Category Archive: Switch

Jan 29

CDP and LLDP on Cisco catalyst switch

CDPvsLLDP

CDP and LLDP are both discovery protocols used to find information about first hop neighbor network devices. The Cisco Discovery Protocol (CDP) is a proprietary Data Link Layer protocol developed by Cisco Systems. It is used to share information about other directly connected Cisco equipment, such as the operating system version and IP address. CDP …

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Aug 21

DHCP Snooping on Cisco Catalyst Switch

dhcpsnooping

DHCP snooping acts like a firewall between untrusted hosts and trusted DHCP servers. DHCP snooping performs the following activities: • Validates DHCP messages received from untrusted sources and filters out invalid messages. • Builds and maintains the DHCP snooping binding database, which contains information about untrusted hosts with leased IP addresses. • Uses the DHCP …

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Aug 21

How to deny access for servers in the same VLAN on Cisco switch

In this scenario we have two servers connected on the same VLAN so typically they will be able to communicate directly and do not pass default gateway where you could perform ACL filtering. To disallow network devices from direct communication use command “switchport protected” under interface configuration. Configuration Example: enable configure terminal ! interface FastEthernet0/1 …

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