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I am connecting a brand-new Catalyst 2950 switch to my LAN. It is on with green lights, and frames successfully go in and out the ports. The switch is on the same LAN has my host PC, and pings are successful. I had an RJ-45 Ethernet cable connecting a switch port directly to my PC network interface, with the intention to telnet to the switch, but apparently the switch refuses the telnet connections if no password is set. I tried telnet through Linux to the switch but still get the "Password required, but none set" message from IOS. So it looks like a console connection is required to set the login and password. But when my putty client (I'm running Windows 7), with serial COM1 settings tries to connect to the switch's IP, I just get a blank Putty terminal. The switch's console port is RJ-45 and so is my PC's Ethernet adapter. Could the problem be that a console connection setup like this will not work with a regular Ethernet cable? Is a crossover cable the solution to getting a telnet connection to the switch?

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4 Answers 4

up vote 2 down vote accepted

Had the same issue. They have made it even easier to configure these things.

Read the "getting started" portion of link below. All you need is a straight through cable and just run through the setup real quick and enable telnet. Then you can telnet to it and set what you need to configuration wise. A lot easier than hyperterm and a console cable in my opinion.

Make sure to pay attention when it says that the switch acts as its own DHCP server in express setup mode. Could create havoc on your network if you don't use it standalone until you get it setup. Also boot times seem to be a lot longer with the newer ones than the ones I was used to back in 2004.

http://www.cisco.com/en/US/docs/switches/lan/catalyst2950/hardware/quick/guide/2950gsg2.html#wp49930

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You're on the right track with the crossover cable, but not quite. You need a rollover cable instead.

enter image description here

Your typical connection chain is going to be...

  • PC
  • USB-to-Serial Adapter OR Serial Port
  • Serial to RJ-45 Adapter
  • Rollover cable
  • Device Console

The console cable that comes with Cisco devices combines the Serial-to-RJ45 adapter and rollover cable.

Standard port settings are...

  • Bits per sec : 9600
  • Data bits : 8
  • Parity : none
  • Stop bits : 1
  • Flow control : none

Hope this helps.

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You need an RJ45 adapter.

Management console port: 8-pin RJ-45 connector, RJ-45-to-DB9 adapter cable for PC connections; for terminal connections, use RJ-45-to-DB25 female data-terminal-equipment (DTE) adapter (can be ordered separately, Cisco part number ACS-DSBUASYN=)

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If you can telnet to the switch to see the no password set prompt, then try the web interface. If it is there and enabled (while network engineers often disable/remove it due to security concerns, often these are run by systems/network guys who don't know to do so), then you can configure login and a password on the vty lines.

If you do have access to the web interface, you can enter commands from there. I have run across problems when trying to click on some of the commands, but if you watch the URL patterns change as you click the links, you will figure out fairly quickly how to issue commands directly on the URL.

I recently did this on a 3550 for a friend over a remote desktop session. He didn't have a console cable, but did have network access to the switch.

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