# Cisco help needed, 1900 series switch connectivity problem



## Fitseries3 (Dec 21, 2011)

i got some cisco gear donated to me today and im trying to test some of this stuff out. 

im trying to telnet in to this catalyst 1900 series lan switch. model is 1924A

i cannot get into the switch from telnet or browser. i have read the setup manual from cisco's site but still cannot get into the switch. 

any help would be great. im no newb here though... this one's just being difficult.


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## theJesus (Dec 21, 2011)

I'm a bit rusty, but I'll try to help anyways.  How are you physically connected to it?


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## Fitseries3 (Dec 21, 2011)

eth from laptop to switch


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## theJesus (Dec 21, 2011)

To what port?  Also, what exactly happens when you try to get in?


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## Fitseries3 (Dec 21, 2011)

this may help...







THEN you can access it from firefox BUT you have to have the IP address to do that. 

IF it already has an IP set... how would i figure out what it was?

it uses standard telnet port, but i have no idea what address


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## theJesus (Dec 21, 2011)

Do you have a rollover cable to just connect to the console port? (assuming you even have a serial connection on any of your machines)


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## Fitseries3 (Dec 21, 2011)

no serial. it says i can use the management port but they say you need a special cable. im looking to see if maybe i can fab one up if i find the right pinout.


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## Fitseries3 (Dec 21, 2011)

shit... guess theres no way without serial


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## theJesus (Dec 21, 2011)

Yeah that's the rollover cable I was talking about.  It's RJ-45 on the end that goes into the console port and serial on the end that goes into your computer.

Do you know the MAC address of the interface you're connected to so you can do an inverse ARP request or whatever?


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## Munki (Dec 21, 2011)

Take a rollover cable from your NIC to the console port on the switch.
Download pUtty http://filehippo.com/download_putty/download/1215879991e60726c2b3a41c02b32f0e/
In putty select your NIC as your connection.
You should be able to get to the CLI.
You need to make sure that the config is clear.

You can do this by going into global config mode and typing delete vlan.dat (Command may vary from iOS version. Use the ? to help you if needed) then type delete startup-config.
then back all the way out of the switch and when you try to come back in it will reload itself with a clean image(for the most part).


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## Frick (Dec 21, 2011)

Aye, you have to connect to it directly first. I guess you could use netstat to figure the adress, if it has any, but if it's passworded and stuff you still have to reset the machine and make the configs directly. It's not even sure Telnet is enabled on it.

EDIT: And what Munki said.


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## theJesus (Dec 21, 2011)

Nifty, I didn't know you could connect a rollover cable to your NIC, I thought it had to be serial.  Anyways, I found a pic for you Fits, so you can make your own (also shows why it's called a rollover lol):


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## Fitseries3 (Dec 21, 2011)

theJesus said:


> Yeah that's the rollover cable I was talking about.  It's RJ-45 on the end that goes into the console port and serial on the end that goes into your computer.
> 
> Do you know the MAC address of the interface you're connected to so you can do an inverse ARP request or whatever?



i have the mac address yes.

do i need the serial adapter or no?


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## theJesus (Dec 21, 2011)

Fitseries3 said:


> i have the mac address yes.


Then you should be able to do an inverse ARP request to get the IP.  I think you'd be better off making the rollover cable and connecting to the console port though.

edit:  Munki said connect to your nic, so I assume that means you don't need serial.  I didn't know that, but I also don't have real-world cisco experience.


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## Munki (Dec 21, 2011)

You don't need an adapter.

If you try to do a reverse arp most likely its going to fail. Each port is a broadcast domain, which means you have an individual address for each port.


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## Fitseries3 (Dec 21, 2011)

i found this... http://www.cisco.com/en/US/tech/tk175/tk15/technologies_configuration_example09186a0080093e33.shtml

but perhaps it would be easier to make a rollover cable since i have no serials around here.


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## theJesus (Dec 21, 2011)

Yeah, do RJ-45 on both ends like the diagram I posted, that'll be a lot easier.

edit:  Better diagram


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## Fitseries3 (Dec 21, 2011)

was a bitch to hand wire.. couldnt find my crimper tool.


now what? lol


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## theJesus (Dec 21, 2011)

Follow Munki's instructions.


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## Fitseries3 (Dec 21, 2011)

Munki said:


> Take a rollover cable from your NIC to the console port on the switch.
> Download pUtty http://filehippo.com/download_putty/download/1215879991e60726c2b3a41c02b32f0e/
> In putty select your NIC as your connection.
> You should be able to get to the CLI.
> ...



putty wont let me not enter an ip address. i cant get to terminal


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## Fitseries3 (Dec 21, 2011)

hmmm.... 






not working


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## theJesus (Dec 21, 2011)

Hmm, I think maybe it does have to be serial then.  I can't find any info online about connecting without it.


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## Fitseries3 (Dec 21, 2011)

now if i could just figure this out....


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## theJesus (Dec 21, 2011)

I thought the serial ports on a PC were 9-pin?

At least, they are on all my boards lol


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## Fitseries3 (Dec 21, 2011)

nah... this is so i can connect from PC's ethernet port to cisco's DB-15 AUI management port on the switch


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## theJesus (Dec 21, 2011)

Oh, I was thinking of the switches with RJ-45 console ports.  Either way, I think you need to go into the serial port on the PC.


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## Munki (Dec 21, 2011)

I was wrong, you do need a converter. Im use to luxury of it being punched down at work lol. 1900 model switches should have a RJ-45 look on the back of the switch


EDIT: Nevermind im thinking of another model. No you do have an AUI  

IDK, if you can get into the CLI you'd have this fixed lol


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## theJesus (Dec 21, 2011)

I just looked at some pics of the 1900 series, there should be an RJ-45 labeled "console" on the back.  You need to go from that to the serial port on a PC.


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## Fitseries3 (Dec 21, 2011)

this one has both AUI and "console" labeled ethernet ports. 

i found that diagram on how pinout is on the AUI to RJ45 cable  but its not working for some reason. 

i guess i'll have to find the RJ45 to serial setup and a pc to use it with. all i have is my laptop and its only got usb


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## theJesus (Dec 21, 2011)

I hope you've got enough old parts laying around to put something together with a serial port


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## Munki (Dec 21, 2011)

Dang, I was right and then right again in the wrong sense. lol. Man late nights aren't being nice to me.


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## theJesus (Dec 21, 2011)

Take a look at these:

This shows how the pins are numbered on each connector





And this shows which pin on one end corresponds to which pin on the other end






edit:  Do note that the top diagram is showing the female RJ-45 port on an adapter, so when you're looking at the male RJ-45 plug (clip on top, facing you), it'll be reversed. ie: count up from left to right

edit2:  Also, I could be entirely wrong about how to interpret that table, so uhh, good luck?  I'm going to sleep now.


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## Fitseries3 (Dec 21, 2011)

how would i go about InARP'ing to figure this out?


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## Fitseries3 (Dec 21, 2011)

well some progress has been made. 

i used spiceworks to figure out the ip addy

i can connect via telnet or firefox but i am stuck at the password prompt. i've tried about 100 common ones and its still a no go.


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## Munki (Dec 21, 2011)

http://www.cisco.com/en/US/products...ducts_password_recovery09186a00800a6c79.shtml

See if this helps


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## Fitseries3 (Dec 23, 2011)

happen to have a spare cisco console cable laying around?

seems there is no way into this cisco stuff without the cable


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## theJesus (Dec 23, 2011)

I don't have any 

edit:  Even if you have it over-nighted from somewhere, you're probably not gonna be able to get it 'til Tuesday.  Monday if you're lucky.


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