Yes, it prevents loops in spanning tree on layer 2 switches from causing a loop by disabling the port on a cisco switch...
Larry Letterman Network Engineer Cisco Systems > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of > Thomas N. > Sent: Wednesday, April 02, 2003 12:18 PM > To: [EMAIL PROTECTED] > Subject: Re: VLAN loop problem [7:66656] > > > What does "portfast bpdu-guard" do? Does it prevent interfaces with > portfast enabled from causing the loop in my scenario? > > > ""Larry Letterman"" wrote in message > news:[EMAIL PROTECTED] > > > port mac address security might work, altho its a lot of admin > > overhead..are you running portfast bpdu-guard on the access ports? > > > > > > Larry Letterman > > Network Engineer > > Cisco Systems > > > > > > ----- Original Message ----- > > From: Thomas N. > > To: [EMAIL PROTECTED] > > Sent: Tuesday, April 01, 2003 8:14 PM > > Subject: VLAN loop problem [7:66656] > > > > > > Hi All, > > > > I got a problem in the production campus LAN here between > VLANs. Please > > help me out! Below is the scenario: > > > > We have VLAN 10 (10.10.x.x) and VLAN 20 (10.20.x.x) subnets. > Routing is > > enable/allowed between the two subnets using MSFC of the 6500. Each > subnet > > has a DHCP server to assign IP address to devices on its subnet. > > Spanning-tree is enable; however, portfast is turned on on all > > non-trunking/uplink ports. Recently, devices on VLAN 10 got > assigned an > IP > > address of 10.20.x.x , which is from the DHCP on the other scope and > also > > from 10.10.x.x scope, and vice versa. It seems that we a > loop somewhere > > between the 2 subnets but we don't know where. I noticed lots of end > users > > have a little unmanged hub/switch hang off the network jacks in their > > cubicals and potentially cause loop. > > > > Is there any way that we can block the loop on the Cisco switches > without > > visiting cubicals taking those little umanaged hubs/switches? Thanks! > > > > Thomas Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=66714&t=66656 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
