I am attempting to learning CCNA on my own and I have no experience in networking prior to this. I tried to connect a pc and a router (generic router) in Packet Tracer directly but the link between the devices displayed red dots. The status of both the ports Fa0 and Fa0/0 shows "Link down". I used a copper straight through cable to connect both the devices. I also used the "no shut" command after logging into the router's interface command line but it made no difference.

I then set up the same network using a switch to connect the same pc and router and it worked. So what am I doing wrong when using just the pc and the router arrangement?

I am using packet tracer 7.0

  • Connecting a PC to any cisco network device requires a console cable Commented Mar 6, 2019 at 7:14

2 Answers 2


You'll need a crossover cable to connect two MDI devices without auto-crossover. The switch presents MDI-X.


  • Thanks for the answer but if I am not mistaken, a straight through cable is used to connect two unlike devices and a cross over is used to connect like devices. You said that I should use a cross over cable to connect a pc and a router. Is that correct? Commented Sep 15, 2018 at 21:07
  • 2
    You're correct about like-to-like needing crossover; where you're going wrong is that a pure router is MDI, like a PC. Only switches normally present MDI-X. It can be confusing because domestic routers normally normally also contain a switch in them, and its the switch's MDI-X sockets on the back of the "router".
    – jonathanjo
    Commented Sep 16, 2018 at 10:26
  • Thanks. I think my question has been answered so this topic can be closed. Commented Sep 18, 2018 at 10:56

If it is still not working (if it is still red on the wire) try changing the bandwidth to 'auto' in the router interface which is connected to the PC. [click on the router > config > choose the correct GigabitEthernet interface > Bandwidth > click on auto]. I don't know the exact reason, but it worked for me. enter image description here

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