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:
Category Archives: Cisco
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: Let’s see the active firmware version:
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 […]
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:
Back Up Cisco Catalyst 6500 Configuration
For the test, I sketched a Cisco Catalyst 6509-E automatic backup configuration script. Actually the script itself: 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: The file can be opened for example in the text editor nano (Ctrl+X […]
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): Now I’ll give an example of setting Trunk of the port (traffic goes through one or several vlan with a tag only): And […]
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:
Configuring HTTP on Cisco
Connect to the Cisco switch and go into elevated privilege mode: Now go into the configuration mode: Enable HTTP: If necessary, you can disable HTTP and HTTPS as follows: Add a user if it does not exist: If you want to allow HTTP access to only certain IPs, then let’s see what rules there are […]
Using third-party SFP modules in Cisco switches
Suppose we connected a third-party module to the first SFP port, we’ll look at the information about it: In my case, on the Cisco Catalyst 6509-E, very many ports with third-party SFP modules after some time they turned off and in the logs information was written that the module was not supported. Now go into […]
Configuring NetFlow on Cisco
Let’s say we have a collector running like I wrote in this article – Installing and using flow-tools Now connect to the Cisco switch, for the test, I connect to the Cisco Catalyst 6509-E. Now go into the configuration mode: Enable NetFlow: Specify NetFlow parameters, collector address, port and version: Suppose you need to collect […]