Hi, If you find out whic port/interfaces are your uplinks you can exclude these port from your mac address table search sh cdp nei | ex SEP|ATA this will show all neighbors except CISCO PHONES/ATAs Now you can add the uplink ports as exclusions to your MAC search - something like this sh mac add | ex CPU|1/1/1|1/1/2 This would exclude my local CPU and my interfaces gig1/1/1 & gig 1/1/2 ... View more

Hi,   If you are having issues with this module have a read at this link https://www.cisco.com/c/en/us/support/docs/field-notices/643/fn64321.html May be you are being hit with that issue.. ... View more

Hi, To support up to 40KM on the 3850-XS you will need a GLC-EX-SMD SFP.   More info can be seen here:- https://www.cisco.com/c/en/us/products/collateral/interfaces-modules/gigabit-ethernet-gbic-sfp-modules/product_data_sheet0900aecd8033f885.html   ... View more

Hi, You can find the NIM modules for your 4221 here:- https://www.cisco.com/c/en/us/products/routers/4000-series-integrated-services-routers-isr/relevant-interfaces-and-modules.html     ... View more

Hi, Looks like you are hitting bug CSCuh77261 This affects your IOS version 15.0.2SE2. If you want to remain on the 15.0.2 train then go to 15.0.2SE12 ... View more

Hi, Can you check your power supply types - ,Im not sure if you have POE capable PSUs   show env power all   ... View more

Hi, Most DHCP servers Including the Cisco IOS type should perform a ping before giving out a lease of an IP address. It the address responds due to say some one has blagged it for a static the DHCP server should mark this as a bad address in its lease table.   https://www.cisco.com/en/US/docs/ios/12_4t/ip_addr/configuration/guide/htdhcpsv.html#wp1027188 Ping Packet Settings By default, the DHCP server pings a pool address twice before assigning a particular address to a requesting client. If the ping is unanswered, the DHCP server assumes (with a high probability) that the address is not in use and assigns the address to the requesting client. By default, the DHCP server waits 2 seconds before timing out a ping packet.   1. enable   2. configure terminal   3. ip dhcp ping packets number   4. ip dhcp ping timeout milliseconds   Here is an old MS link for a 2003 server to do conflict prevention https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2003/cc737924(v=ws.10)   ... View more

Hi Richard, You will need to configure IP connectivity between the 2 routers on the f0/0 interfaces. Router 1 ! int f0/0 ip add 192.168.0.1 255.255.255.252 no shut ! Router 2 ! int f0/0 ip add 192.168.0.2 255.255.255.252 no shut ! The router with wanted IOS will need to become a tftp server ! tftp-server flash:my-ios-file.bin ! On the other router copy the file accross using tftp copy tftp flash 192.168.0.1 my-ios-file.bin   ... View more

Hi,   Can you try :-   show spanning-tree interface gigx/x/x    Hopefully you will see an output something like this Port 3 (GigabitEthernetx/x/x) of VLAN0101 is designated forwarding  <SNIP>    The port is in the portfast mode    Link type is point-to-point by default    Bpdu guard is enabled by default    BPDU: sent 6575235, received 0    Port 3 (GigabitEthernetx/x/x) of VLAN801 is designated forwarding  <SNIP>    Number of transitions to forwarding state: 1    The port is in the portfast mode    Link type is point-to-point by default    Bpdu guard is enabled by default    BPDU: sent 6575160, received 0     ... View more