Daily/networking/cisco/cisco-asa.md

CISCO ASA 5505

ciscoasa# show version

factory defaults

? configure factory-default confreg 0x2040 relo

disable call-home function

Enable Management Access with ASDM ASA(config)# asdm image disk0:/asdm-647.bin [Location of ASDM image on the ASA] ASA(config)# http server enable [Enable the http server on the device ] ASA(config)# http 10.10.10.0 255.255.255.0 inside [Tell the device which IP addresses are allowed to connect with HTTP (ASDM)] ASA(config)#username admin password adminpass [Configure user/pass to login with ASDM]

DHCP

DHCP (Assign IP addresses to computers from the ASA device) ciscoasa(config)# dhcpd address 192.168.1.101-192.168.1.110 inside [Create a DHCP address pool to assign to clients. This address pool must be on the same subnet as the ASA interface] ciscoasa(config)# dhcpd dns 209.165.201.2 209.165.202.129 [The DNS servers to assign to clients via DHCP] ciscoasa(config)# dhcpd enable inside [Enable the DHCP server on the inside interface]

Permit Traffic Between Same Security Levels ciscoasa(config)# same-security-traffic permit inter-interface [Permits communication between different interfaces that have the same security level.] ciscoasa(config)# same-security-traffic permit intra-interface [Permits traffic to enter and exit the same interface.]

Useful Verification and Troubleshooting Commands ciscoasa# show access-list OUTSIDE-IN [Shows hit-counts on ACL with name “OUTSIDE-IN”. It shows how many hits each entry has on the ACL]

Sample output:
access-list OUTSIDE-IN line 1 extended permit tcp 100.100.100.0 255.255.255.0 10.10.10.0 255.255.255.0 eq telnet (hitcnt=15) 0xca10ca21

ciscoasa# show conn [The show conn command displays the number of active TCP and UDP connections, and provides information about connections of various types.] ciscoasa# show conn all [Shows all the connections through the appliance] ciscoasa# show conn state up,http_get,h323,sip [Shows HTTP GET, H323, and SIP connections that are in the “up” state] ciscoasa# show conn count 54 in use, 123 most used [Shows overall connection counts]

ciscoasa# show cpu usage [show CPU utilization] ciscoasa# show disk [List the contents of the internal flash disk of the ASA] ciscoasa# show environment [Displays operating information about hardware system components such as CPU, fans, power supply, temperature etc] ciscoasa# show memory [Displays maximum physical memory and current free memory]

ciscoasa# show failover [Displays information about Active/Standby failover status] ciscoasa# show interface [Shows information about Interfaces, such as line status, packets received/sent, IP address etc] ciscoasa# show local-host [Displays the network states of local hosts. A local-host is created for any host that forwards traffic to, or through, the ASA.]

ciscoasa# show route [Displays the routing table]

ciscoasa# show xlate [Displays information about NAT sessions]

reset password

on console, during boot, hit ESC, enter ROMMON mode

confreg 0x41 boot

after reboot, password is empty, set enable's password

(very strong password, use different admin user to process changes)

enable password (password)

enter config mode

enable configure terminal

show configs

ciscoasa# show startup-config ciscoasa# show running-config

set hostname, print label, attach to device

hostname (hostname)

set clock

ciscoasa# show clock ciscoasa# clock set 07:29:00 May 06 2019 ciscoasa(config)# clock timezone UTC +3

if DST presents

ciscoasa(config)# clock summer-time MST recurring 1 Sunday April 2:00 last Sunday October 2:00

enable logging

ASA(config)# logging enable ASA(config)# logging timestamp ASA(config)# logging buffer-size 65536 ASA(config)# logging buffered warnings ASA(config)# logging asdm errors

send to syslog, if needed

ASA(config)# logging host inside 192.168.1.30 ASA(config)# logging trap errors

save configs to memory

ciscoasa# copy run start Source filename [running-config] ?

[enter] to confirm

or (will not ask source)

ciscoasa# write memory

add user

username (username) nopassword username (username) password (password)

permit local aaa

hostname(config)# aaa authorization exec authentication-server

list users

change password of user

delete user

give user privileges

username (username) password (password) privilege 15 username (username) attributes ciscoasa(config-username)# service-type admin ciscoasa(config-username)# service-type nas-prompt ciscoasa(config-username)# service-type remote-access ciscoasa(config-username)# exit

add SSH access

ASA#configure terminal ASA(config)#domain-name local.local

 ASA(config)#aaa authentication ssh console LOCAL

ciscoasa(config)#aaa authentication ssh console LOCAL

             aaa authentication ssh console LOCAL

crypto key generate rsa modulus 2048

  ASA(config)#crypto key generate rsa general-keys modulus 1024
              crypto key generate rsa modulus modulus_size

ciscoasa(config)# crypto key generate rsa modulus 2048 ASA(config)#ssh 192.168.1.10 255.255.255.255 inside ASA(config)#ssh 0.0.0.0 0.0.0.0 OUTSIDE

verify which encryptions are enabled

show ssh

connect via ssh (some routers use (old) SSH1)

download file (firmware, config) from device

Image Software Management ciscoasa# copy tftp flash [Copy image file from TFTP to Flash of ASA] ciscoasa#config term ciscoasa(config)# boot system flash:/asa911-k8.bin [At next reboot, the firewall will use the software image “asa911-k8.bin” from flash]

upload file

copy file to USB

copy file from USB

upgrade firmware

show interfaces

show interface ip brief show switch vlan

set up interfaces (example: outside-inside)

ciscoasa(config)# interface Vlan 10 ciscoasa(config-if)# nameif outside ciscoasa(config-if)# security-level 80 ciscoasa(config-if)# ip address 192.168.100.77 255.225.255.0 ciscoasa(config-if)# no shutdown ciscoasa(config-if)# exit

ciscoasa(config)# interface Vlan 20 ciscoasa(config-if)# nameif lab5 ciscoasa(config-if)# security-level 90 ciscoasa(config-if)# ip address 192.168.2.1 255.225.255.0 ciscoasa(config-if)# no shutdown ciscoasa(config-if)# exit

ciscoasa(config)# interface Ethernet 0/0 ciscoasa(config-if)# no nameif ciscoasa(config-if)# no security-level ciscoasa(config-if)# no ip address ciscoasa(config-if)# switchport access 10 ciscoasa(config-if)# no shutdown ciscoasa(config-if)# exit

(same for 0/6 PoE, deskphone)

ciscoasa(config)# interface Ethernet 0/6

to check PoE status

show power inline

ciscoasa(config)# interface Ethernet 0/1 ciscoasa(config-if)# no nameif ciscoasa(config-if)# no security-level ciscoasa(config-if)# no ip address ciscoasa(config-if)# switchport access 20 ciscoasa(config-if)# no shutdown ciscoasa(config-if)# exit

routing (traffic to modem of ISP)

ciscoasa(config-if)# route outside 0.0.0.0 0.0.0.0 192.168.100.1 1

same level security traffic

hostname(config)# same-security-traffic permit inter-interface

set up VPN

ciscoasa# show crypto ipsec sa [show details about IPSEC VPNs like packets encrypted/decrypted, tunnel peers etc] ciscoasa# show crypto isakmp sa [show details if an IPSEC VPN tunnel is up or not. MM_ACTIVE means the tunnel is up]

The absolutely necessary Interface Sub-commands that you need to configure in order for the interface to pass traffic are the following:

nameif “interface name”: Assigns a name to an interface
ip address “ip_address” “subnet_mask” : Assigns an IP address to the interface
security-level “number 0 to 100” : Assigns a security level to the interface
no shutdown : By default all interfaces are shut down, so enable them.

Static and Default Routes ciscoasa(config)# route outside 0.0.0.0 0.0.0.0 100.1.1.1 MORE READING: Cisco ASA Firewall in Transparent Layer2 Mode [Configure a default route via the “outside” interface with gateway IP of 100.1.1.1 ]

ciscoasa(config)# route inside 192.168.2.0 255.255.255.0 192.168.1.1 [Configure a static route via the “inside” interface. To reach network 192.168.2.0/24 go via gateway IP 192.168.1.1 ]

Network Address Translation (NAT) ciscoasa(config)# object network internal_lan ciscoasa(config-network-object)# subnet 192.168.1.0 255.255.255.0 ciscoasa(config-network-object)# nat (inside,outside) dynamic interface [Configure PAT for internal LAN (192.168.1.0/24) to access the Internet using the outside interface]

ciscoasa(config)# object network obj_any ciscoasa(config-network-object)# subnet 0.0.0.0 0.0.0.0 ciscoasa(config-network-object)# nat (any,outside) dynamic interface [Configure PAT for all (“any”) networks to access the Internet using the outside interface]

ciscoasa(config)# object network web_server_static ciscoasa(config-network-object)# host 192.168.1.1 ciscoasa(config-network-object)# nat (DMZ , outside) static 100.1.1.1 [Configure static NAT. The private IP 192.168.1.1 in DMZ will be mapped statically to public IP 100.1.1.1 in outside zone]

ciscoasa(config)# object network web_server_static ciscoasa(config-network-object)# host 192.168.1.1 ciscoasa(config-network-object)# nat (DMZ , outside) static 100.1.1.1 service tcp 80 80 [Configure static Port NAT. The private IP 192.168.1.1 in DMZ will be mapped statically to public IP 100.1.1.1 in outside zone only for port 80]

FIREWALL Access Control Lists (ACL)

show

show run access-list (host) show access-list (host)

[Apply the ACL above at the “outside” interface for traffic coming “in” the interface] ciscoasa(config)# access-group OUTSIDE_IN in interface outside ciscoasa(config)# access-group INSIDE_IN in interface inside

[Create an ACL to allow TCP access from “any” source IP to host 192.168.1.1 port 80] ciscoasa(config)# access-list OUTSIDE_IN extended permit tcp any host 192.168.1.1 eq 80

[Create an ACL to deny all traffic from host 192.168.1.1 to any destination and allow everything else. This ACL is then applied at the “inside” interface for traffic coming “in” the interface] ciscoasa(config)# access-list INSIDE_IN extended deny ip host 192.168.1.1 any ciscoasa(config)# access-list INSIDE_IN extended permit ip any any

Object Groups

ciscoasa(config)# object-group network WEB_SRV ciscoasa(config-network)# network-object host 192.168.1.1 ciscoasa(config-network)# network-object host 192.168.1.2 [Create a network group having two hosts (192.168.1.1 and 192.168.1.2). This group can be used in other configuration commands such as ACLs]

ciscoasa(config)# object-group network DMZ_SUBNETS ciscoasa(config-network)# network-object 10.1.1.0 255.255.255.0 ciscoasa(config-network)# network-object 10.2.2.0 255.255.255.0 [Create a network group having two subnets (10.1.1.0/24 and 10.2.2.0/24). This group can be used in other configuration commands such as ACLs]

ciscoasa(config)# object-group service DMZ_SERVICES tcp ciscoasa(config-service)# port-object eq http ciscoasa(config-service)# port-object eq https ciscoasa(config-service)# port-object range 21 23 [Create a service group having several ports. This group can be used in other configuration commands such as ACLs]

ciscoasa(config)# access-list OUTSIDE-IN extended permit tcp any object-group DMZ_SUBNETS object-group DMZ_SERVICES [Example of using object groups in ACLs]

# create group
(config)# object-group network (hostgroup)

# add object into group
(config-network-object-group)# network-object object (newhost)

# show objects
show object-group network
exit

# edit objects
object network (newhost)
host (ip)

CISCO FIREWALL:

enable SSH

https://www.opentechguides.com/how-to/article/cisco/39/Cisco-configure-ssh.html

LOGIN

enable pass again

CONFIGURE MODE

configure terminal

CHECKING EXISTING

show running-config | include (ip-from) show running-config | include (ip-to) show access-list outside_in show run | include (ip) show (ip)

interfaces

show interfaces status

edit in editor, paste

configure terminal

access-groups

show configuration | include access-group ip access-group access-list-name {in | out} no ip access-group access-list-name {in | out}

let host out:

access-list (zone) extended permit udp host (ip) host (ip) eq (port) access-list (zone) extended permit tcp host (ip) host (ip) eq (port) access-list (zone) extended permit tcp any4 host (ip) eq https

write configuration

wr (copy running-config startup-config) wr write mem

capturing

capture capin interface outside match tcp host (host) host (host) eq (port) show capture show capture capin

general commands

show run | include route

enable unsupported tranceiver

service unsupported-transceiver no errdisable detect cause gbic-invalid

trunk port

show interfaces trunk (config-if)#interface gigabitEthernet 0/23 (config-if)#description Trunk port to (host) (config-if)#switchport mode trunk (config-if)#switchport trunk allowed vlan all (config-if)#switchport trunk allowed vlan 2-4094 no shutdown

access port

(config)#interface gigabitEthernet 0/23 (config-if)#description (host) (config-if)#switchport mode access (config-if)#switchport access vlan 128 (config-if)#no shutdown

save (commit)

write mem

sources:

https://www.cisco.com/c/en/us/td/docs/security/asa/asa82/configuration/guide/config.html https://www.cisco.com/c/en/us/td/docs/security/asa/asa82/configuration/guide/config/access_aaa.html

https://www.cisco.com/c/en/us/td/docs/security/asa/asa92/configuration/general/asa-general-cli/interface-basic-5505.pdf https://www.cisco.com/c/en/us/td/docs/security/asa/asa91/configuration/general/asa_91_general_config/route_static.pdf