I will use Cisco Catalyst 6509-E on the test.
To view the temperature of the sensors, connect via the console or telnet for example and execute the command:
Category Archives: Cisco
List of SNMP OID and MIB for Cisco
Below is the list of SNMP OID that I used to create templates in Zabbix and other scripts.
Continue reading “List of SNMP OID and MIB for Cisco”Solution “Port is not compatible with aggregators in channel 1 and cannot attach to them”
Once on Cisco Catalyst 6509-E, when I collected an aggregation of three ports, traffic began to go through only two ports and a message appeared in the logs:
Continue reading “Solution “Port is not compatible with aggregators in channel 1 and cannot attach to them””Cisco Catalyst 2960-24TT-L Firmware Update
On the test, I will upgrade the Cisco Catalyst WS-C2960-24TT-L switch.
And so, let’s connect to the switch and switch to elevated privilege mode:
enable
Let’s see the active firmware version:
show version show boot
Continue reading “Cisco Catalyst 2960-24TT-L Firmware Update”
Configure IP Unnumbered on Cisco
On the test I will configure IP Unnumbered on Cisco Catalyst 6509E with firmware 12.2(33)SXJ7, on other switches the setup is similar.
IP Unnumbered is useful, for example, when it is necessary to divide a large network into several VLANs and use the same IP addresses and also to issue white IPs in any VLAN using one gateway.
Connect to the terminal device through the console, telnet or SSH.
Configuring IGMP snooping on Cisco
I will give an example of setting up IGMP snooping on Cisco, there was a Cisco WS-C2960-24TT-L switch at hand.
First of all, let’s switch to configuration mode:
enable configure t
Back Up Cisco Catalyst 6500 Configuration
For the test, I sketched a Cisco Catalyst 6509-E automatic backup configuration script.
Actually the script itself:
#!/bin/bash
# Backup CISCO config
(
sleep 5
echo "user"
sleep 4
echo "password"
sleep 4
echo "copy running-config tftp:"
sleep 2
echo "192.168.1.4"
sleep 2
echo "cisco.cfg"
sleep 6
echo "exit"
) | telnet 192.168.1.5
mv /srv/tftp/cisco.cfg /backups/devices/cisco/`date +%Y-%m-%d`_cisco.cfg
find /backups/devices/cisco/ -type f -mtime +30 -exec rm {} \;
Add the contents of the script, for example, to the backup_cisco.sh file and add it to cron, adding the following line to the /etc/crontab file:
0 2 * * * root /backups/scripts/backup_cisco.sh > /dev/null 2>&1
The file can be opened for example in the text editor nano (Ctrl+X to exit, y/n to save or cancel changes):
sudo nano /etc/crontab
The script connects via telnet to 192.168.1.5 and copies the configuration to the tftp server 192.168.1.4, then the file is moved to a convenient directory for storage.
The last line in the script deletes files older than 30 days.
How to start the tftp server, see my articles: Installing and Configuring a TFTP Server in Ubuntu or Starting a TFTP server in Windows.
See also: Using and configuring CRON.
Configuring ports in Cisco switches
For the test I will configure ports on Cisco Catalyst 6509-E.
I’ll give an example of setting Access of the port (the traffic goes only over one specified vlan without a tag):
interface GigabitEthernet1/1 description TEXT switchport switchport access vlan 226 switchport mode access no shutdown
Now I’ll give an example of setting Trunk of the port (traffic goes through one or several vlan with a tag only):
interface GigabitEthernet1/2 description TEXT switchport switchport trunk encapsulation dot1q switchport trunk allowed vlan 207,228 switchport mode trunk no shutdown
And the third option, Hybrid port (traffic goes only on one vlan without a tag and on one or several vlan with a tag):
interface GigabitEthernet1/3 description TEXT switchport switchport trunk encapsulation dot1q switchport trunk native vlan 226 switchport trunk allowed vlan 207,226 switchport mode trunk no shutdown
To specify parameters for several ports at once:
interface range GigabitEthernet1/1-24
We prohibit automatic switching of the port to access or trunk mode:
interface range GigabitEthernet1/1-24 switchport nonegotiate exit
See also my article – Configuring link aggregation on the Cisco Catalyst 6500
Blocking third-party DHCP on Cisco via DHCP Snooping
On the test, I configure DHCP Snooping on the Cisco Catalyst 6509-E to block third-party DHCP servers, on the other Cisco switches, the configuration is basically the same.
After connecting to the device immediately go to the configuration mode:
enable configure
Continue reading “Blocking third-party DHCP on Cisco via DHCP Snooping”
Configuring HTTP on Cisco
Connect to the Cisco switch and go into elevated privilege mode:
enable
Now go into the configuration mode:
configure terminal
Enable HTTP:
ip http server ip http authentication local
If necessary, you can disable HTTP and HTTPS as follows:
no ip http server no ip http secure-server
Add a user if it does not exist:
username NAME privilege 15 secret PASSWORD
If you want to allow HTTP access to only certain IPs, then let’s see what rules there are on the switch:
exit show access-list show ip access-lists configure terminal
If there is no necessary rule, then we will create:
access-list 10 permit 192.168.1.22 access-list 10 permit 192.168.3.10
See my article – Restricting access to the Cisco Catalyst 6500 management
Apply the rule to HTTP:
ip http access-class 10
To cancel it is possible so:
no ip http access-class 10
If you need to specify the maximum number of connection attempts:
ip admission max-login-attempts 5 show ip admission configuration
Leave their configuration mode and save the configuration:
exit write
See also:
Configuring Cisco devices