[svc]gns3模拟器及探讨几个bgp问题

模拟器

链接：https://pan.baidu.com/s/1geMcmND 密码：7iir
gns0.8.6的版本好用
思科的这个iso好用: c3660-js2-mz.124-21a.bin C2691-AD.BIN(这个也很ok,但是这两个支持的hash算法较少)
ctrl+shit+6 停止命令

R1(config)#crypto isakmp policy 10
R1(config-isakmp)#hash ?
  md5  Message Digest 5
  sha  Secure Hash Standard

cisco ios命名参考
c7200-adventerprisek9-mz.151-4.M2.bin #做证书实验用这个

R1(config)#crypto isakmp policy 10
R1(config-isakmp)#hash ?
  md5     Message Digest 5
  sha     Secure Hash Standard
  sha256  Secure Hash Standard 2 (256 bit)
  sha384  Secure Hash Standard 2 (384 bit)
  sha512  Secure Hash Standard 2 (512 bit)

- 思科ios冷知识

1: RAM：随机访问存储器，相当于计算机的内存
2：ROM：只读存储器，在ROM中驻留了用于启动和维护路由器的一些微代码
3：FLASH: 闪存，相当于计算机的硬盘，存储了IOS文件映像
4：NVRAM: 主要用于存储启动配置文件( Non-Volatile[挥发的] Random Access Memory)
思科路由器不具备存储历史错误记录的能力，只能通过debug进行即时排错。

探讨bgp几个问题

防止环路:
as间 as-path
as内 水平分割
full mesh

更新源的问题
同步问题
ibgp水平分割

• 基础ip配置

R1

conf t
int lo0
ip add 1.1.1.1 255.255.255.255
int f0/0
ip add 12.1.1.1 255.255.255.0
no shu


R2

conf t
int lo0 
ip add 2.2.2.2 255.255.255.255
int f0/0
ip add 12.1.1.2 255.255.255.0
no shu
int f0/1
ip add 23.1.1.2 255.255.255.0
no shu


R3

conf t
int l0
ip add 3.3.3.3 255.255.255.255
int f0/0
ip add 34.1.1.3 255.255.255.0
no shu
int f0/1
ip add 23.1.1.3 255.255.255.0
no shu

R4

conf t
int l0
ip add 4.4.4.4 255.255.255.255
int f0/0
ip add 34.1.1.4 255.255.255.0
no shu

• bgp建立full mesh

R1#s run | s bgp
router bgp 123
 no synchronization
 bgp router-id 1.1.1.1
 bgp log-neighbor-changes
 network 1.1.1.1 mask 255.255.255.255
 neighbor 2.2.2.2 remote-as 123
 neighbor 2.2.2.2 update-source Loopback0
 neighbor 3.3.3.3 remote-as 123
 neighbor 3.3.3.3 update-source Loopback0
 no auto-summary
 
 
R2#s run | s bgp
router bgp 123
 bgp router-id 2.2.2.2
 bgp log-neighbor-changes
 neighbor 1.1.1.1 remote-as 123
 neighbor 1.1.1.1 update-source Loopback0
 neighbor 3.3.3.3 remote-as 123
 neighbor 3.3.3.3 update-source Loopback0

R3#s run | s bgp 
router bgp 123
 bgp router-id 3.3.3.3
 bgp log-neighbor-changes
 neighbor 1.1.1.1 remote-as 123
 neighbor 1.1.1.1 update-source Loopback0
 neighbor 1.1.1.1 next-hop-self
 neighbor 2.2.2.2 remote-as 123
 neighbor 2.2.2.2 update-source Loopback0
 neighbor 2.2.2.2 next-hop-self
 neighbor 34.1.1.4 remote-as 4

R4#s run | s bgp
router bgp 4
 bgp router-id 4.4.4.4
 bgp log-neighbor-changes
 network 4.4.4.4 mask 255.255.255.255
 neighbor 34.1.1.3 remote-as 123