Credit to the original author @grplyler
Expanded upon by @MrPenguin07
Added new sections
- Syslog, Restore firmware, Rollback with
revert - BGP, OSPF, Added Cisco-send
- Spanning-tree, SPAN, TFTP, DHCP
ip helper-address - Diagnosing issues, Useful cmds, ZBF
To-Do
- ACLs
- Device auth.
- RIPv2
- GRE/IPSEC
- HSRP/GLBP
- SNMP
- VOIP
- NAT
- Static routing
- Basic Networking
- Intermediate Networking
- Advanced Networking
- Monitoring/Logging
- Useful Commands
- Diagnostics
- How To's
- Tools
- Intermediate Networking
- Advanced Networking
- Useful Commands
- Diagnostics
- How To's
These commands wipe all config and reboot the device
erase startup-config
delete vlan.dat
reload
Note: Remember to say "no" to saving running config on reload. If you say yes, running config will be saved and you wont be working with fresh config on reload.
configure terminal
no ip domain-lookup
hostname S1
line console 0
logging synchronous
exit
banner motd $ Authorized Access Only! And Godzilla will beat Kong any day $
exit
copy running-config startup-config
configure terminal
no ip domain-lookup
hostname R1
line console 0
logging synchronous
exit
banner motd $ Authorized Access Only! And Godzilla will beat Kong any day $
exit
copy running-config startup-config
configure terminal
no ip domain-lookup
hostname R1
line console 0
logging synchronous
exit
banner motd $ Authorized Access Only! And Godzilla will beat Kong any day $
exit
copy running-config startup-config
conf t
enable secret class
line console 0
password cisco
login
exit
line vty 0 4
password cisco
login
exit
service password-encryption
end
copy running-config startup-config
conf t
enable secret class
line console 0
password cisco
login
exit
line vty 0 4
password cisco
login
exit
service password-encryption
end
show ip ssh
conf t
ip domain-name cisco.com
crypto key generate rsa
username admin secret ccna
line vty 0 15
transport input ssh
login local
exit
ip ssh version 2
exit
Show Clock
show clock
Sets clock to eastern US time
clock timezone EST -5
Revert to Default Timezone
no clock timezone
conf t
! Logout timer
!
line con 0
exec-timeout 5
line vty 0 4
exec-timeout 5
exit
ip ssh time-out 60
ip ssh authentication-retries 3
end
Using included FTP server
copy running-config startup-config
copy startup-config ftp://192.168.1.10/config.txt
A simple yet effective method here is to;
set terminal length 0
show run
Highlight and copy paste to local machine. Perhaps set terminal length back to ~25 so the less pager works again.
copy ftp://192.168.1.10/config.txt running-config
Assign an IP address to a port
conf t
int f0/1
ip addr 192.168.10.11 255.255.255.0
end
cont t
int g0/0
ip addr 10.0.0.10 255.255.255.0
Assign and IP address to a port
conf t
int f0/1
ip addr 192.168.10.11 255.255.255.0
end
Select Single Range and Assign to a VLAN
conf t
int range f0/1-12
switchport mode access
switch access vlan 10
end
conf t
int range f0/13-24
switchport mode access
switchport access vlan 20
end
Select Multiple Interface Ranges and Move to a VLAN
conf t
int range f0/1-4,g0/1,f0/16-20
switchport mode access
switchport access vlan 10
end
show ip interface brief
or
show ip int br
conf t
int f0/1
no ip addr
end
conf t
line con 0
speed 115200
end
conf t
line con 0
speed 9600
end
This snippet configures a DHCP Server on R1 and will hand out
IPs on the 10.0.0.1/24 network. Great for using an FTP Server with.
conf t
ip domain name cisco.com
ip dhcp excluded-address 10.0.0.1
ip dhcp pool test
network 10.0.0.0 255.255.255.0
default-router 10.0.0.1
end
ip dhcp pool test
network 10.0.0.0 255.255.255.0
domain-name cisco.com
default-router 10.0.0.1
dns-server 10.0.0.1
lease 4
ip dhcp snooping
ip dhcp-server 10.0.0.3
interface vlan 1
ip address 10.0.0.3
Workaround for CCNA labs at Liberty University since we can't change the LAB IP addresses
conf t
ip domain name cisco.com
ip dhcp excluded-address 10.0.0.1
ip dhcp pool managementpool
network 10.0.0.1 255.255.255.0
default-router 10.0.0.1
end
conf t
ip dhcp excluded-address 192.168.10.1
ip dhcp excluded-address 192.168.10.254
ip dhcp pool office-pool-1
network 192.168.10.0 255.255.255.0
default-router 192.168.10.1
dns-server 192.168.5.5
domain-name linux.org
end
# show running-config | section dhcp
# show ip dhcp binding
# show ip dhcp server statistics
The ip helper-address command is used on a router's interface to enable forwarding of DHCP broadcasts onto other networks.
It allows clients on a subnet without a DHCP server to reach the DHCP server on another subnet.
conf t
# interface <interface_type> <interface_number>
# ip helper-address <dhcp_server_ip>
Configure the IP helper-address on the interface that receives the DHCP requests, specifying the IP address of the DHCP server.
# show ip interface <interface_type> <interface_number>
This command checks the configuration of the ip helper-address on a specific interface to ensure it's correctly set to the DHCP server's IP address.
conf t
no service dhcp
end
conf t
service dhcp
end
Creates a Seperate DHCP Pool for each VLAN
Create VLANS
conf t
vlan 10
name Management
vlan 20
name Sales
vlan 30
name Operations
end
Configure SVI's and IP Address
| VLAN | IP Address | Gateway |
|---|---|---|
| 10 | 192.168.10.254 | 192.168.10.1 |
| 20 | 192.168.20.254 | 192.168.20.1 |
| 30 | 192.168.30.254 | 192.168.30.1 |
conf t
int vlan 10
ip address 192.168.10.254 255.255.255.0
ip default-gateway 192.168.10.1
no shut
int vlan 20
ip address 192.168.20.254 255.255.255.0
ip default-gateway 192.168.20.1
no shut
int vlan 30
ip address 192.168.30.254 255.255.255.0
ip default-gateway 192.168.30.1
no shut
end
Add interfaces to VLANS, 8 ports per vlan
conf t
int range f0/1-7
switchport mode access
switchport access vlan 10
int range f0/8-15
switchport mode access
switchport access vlan 20
int range f0/16-24
switchport mode access
switchport access vlan 30
end
Create DHCP Pools for each vlan
conf t
ip domain name cisco.com
ip dhcp excluded-address 192.168.10.1
ip dhcp pool vlan10pool
network 192.168.10.0 255.255.255.0
default-router 192.168.10.1
import all
ip dhcp excluded-address 192.168.20.1
ip dhcp pool vlan20pool
network 192.168.20.0 255.255.255.0
default-router 192.168.20.1
import all
ip dhcp excluded-address 192.168.30.1
ip dhcp pool vlan30pool
network 192.168.30.0 255.255.255.0
default-router 192.168.30.1
import all
end
Now when a device plugs into a port f0/4 for instance and performs a DHCP request, it should get an IP like 192.168.10.3 because it is plugged into the ports assigned to VLAN 10
show ip dhcp pool
conf t
no ip dhcp pool managementpool
end
conf t
vlan 10
name Faculty
exit
conf t
vlan 20
name Students
exit
conf t
interface range Fa0/1-12
switchport mode access
switchport access vlan 10
end
conf t interface range Fa0/13-24
switchport mode access
switchport access vlan 20
end
conf t
interface Gi0/1
switchport mode access
switchport access vlan 99
end
cont t
int vlan 99
ip address 10.0.0.1 255.255.255.0
end
show vlan brief
Assuming Data on VLAN 10, Voice on VLAN 20
conf t
int Fa0/4
switchport mode access
switchport access vlan 10
switchport voice vlan 20
end
conf t
vlan 99
name Management
exit
interface Fa0/24
switchport mode access
switchport access vlan 99
exit
int vlan 99
ip addr 10.0.0.1 255.255.255.0
end
delete vlan.dat
Warning: Make sure you move ports to another vlan or the will be unsable
conf t
no vlan 10
no vlan 20
end
Creates multiple sub-interfaces on a router port to enable inter-vlan routing.
Note: encapsulation dot1q must be called on a sub interface before an IP can be assigned to it.
conf t
interface G0/0/1.10
description Default Gateway for VLAN 10
encapsulation dot1Q 10
ip add 192.168.10.1 255.255.255.0
exit
interface G0/0/1.20
description Default Gateway for VLAN 20
encapsulation dot1Q 20
ip addr 192.168.20.1 255.255.255.0
exit
interface G0/0/1.99
description Default Gateway for VLAN 99
encapsulation dot1Q 99
ip addr 192.168.99.1 255.255.255.0
exit
interface G0/0/1
description Trunk link to S1
no shut
end
S1
conf t
interface Gi0/1
description Trunk Line to S2 Gi0/1
switchport mode trunk
switchport trunk native vlan 99
switchport trunk allowed vlan 99
end
Note: Remember to set the native vlan (to 99 for instance) on each switch in the trunk so you don't get a native vlan mismatch warning
show interface trunk
show interface g0/1 switchport
Etherchannel protocols LACP and PAgP configure multiple physical interfaces and links to act as one logical one. You can configure up to 8 ports to act as a single link. This increases bandwidth and improves redundancy.
Note: mode active sets the etherchannel group to use the LACP protocol
Configure etherchannel between two switches connected with two ethernet cables.
conf t
int range f0/1-2
channel-group 1 mode active
exit
int port-channel 1
switchport mode trunk
switchport trunk allowed vlan 1,2,20
show interfaces trunk
show etherchannel summary
conf t
int gi0/1
switchport mode dynamic auto
end
or
conf t
int gi0/1
switchport mode dynamic desirable
end
Usefull for connecting to devices that don't support Cisco propietary DTP or creating a static trunk
conf t
int gi0/1
switchport mode trunk
switchport nonegotiate
end
show dtp interface gi0/1
conf t
spanning-tree vlan <vlan_id>
Where <vlan_id> is the VLAN ID for which STP is being configured.
spanning-tree mode { pvst | rapid-pvst | mst }
Choose pvst for Per-VLAN Spanning Tree, rapid-pvst for Rapid Per-VLAN Spanning Tree, or mst for Multiple Spanning Tree.
spanning-tree vlan <vlan_id> priority <priority_value>
Where <vlan_id> is the VLAN ID, and <priority_value> is the priority value (0, 4096, 8192, 12288, ..., 61440).
spanning-tree vlan 1-4094 priority <priority_value>
spanning-tree vlan <vlan_id> root {primary|secondary}
This command configures the current switch as the root bridge for the specified VLAN.
show spanning-tree
show spanning-tree vlan <vlan_id>
show spanning-tree interface <interface_type> <interface_number> detail
Zone-Based Firewalls in Cisco IOS are advanced security features that allow you to create different security zones in your network and apply specific policies to control the traffic flow between these zones.
conf t
# zone security <zone_name>
This command is used to define a security zone. Each zone represents a segment of your network. Replace <zone_name> with a descriptive name for the zone.
class-map type inspect match-any <class_map_name>
match protocol <protocol>
Class maps are used to classify traffic based on specific criteria. The match protocol command allows you to specify which protocol you want to match, like HTTP, FTP, or others.
To view the list of protocols available for inspection, you can use the show policy-map type inspect protocol command. This command will list all protocols that the firewall can inspect.
policy-map type inspect <policy_map_name>
class type inspect <class_map_name>
inspect
Policy maps are where you define the actions to be taken on the traffic classified by the class maps. The inspect action, for example, enables stateful inspection of the traffic.
This stateful inspection allows the firewall to keep track of active sessions and make decisions based on the state of these sessions.
zone-pair security <zone_pair_name> source <source_zone> destination <destination_zone>
service-policy type inspect <policy_map_name>
After defining your class maps and policy maps, you need to apply them to a zone pair. This command specifies the source and destination zones and applies the policy map to control traffic between these zones.
conf t
# interface <interface_type> <interface_number>
zone-member security <zone_name>
This command is used to assign an interface on your device to a specific security zone, effectively placing that interface within the defined security context.
# show zone security
# show policy-map type inspect zone-pair sessions
Use these commands to verify your configuration. The first command shows the defined security zones, while the second displays active sessions based on your policy maps.
show ip ospf neighbor
show ip ospf database
Starting Mode: Global, Non-enabled
enable
conf t
router ospf 10
enable
conf t
interface Loopback 1
ip addr 1.1.1.1 255.255.255.255
end
replace 1.1.1.1 with desired id
conf t
router ospf 10
router-id 1.1.1.1
end
Prompt confirmation with 'y' needed
conf t
router ospf 10
router-id 1.1.1.2
end
clear ip ospf process
Verify
show ip proto | include Router ID
Router(config-router)# network network-address wildcard-mask area area-id
The following configures a trianngle of 3 routers connected to each other as an OSPF point to point network.
conf t
router ospf 10
network 10.10.1.0 0.0.0.255 area 0
network 10.10.1.4 0.0.0.3 area 0
network 10.10.1.12 0.0.0.3 area 0
end
conf t
router ospf 10
network 10.10.1.1 0.0.0.0 area 0
network 10.10.1.5 0.0.0.0 area 0
network 10.10.1.14 0.0.0.0 area 0
end
Configure OSPF directly on the interfaces rather with with the network command.
Syntax: Router(config-if)# ip ospf <process-id> area <area-id>
R1(config)# router ospf 10
R1(config-router)# no network 10.10.1.1 0.0.0.0 area 0
R1(config-router)# no network 10.1.1.5 0.0.0.0 area 0
R1(config-router)# no network 10.1.1.14 0.0.0.0 area 0
R1(config-router)# interface GigabitEthernet 0/0/0
R1(config-if)# ip ospf 10 area 0
R1(config-if)# interface GigabitEthernet 0/0/1
R1(config-if)# ip ospf 10 area 0
R1(config-if)# interface Loopback 0
R1(config-if)# ip ospf 10 area 0
R1(config-if)#
conf t
router ospf 10
passive-interface loopback 0
end
conf t
router ospf 10
passive-interface Gi0/0/0
end
show ip ospf interface GigabitEthernet 0/0/0
conf t
interface GigabitEthernet 0/0/0
ip ospf network point-to-point
Loobacks can be used to simulate real LAN networks
conf t
interface Loopback 0
ip ospf network point-to-point
show ip route | include 10.10.1
conf t
int g0/0/1
ip ospf priority 255
end
Where 255 can be values from 0 to 255 with higher numbers making the router to be elected DR.
Router# router ospf 10
Router(config-router) auto-cost reference bandwidth 1000
Where 1000 is the speed of the link in Mpbs Common Values: 10, 100, 1000
conf t
int g0/0/1
ip ospf cost 25
interface l0
ip ospf cost 15
end
show ip ospf int g0/0/1
Router(config-if)# ip ospf hello-interval <seconds>
conf t
int g0/0/1
ip ospf hello-interval 30
end
Note: dead-interval automatically gets set as hello-interval * 4
conf t
ip route 0.0.0.0 0.0.0.0 loopback 1
router ospf 10
default-information originate
show ip route | begin Gateway
show ip ospf neighbor
show ip protocols
show ip ospf
show ip ospf int g0/0/1
show ip ospf int brief
Where g0/0/1 is the interface you was to see OSPF information on.
conf t
int g0/0/1
ip ospf dead-interval 100
end
conf t
router bgp <AS_number>
bgp router-id <router_id>
Where <AS_number> is the Autonomous System number for the router and <router_id> is the desired router ID, typically formatted as an IP address.
conf t
router bgp <AS_number>
neighbor <neighbor_IP> remote-as <remote_AS_number>
Where <neighbor_IP> is the IP address of the BGP neighbor and <remote_AS_number> is the Autonomous System number of the BGP neighbor.
show ip bgp summary
show ip bgp
conf t
router bgp <AS_number>
network <network_address> mask <subnet_mask>
Where <network_address> is the network you want to advertise and <subnet_mask> is the subnet mask for the network.
conf t
router bgp <AS_number>
aggregate-address <aggregate_address> <aggregate_mask>
Where <aggregate_address> is the summarized network address and <aggregate_mask> is the subnet mask for the summarized network.
conf t
router bgp <AS_number>
redistribute static
Where <AS_number> is the Autonomous System number for the router.
conf t
router bgp <AS_number>
redistribute ospf <process_id>
Where <AS_number> is the Autonomous System number for the router, and <process_id> is the OSPF process ID.
conf t
router bgp <AS_number>
redistribute connected
Where <AS_number> is the Autonomous System number for the router.
show ip bgp
Create a SPAN session to monitor traffic:
conf t
monitor session <session_number> source interface <interface_type> <interface_number>
monitor session <session_number> destination interface <interface_type> <interface_number>
Can monitor a port/range, a VLAN or range of VLANs etc.
Create an RSPAN VLAN, then configure the source and destination sessions:
conf t
vlan <vlan_id>
remote-span
exit
monitor session <session_number> source remote vlan <vlan_id>
monitor session <session_number> destination interface <interface_type> <interface_number>
show monitor session <session_number>
Set the address of the Syslog server and enable logging:
conf t
logging host <syslog_server_ip>
logging on
Where <syslog_server_ip> is the IP address of your Syslog server.
conf t
logging trap <level>
Where can be one of the following: emergencies, alerts, critical, errors, warnings, notifications, informational, debugging.
show logging
Pipes ( | ) in Cisco IOS are used to filter the output of commands, making it easier to find specific information.
<command> | include <expression>
Filters the output to only show lines that include the specified expression.
<command> | exclude <expression>
Filters the output to remove lines that contain the specified expression.
<command> | section <expression>
Displays the output section that includes the specified expression. Particularly useful for commands that have a structured output like show running-config.
<command> | begin <expression>
Displays the output starting from the line where the specified expression first appears, which is useful for quickly navigating to a specific part of the command output.
conf t
# line con 0
# logging synchronous
This command prevents console messages from interrupting command input by synchronizing log messages.
conf t
no ip domain-lookup
Disables DNS lookup to prevent the router from attempting to translate incorrectly entered commands as domain names.
conf t
banner motd # [Your Message Here] #
Sets a message-of-the-day banner that appears on all connected terminals. Replace [Your Message Here] with your desired text.
conf t
alias exec [shortcut] [command]
Creates a shortcut (alias) for a longer command. Replace [shortcut] with your alias and [command] with the command it represents.
conf t
no service tcp-small-servers
no service udp-small-servers
Disables TCP and UDP small servers, which are often unnecessary and can be a security risk.
conf t
interface [interface_type] [interface_number]
description [text]
Adds a description to an interface. Replace [interface_type] and [interface_number] with the specific interface details and [text] with the description.
# show processes cpu
# show processes memory
Displays information about the router's CPU/mem processes and their utilization.
# terminal monitor
Enables the display of log and debug command output on your terminal. Useful in SSH or Telnet sessions.
# show ip bgp summary
This command provides a snapshot of the BGP routing process, displaying the number of BGP routes and the status of BGP peers.
Example output includes a list of BGP neighbors, the AS number, the last time the BGP peer was up, and the state of the BGP session (e.g., Established).
# show ip bgp neighbors
Use this command to get detailed information about each BGP neighbor, such as BGP state, configured timers, and counters for messages sent and received.
The output will give you insights into the BGP session's performance and help identify any configuration mismatches between neighbors.
# show ip ospf neighbor
This command confirms if OSPF has formed adjacency with neighbors and shows the current state of each neighbor relationship.
The output details each OSPF neighbor's router ID, state (e.g., Full for a complete adjacency), and the interface it's connected on.
# show ip ospf interface
To diagnose OSPF interface-specific issues, such as problems with timers or MTU mismatches, use this command.
The output includes the cost, state, and neighbors connected to each OSPF-enabled interface, providing a comprehensive look at how OSPF is operating on the router.
# show running-config
This command displays the current active configuration in the device's memory. It's useful for verifying changes that have not yet been saved to the startup configuration.
# show ip interface brief
The output from this command provides a concise table of interfaces, showing their IP addresses, statuses, and protocol states, which is helpful for a quick check of interface operations.
# show ip dhcp binding
This displays the list of all IP addresses assigned by the DHCP server to clients, along with their MAC addresses, lease time, and type of binding.
# show access-lists
Shows all configured access lists and their conditions. It's a quick way to review which access control entries are configured and how many packets matched each entry.
# show ip eigrp neighbors
Useful for verifying EIGRP-established adjacencies, this command shows neighboring routers connected via EIGRP and includes details such as the hold time and last heard timer.
# show version
Displays the router or switch's hardware model, software version, names and sources of configuration files, the last reboot reason, and additional information about the hardware platform.
# show ntp status
This command is used to verify the status of NTP synchronization on the device.
It tells you if the device is synchronized with an NTP server, the stratum level, and the reference IP address of the NTP source.
Network Utilities
# show arp
Show arp provides the Address Resolution Protocol (ARP) table of the device.
It maps IP addresses to MAC addresses for all interfaces, which is crucial for troubleshooting network connectivity issues.
# show mac address-table
This command displays the MAC address table, which contains all learned MAC addresses and their associated VLAN and port information.
It's essential for diagnosing issues with MAC address learning and switch port mappings.
# show vlan
# show vlan int br
This command displays information about the VLANs currently running in the switch, including VLAN ID, name, and the ports assigned to them.
Useful for verifying VLAN configurations.
# show interfaces trunk
Lists the trunking status of interfaces, showing the native VLAN and the allowed VLANs on each trunk port.
# show ip nat translations
Displays the Network Address Translation (NAT) translations table, helpful for troubleshooting NAT configurations by showing active translation entries.
# show standby
Used to display the status of Hot Standby Router Protocol (HSRP) configurations, showing the state, priority, and the IP address of the standby router.
# show etherchannel summary
Provides an overview of the EtherChannel status, including the group number, ports involved, and their status, which is key in verifying link aggregation setups.
# show port-security
Displays the port security configuration on interfaces, including the maximum number of secure MAC addresses, current count of secure MAC addresses, and security violation counts.
Cisco Discovery Protocol (CDP) is a proprietary Layer 2 protocol used by Cisco devices to discover information about directly connected devices, such as model, port number, and IP address.
# show cdp neighbors
This command lists all directly connected Cisco devices. Useful for network topology mapping and troubleshooting connectivity issues.
# show cdp interface <interface_name>
Displays CDP information specific to a particular interface, including the frequency of CDP updates and the hold time for CDP packets.
-
Clone the repo:
git clone https://github.com/MrPenguin07/cisco-cheatsheet cd !$ -
Install python requirements (for ftp server):
pip install -r requirements.txt -
Run python ftp_server.py
python3 ftp_server.py -
Pull a script onto a network device (WARNING: Backup to avoid any losses)
Switch#> copy ftp://192.168.1.10/sw_base.txt running-configReplace 192.168.1.10 with the IP of the computer connected to the switch or router.
Set the default configuration with stty to cisco console default, 9600 bps, 8N1, no flow control:
stty -F /dev/ttyUSB0 9600 litout -crtscts
or:
stty -F /dev/ttyUSB0 cs8 -parenb -cstopb -echo raw speed 9600
# What the arguments mean:
# cs8: 8 data bits
# -parenb: No parity (because of the '-')
# -cstopb: 1 stop bit (because of the '-')
# -echo: Without this option, Linux will sometimes automatically send back
# any received characters, even if you are just reading from the serial
# port with a command like 'cat'. Some terminals will print codes
# like "^B" when receiving back a character like ASCII ETX (hex 03).
Perform a Boot Interupt to Recover a lost or unknown password
WARNING: This operation will delete all current config on the device
-
Ensure Console Cable is connected at 9600 Baudrate
-
Backup config if you need
-
Unplug Power
-
Wait for a few seconds
-
Re-insert the power cord to the switch
-
Within 15 seconds, hold the
Modebutton until the green flashing light flashes amber and then returns to flashing green. Release theModebutton. -
Something like the following should display:
initialize the flash file system, and finish loading the operating system software# flash_init load_helper boot -
Run
flash_init -
Run
copy flash:config.text flash:config.text.old -
Run
bootThe device should now boot with no config and grant you access to it.
Set up a local FTP/TFTP server, there's a simple python script included here
Transfer firmware to the device using a TFTP server:
conf t
copy tftp: flash:
address or name of remote host []? <tftp_server_ip>
source filename []? <firmware_filename>
destination filename []? <firmware_filename>
Replace <tftp_server_ip> with the IP address of your TFTP server, and <firmware_filename> with the name of the firmware file.
Transfer firmware to the device using an FTP server:
conf t
copy ftp: flash:
address or name of remote host []? <ftp_server_ip>
username []? <username>
password []? <password>
source filename []? <firmware_filename>
destination filename []? <firmware_filename>
Replace <ftp_server_ip> with the IP address of your FTP server, and with your FTP credentials, and <firmware_filename> with the name of the firmware file.
Transfer firmware from the device to a TFTP server:
conf t
copy flash: tftp:
source filename []? <firmware_filename>
address or name of remote host []? <tftp_server_ip>
Replace <firmware_filename> with the name of the firmware file, and <tftp_server_ip> with the IP address of your TFTP server.
Transfer firmware from the device to an FTP server:
conf t
copy flash: ftp:
source filename []? <firmware_filename>
address or name of remote host []? <ftp_server_ip>
username []? <username>
password []? <password>
Replace <firmware_filename> with the name of the firmware file, <ftp_server_ip> with the IP address of your FTP server, and and with your FTP credentials.
For this you will need a USB console cable. These can be picked up on amazon for about $9-$12.
-
Connect your the USB console cable from the computers usb port to the cisco RJ-45 console port.
-
Install the
screenprogram if you dont already have it.
apt install screen
- Find the USB device.
If its the first USB serial device you plugged in, it should be /dev/ttyUSB0. The second one should be /dev/ttyUSB1, etc.
You can verify with with ls /dev | grep USB
- Run
screen
You will need root access or preferably to add your user into the dialout group (true for most linux distros I believe).
screen /dev/ttyUSB0
Running with a specific baudrate.
screen /dev/ttyUSB0 9600
screen /dev/ttyUSB0 115200
To exit screen, hit Ctrl-a, Ctrl-d
If you have trouble with the connection, e.g. it lags or is funky, cisco serial connections require the following settings by default:
9600baud8data bitsnoparity1stop bitnoflow control
To do that exactly with screen:
screen /dev/ttyS0 9600,cs8,-parenb,-cstopb,-hupcl
screen /dev/ttyS0 19200,cs8,-parenb,-cstopb,-hupcl
screen /dev/ttyS0 115200,cs8,-parenb,-cstopb,-hupcl
With odd parity:
screen /dev/ttyS0 9600,cs8,parenb,parodd,-cstopb,-hupcl
With even parity:
screen /dev/ttyS0 9600,cs8,parenb,-parodd,-cstopb,-hupcl
See @MrPenguin's cisco-send repository; cisco-send
Howto coming soon!
Howto coming soon!
(actually it won't, not by me, accepting PR heh)
To enable configuration archiving and set the storage path.
Set the archive path where config files will be saved.
Router# conf t
Router(config)# archive
Router(config-archive)#path ?
flash: Write archive on flash: file system
ftp: Write archive on ftp: file system
http: Write archive on http: file system
https: Write archive on https: file system
pram: Write archive on pram: file system
rcp: Write archive on rcp: file system
scp: Write archive on scp: file system
tftp: Write archive on tftp: file system
Router(config-archive)# path flash:
Router(config-archive)# end
Example how to start a rollback timer (e.g., 1 minute),
make changes then revert.
Router# configure terminal revert timer 1
Router(config)# hostname I-Changed-This
I-Changed-This(config)# end
To reset or extend the rollback timer (e.g., add 20 minutes):
Router# configure revert timer 20
To force a manual rollback to the archived configuration:
Router# conf t
Router(config)# hostname I-Changed-This
I-Changed-This(config)# end
I-Changed-This# configure revert now
Router#
After thoroughly testing changes,
you may cancel the rollback process:
Router# configure confirm
Remember, these commands should be used with caution and tested during maintenance windows to prevent unexpected behaviour.
In most distro's package repositories; something resembling <package manager> install ipcalc
$ tldr ipcalc
Perform simple operations and calculations on IP addresses and networks.
More information: <https://manned.org/ipcalc>.
Show information about an address or network with a given subnet mask:
$ ipcalc 1.2.3.4 255.255.255.0
Show information about an address or network in CIDR notation:
$ ipcalc 1.2.3.4/24
Show the broadcast address of an address or network:
$ ipcalc -b 1.2.3.4/30
Show the network address of provided IP address and netmask:
$ ipcalc -n 1.2.3.4/24
Display geographic information about a given IP address:
$ ipcalc -g 1.2.3.4
Example
$ ipcalc 1.2.3.4/24
ipcalc 1.2.3.4/24
Address: 1.2.3.4 00000001.00000010.00000011. 00000100
Netmask: 255.255.255.0 = 24 11111111.11111111.11111111. 00000000
Wildcard: 0.0.0.255 00000000.00000000.00000000. 11111111
=>
Network: 1.2.3.0/24 00000001.00000010.00000011. 00000000
HostMin: 1.2.3.1 00000001.00000010.00000011. 00000001
HostMax: 1.2.3.254 00000001.00000010.00000011. 11111110
Broadcast: 1.2.3.255 00000001.00000010.00000011. 11111111
Hosts/Net: 254 Class A
In most distro's package repositories; something resembling <package manager> install whatmask
Example
$ whatmask 10.0.1.12/30
------------------------------------------------
TCP/IP NETWORK INFORMATION
------------------------------------------------
IP Entered = ..................: 10.0.1.12
CIDR = ........................: /30
Netmask = .....................: 255.255.255.252
Netmask (hex) = ...............: 0xfffffffc
Wildcard Bits = ...............: 0.0.0.3
------------------------------------------------
Network Address = .............: 10.0.1.12
Broadcast Address = ...........: 10.0.1.15
Usable IP Addresses = .........: 2
First Usable IP Address = .....: 10.0.1.13
Last Usable IP Address = ......: 10.0.1.14