Cisco switchingrouting 3750 portsecurity will not clear jun 5, 2012. Port security is a topic on the ccent exam and its important to know what it is and how to configure it. To configure a static mac address, the following command is used. So when the device would start to communicate with its actual mac, port security would think that it was a second mac on the port and shut it down. By configuring port security you can make sure that only certain mac addresses are allowed to connect to certain switch ports and if others are detected, these ports can be shutdown. Dynamic the entry is created from the incoming frames by reading the source mac address field in the ethernet header. How to enable or disable port security on a cisco switch. If you have 1 port in network a and 1 port in network b separate vlans then the switch will be able to route between net a and b and vice versa. I have seen in a simulator of a 2960 wsc296024tt, ios 12. We normally turn on port security and set the maximum mac addresses to 1 the default or 2 if there is an ip phone connected. I have a new cisco 3750 switch with several things plugged into it and active, and the macaddresstable is not showing anything but this. Cisco switch port security commands the tech factors. Port security is one of the methods for restricting unauthorized access to your switch ports.
Cisco 3750 stacking configuration router switch blog. Catalyst 3750 switch software configuration guide, cisco ios. The command to configure this is as follows, switchport portsecurity maximum n where n. Use show portsecurity interface to see the port security details per interface. This enables the port security on the switchport with the defaults 1 mac address allowed, 1st connected mac address, disable port if there is a violation if you know the mac address of the device and that thats the only device that connects to the swicthport for example, a server on a serverfarm switch then you can set the macaddress manually. Port security is normally configured on ports that connect servers or fixed devices. Follow these guidelines when configuring port security. When stacking multiple cisco switches together in a stack there needs to be one switch in the stack that is. How to configure the maximum number of mac addresses. As stated above, it defeats the purpose of portsecurity. This will learn the first mac address that comes into on the interface or interfaces.
Verify port security is enabled and the mac addresses of pc1 and pc2 were added to the running configuration with show run command. The best advise is to follow this video through, then. The mac notification history table stores mac address. From global configuration mode enter in specific interface. Try to test your switch port security configuration with ping command and testing with the rogue laptop on the lab. Here is a useful command to check your port security configuration. Port security secures the access to an access or trunk port based on mac address. To enable portsecurity youll execute the switchport portsecurity command as previously learned in lab 419. Configure cisco port security on switches and router. Table 4 commands for displaying port security status and configuration. Cisco 3750 macaddress problem solutions experts exchange. Page 104 chapter 2 catalyst 3750 switch cisco ios commands deny mac accesslist configuration lsap lsapnumber mask optional use the lsap number 0 to 65535 of a packet with 802. Static secure mac addressesthese are manually configured by using the switchport portsecurity macaddress macaddress interface configuration command.
It enables an administrator configure individual switch ports to allow only a specified number of source mac addresses ingressing the port. For example, the following set of commands will assign the mac address of 1111. Using vmps or dynamic vlans you create a list of authorized mac addresses for exactly the purpose you describe. These commands display information helpful in diagnosing and resolving internetworking problems and should be used only under the guidance of cisco technical support staff. If you enable switch port security, the default behavior is to allow only 1 mac address, shutdown the port in case of security violation and sticky address learning is disabled. At this stage, i must explain the difference between dynamic and static entries in the mac address table. It limits the number of learned mac addresses to deny mac addressflooding. The port led is set to the orange color and, when you issue the show interfaces command, the port status shows as errdisabled. These switches provide high availability, scalability, security, energy efficiency, and ease of operation with innovative features such as cisco stackpower available only on the catalyst 3750x, ieee 802. From privilege exec mode use configure terminal command to enter in global configuration mode. Although the main purpose of the switch is to provide interconnectivity in layer 2 for the connected devices of the network, there are myriad features and functionalities that can be. Port security is a layer two traffic control feature on cisco catalyst switches. Cisco switch port security configuration and best practices. Static secure mac addressesthese are manually configured by using the switchport portsecurity macaddress macaddress interface.
Catalyst 3750 switch command reference, release 12. To configure port security we need to access the command prompt of switch. Solved changing a cisco 3750 to a router spiceworks. We have 12 cisco catalyst 3750e series manuals available for free pdf download. Cisco integrated security features include port security, dhcp snooping, dynamic arp inspection, and ip source guard. Port security is normally configured on ports that connect servers or fixed devices, because the likelihood of the mac address changing on that port is low. Catalyst 3750 switch software configuration guide, release 12. No switchport portsecurity no switchport portsecurity violation protect no switchport portsecurity macaddress sticky no switchport mode access. To verify the configuration, we can use the show mac address table command. A secure port cannot be a destination port for switch port analyzer span. I have a customer with a stack of 9 catalyst 375048ps. The mac address learned on the port can be added to stuck to the running. Such as the free solarwinds tftp server using hyperterminal to telnet to switch, at the enable prompt. The cisco ip phone address is learned on the voice vlan.
Click switch and click cli and press enter key port can be secure from interface mode. So if you wanted to have the switch route between two networks then you would. Enable portsecurity on sw1s fa01 interface and configure the interface to sticky the mac address learned. A secure port and static mac address configuration are mutually exclusive. Note you can disable ntp packets from being received on routed ports and vlan interfaces. As you see, the mac address of the r1 e00 interface has been learned dynamically from the incoming frames on sw1 port f01. This chapter describes how to configure the portbased traffic control features on the catalyst 3750 switch.
Cisco 3750 and mac address filtering solutions experts. If the port violates the port security, we can shutdown that port automatically. Next, we will enable dynamic port security on a switch. When you enable port security on an interface that is also configured with a voice vlan, set the maximum allowed secure addresses on the port to two. After specifying the port to make changes to, the following commands will be entered. Cisco switch port security how to configure switch. The mac address learned on the port can also be added to the running configuration of that port. I recently started reevaluating how we do port security as a result of a recent customers information security audit. To set the maximum number of max addresses allowed on a port when portsecurity is configured, the port security maxmaccount command can be used on 2900 and 3500 xl switches and the switchport portsecurity maximum command can be used on 2940, 2950 and 2955, 2970, 3550 or 3750 series of switches when one of these commands are issued, mac address entries are not. Catalyst 3750 command reference, cisco ios release 12.
One way to boost network security is to use ciscos port security feature to lock down switch ports. Catalyst 3750g integrated wireless lan controller switch 2475. Attach rogue laptop to any unused switch port and notice that the link lights are red. I have configured one port in a 3750 x series with the following commands and the voip phone was showing configuring ip. You can see the violation mode is shutdown and that the last violation was caused by mac address 0e. The default behavior is to disable the port when the mac changes or if the number of concurrent macs exceeds the maximum. We have mac address stick set up on all access ports. Catalyst 3750 switch software configuration guide, 12. I also have the cisco press ccna flashcards book also, and that only mentions the first command above. How to restore cisco ios switch catalyst 3750 series.
Assign another port say gigabitethernet002 to another vlan say vlan 2. Also note if you are watching the bootup of the switch stack on the console port of one of the switches you can see during the bootup process what switch was elected master. Cisco port security and sticky mac addresses conetrix. The basic cli commands for all of them are the same, which simplifies cisco device management.
We will look specifically at configuring static, dynamic and sticky secure mac addresses as. If this setting is not applied the default of one mac address is used. Enter interface configuration mode, and specify the. Catalyst 3750x and 3560x switch software configuration guide. Here is a cisco commands cheat sheet that describes the basic commands for configuring, securing and troubleshooting cisco network devices. Port security issue 80059 the cisco learning network.
How to configure port security on a cisco switch youtube. When a port is in errordisabled state, it is effectively shut down and no traffic is sent or received on that port. If the switch port was configured by using the auto qos voip ciscophone interface configuration command in cisco ios release 12. Use the clear portsecurity privileged exec command to delete from the mac address table all secure addresses or.
Cisco switchingrouting 3750 portsecurity will not clear. To configure the port to learn only one mac address, set the maximum to 1. When the port is connected to a cisco ip phone, the ip phone requires one mac address. How to configure switch port security on cisco switches. A secure port cannot belong to an etherchannel portchannel interface. The default configuration of a cisco switch has port security disabled. Catalyst 3750 switch cisco ios commands shutdown through vtp. Cisco 3750x set switch priority in stack kyle kowalczyk. The cisco ip phone address is learned on the voice vlan, but is not learned on the access vlan. In macflooding, an attacker can connect a laptop into an empty switch port or empty rj45 wall socket, and he can use hacking tools to generate millions of ethernet frames with fake source mac. Unless otherwise noted, the term switch refers to a standalone switch and a switch stack. These are the same commands as were used to enable port security, with the addition of no in front of each line. For syntax information, see the cisco ios security command reference, release 12.
Learn the basics of port security, and find out how to configure this feature. Cisco switch commands cheat sheet cli cisco switches can be used as plugandplay devices out of the box but they also offer an enormous amount of features. Catalyst 3750 switch cisco ios commands aaa accounting. This appendix describes the show platform privileged exec commands that have been created or changed for use with the catalyst 3750 switch.
Port security is easy to configured and it allows you to secure access to a port based upon a mac address basis. Almost all cisco devices use cisco ios to operate and cisco cli to be managed. The below output is an example of configuring port security on a range of ports fa01 10, for this example the maximum mac addresses i want on one port is two, i also want the violation to change from the default setting to restrict. Interface configuring port security cisco catalyst 3850. Port security can also configured locally and has no mechanism for controlling port security in a centralized fashion for distributed switches. For example, port security on cisco switches can be used to stop macflooding attacks or prevent nonauthorized hosts to connect to the switch. Cisco port security on a 3750 ars technica openforum. We have several 3750 stacks across our campus that we are unable to completely clear port security on. The show stormcontrol and show portsecurity privileged exec commands display those storm control and port security settings. Cisco catalyst 3750x series switches date sheet cisco. In this video we are going to be configuring the cisco portsecurity feature on a catalyst 3560 switch. How to configure the port to add the mac address to the running configuration. Revered cisco family, ive observed, as stated in the books, and also as experienced in the real world, that resuscitating an errordisabled port for a 2960 sw 80059. Configuring sticky switchport security free ccna workbook.
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