Devops Engineer

ACL: access control list ACL Function: 1. manage the IP  in network 2. filter message when it pass the router ACL Type 1. Standard: Check source address; Allow or reject total protocol 2. Extend: Check source and destination address; Allow or reject special protocol Inbound / Outbound ACL ACL config guide ACL config (config)#access-list <access-list-number> <permit|deny> <test conditions> (config)#<protocol> access-group <access-list-number> <in|out> access-list-number: standard: 1-99 extend: 100-199 IP ACL config At least has one permit access-list Set: (config)#access-list <access-list-number> <permit|deny> source <wildcard mask> access-list-number: 1-99 wildcard mask: default 0.0.0.0(check all bits) Example: for IP 172.16.1.1 --> wildcard mask: 0.0.0.0 for subnet 172.16.1.0 --> wildcard mask: 0.0.0.255 for any network --> wildcard mask: 255.255....

NAT: Network Address Translate Translate the ip address of intranet into that of the internet Private Address: A: 10.0.0.0 B: 172.16.0.0 - 172.31.255.255 C: 192.168.0.0 - 192.168. NAT table Inside Local IP address: IP address of intranet Inside Global IP address: IP address of internet NAT Function 1. Translate the IP address of intranet 2. Use internet IP address for more intranet IP address(divided by ports) Example NAT Type 1. static NAT: manually map between Internet IP address and Intranet IP address. One for one 2. pooled NAT: dynamic map between Internet IP address and Intranet IP address. One for one 3. port NAT(PAT): map between Internet IP address and Intranet IP address. One for more Static NAT config Other IP address of Internet only can ping the outside IP address Pooled NAT (dynamic NAT) config PAT config Verify NAT ...

Cisco ISO: network operation system xxxx-yyy-ww: xxxx: platform (ex, 1005, 1600,3640) yyy: features (ex, n --> IPX; i --> IP subnet) ww: format (ex, f --> flash; m--> RAM; z --> zipped) Cisco: command screen Command mode user mode:      hostname> super mode:    hostname# config mode:  hostname(config)# Switcher signal lights 1. start, all signal lights green 2. port POST successfully, light off; port POST failed, light yellow 3. all ports POST successfully lights off; all ports POST failed lights yellow Switcher startup console information: device information... Go to user mode: press K Go to super mode: enable Go to user mode: quit Switcher check status: show version show running-config show interfaces Config mode Go to config mode: conf term Go to interface config mode: interface e0/1 config hostname: (config)#hostname ...