I have the following setup:


I'm unable to enable Fa0/5. The switch configuration for that port is correct

AS22 configuration

No configuration has been made on the server side:

server side

Assigning Ip adresses has not solved the problem.

Vlan is also correct according to output

AS22 show vlan

  • What equipment is it? Switch? Router? Model information? According to your picture, the port is already enabled and appears to be a switch port assigned to access mode for VLAN 242. Perhaps the link is down because the server is not turned on? May 4, 2023 at 23:57
  • It is a simulation in packet tracer. Swtich is of type 2960 - 24TT. Serer is on.
    – Rubus
    May 5, 2023 at 6:36
  • Has any answer solved your question? Then please accept it or your question will keep popping up here forever. Please also consider voting for useful answers.
    – Zac67
    Oct 2, 2023 at 12:31

1 Answer 1


After some experimentation I realized the problem was the "sticky" keyword line in the switch configuration. If the sticky keyword is used, as in the second last line, the switch learns the MAC address of the device connected to it and saves it in the configuration, as in the last line. This line has to be removed if you want to use other devices with different MAC addresses on this port.

 interface FastEthernet0/9
 switchport access vlan 240
 switchport mode access
 switchport port-security
 switchport port-security mac-address sticky 
 switchport port-security mac-address sticky 000A.F3DA.6D47
  • On a real switch the link (physical layer) would come up but subsequent communication on the data link layer would fail.
    – Zac67
    May 5, 2023 at 9:41
  • @Zac67 Yes, that's why I did not suspect the switch configuration to be the source of the problem. Another error in packet tracer, thanks for pointing it out!!
    – Rubus
    May 5, 2023 at 9:55

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