CCNA - a few questions about switch

Author

a few questions about switch

worrywarm

2004-02-28, 5:32 pm

Question1:
"if back up and restore configuration files or upgrade the switch, you¡¯ll need to set up IP addressing information on it."

Here is the configuration on 1900 to backup config file
1900# copy nvram tftp:// IP_address_of_TFTP_server/ file_name

why we need an IP address on the switch? I don't see there is a need?

Question2:
on 1900, we use enable password level 1|15 config the user/enable password. How about telnet? If we set an IP address on the switch, do we have to have a password in order to telnet?
I guess on 2950, it should be same to the routers, use line vty 0 15 password.. before we can telnet, right?

I'm confused

someone can help?

Thanks a lot!!!

Kitsune

2004-02-28, 8:15 pm

Question 1: The switch needs an IP address so that the server has a destination address to send the UDP packets to.

Question 2: Uh... not sure! But, I can say this: I saw no questions regarding the 1900, so I wouldn't worry about it too much.

worrywarm

2004-02-28, 8:32 pm

quote:
Originally posted by Kitsune
Question 1: The switch needs an IP address so that the server has a destination address to send the UDP packets to.

You mean when you do
1900# copy tftp:// IP_address_of_TFTP_server/ file_name nvram

it will prompt for the IP address of the switch?? never know about that?!

boyam

2004-02-28, 8:43 pm

quote:
why we need an IP address on the switch? I don't see there is a need?

Its a matter of management. You don't necessarily need an IP address assigned to the switch. You can use In band management or out of band management. In band management means you'll be using snmp to manage the switch, which means you will need an IP address assigned to the swithc. Out of band management means you'll be connecting a console to the switch and managing it from there.

Your other option is to plug up the switch and let it do it's job and deal with mangement on an as needed basis.

quote:
Question2n 1900, we use enable password level 1|15 config the user/enable password. How about telnet? If we set an IP address on the switch, do we have to have a password in order to telnet?
I guess on 2950, it should be same to the routers, use line vty 0 15 password.. before we can telnet, right?

You are correct in your assumption. You will have to set the login and password on the vty's just like you do on a router. Most Cisco catalyst switches now have IOS in them now including the 2950.

Not sure what Kitsune is referring to in regards to the server needing an ip address to send UDP packets too. This is the first time I've heard of such. The switch's duty is to direct traffic at the Data link layer and physical layer. Remeber the basics and build upon them. By the way, a server will work just fine plugged into a switch with no ip address assigned. Again, IP address is mainly for management and device access.

TFTP is part of the IP stack, therefore, you will need an IP Address assigned to the switch to get tftp to work properly. This is how the tftp server communicates with the switch.

Hope this helps.

worrywarm

2004-02-28, 10:21 pm

quote:
Originally posted by boyam
You are correct in your assumption. You will have to set the login and password on the vty's just like you do on a router. Most Cisco catalyst switches now have IOS in them now including the 2950.

how about 1900? how to config vty? that is my final question

TFTP is part of the IP stack, therefore, you will need an IP Address assigned to the switch to get tftp to work properly. This is how the tftp server communicates with the switch. [/B][/QUOTE]
It sounds right, but when you do copy tftp nvram or copy nvram tftp, it doesn't require you fill in the IP of the switch. Are you saying the switch would try to look for the IP automatically??

THanks!!

boyam

2004-02-28, 11:31 pm

Ok, I now know what kitsune was referring to. He was referring to the UDP packets TFTP uses. My apologies Kitsune for not understanding the first go around.

On the 1900, You can manage through a web interface or if you use the console/telnet, you use a Management console. There is a console settings menu option that allows you to set a logon password as well as unsuccessful logon attempts lockout. This switch doesn't use the normal IOS type software.

TFTP assumes you have successfully configured IP on the server and the switch, meaning ip addresses assigned on each. I have never ever used tftp on a device and didn't have an ip address assigned on both ends. This sounds a little crazy saying this and I feel like I'm second guessing myself, but the tftp protocol rides on IP. IP requires addressing and subnet mask, not necessarily default gateway except in routing environments. If you have no ip address on the switch, then how will the tftp server know where to send packets? Your scenerio of the switch asking for an IP address will never happen because the command is issued from the tftp client, the switch. Look at the log of your tftp server, you will see the ip address of the host it is communicating with.

Kitsune

2004-02-29, 9:48 am

quote:
TFTP is part of the IP stack, therefore, you will need an IP Address assigned to the switch to get tftp to work properly. This is how the tftp server communicates with the switch.

That's what I meant. Staying up too late typing does affect one's clarity! Basically, I meant that tftp can't send data to something without a layer 3 address to send it to.

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