on UDP agreement , Port number 520
Update the way ： Cycle update （30s）– confirm 、 Keep alive
RIP priority 100 Use hops as a measure

2）RIPv1 and RIPv2 The difference between
1、RIPv1 Bisect – The same route entry , From this mouth into not from this mouth again . Used to eliminate duplicate updates .
Only the loop of linear topology and star topology can be eliminated

2、 toxicity   Reverse horizontal segmentation -- Core ring breaking mechanism 

4）RIP Configuration of
No matter which version RIP, When declaring, use the main class scope
1、RIPv1 Configuration of
[ ning ]rip 1 // Boot protocol , You need to configure the process number
[r1-rip-1]version 1 // Choose the version , Must choose
Declare ：1、 Activate interface 2、 Publish route
[ ning -rip-1]network 1.0.0.0
[ ning -rip-1]network 12.0.0.0 Update without mask ,RIPv2 Carry mask when updating
2、RIPv1 Broadcast updates ,RIPv2 Multicast update –224.0.0.9
3、RIPv2 Support manual authentication – Identity verification between neighbors

3）RIP Data packets –update package , Carried routing entries

4）RIP Ring breaking mechanism
1、 water
2、RIPv2 Configuration of

5）RIP Extended configuration for
1、 Summary
[ ning ]interface GigabitEthernet 0/0/0 // Update the interface sent
[ ning -GigabitEthernet0/0/0]rip summary-address 1.0.0.0 255.252.0.0
2、 Default route - On the border router connecting the operator

[r ning  ]rip 1	
[ ning -rip-1]default-route originate 

3、 Silent interface -- Only receive, not send RIP Data packets . It is generally used to connect the interface of users , It is forbidden to use it for the interface between routers 
[ ning ]rip 1
[ ning -rip-1]silent-interface GigabitEthernet 0/0/1