On the switch，There are three commonly used configuration mode，Respectively Access (Access)，Trunk (trunk or trunk) as well as Hybrid (Hybrid)，These three interfaces operating mode determines the corresponding interface for processing the attitude data packets on the switch。Nowadays，Routing to elaborate on these three models。
Since the switch has divided the virtual LAN VLAN function is，So it[……]
Some time ago I wroteA simple example Cisco routers DHCP and DHCP relay configuration，Article uses a command to achieve theDHCP forwarding，But this function is exactly how to achieve it? Now let's learn more about this command。
When the terminal equipment andDHCP serverWhen not on the same broadcast domain，Intermediate devices need to specify an address to be broadcast packet forwarded out，That needs to be sethelper_add[……]
Today came across configurationDHCP relayThe problem，Suddenly I found that I had actually not noticed，Even sometimes do not know how to engage，And later I had to Google it very awkward ......，Now recorded as follows：
I was not on the map topology，Simple words to describe：
R1(f0/1)————-(f0/1)R2(f0/0)——S1——PC0
[……]
In the study CCNA related courses NAT Network Address Translation content，When the practice often requires no out a dynamic NAT or PAT address pool
Cisco IOS NAT table as long as the provision of translation entries have included the address of the address pool，You will be able to modify or delete the address pool。
at this time，You enter
(config)# no ip nat pool pool_name
[……]