Solved: configuration of routers

amansoi_5 · ‎04-11-2007

DEar all,

I need to configure 20-30 1841 routers . I want to copy the configuration in one attempt by connecting all of them in network and assigning IP to LAN port of router instead of doing copy & paste everytime for all routers.

I will make 20 sample files in advance.

Is this possible ?

regds,

aman

Craig Balfour · ‎04-11-2007

Yes, you can configure the routers on the network. You can even use the network (via DHCP) to do the configuration for you.

Take a look at "AutoInstall Using DHCP for LAN Interfaces" (http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121newft/121t/121t5/dt_dhcpa.htm).

Using this method you automate the configuration of your router using DHCP and TFTP. We use this method very successfully for configuring Catalyst switches and it is supported by the Cisco 1841 routers.

Here is more or less how the process goes:

1. Generate a configuration file for each router either manually or using a script.

2. Place the configuration files on a TFTP server.

3. Configure your DHCP server to allocate an IP address, as well as the location of a TFTP server (DHCP option 150) and a configuration file to fetch from the TFTP server (DHCP option 67).

We use the ISC DHCP server (http://www.isc.org) and our configuration for one of our switches on the DHCP server looks like this (Note: if the TFTP server is not specified - as in this case - it is assumed to be the same server as the DHCP server):

host 0018b95e0a01 { ddns-hostname switch-3; ddns-domainname "flintstone.org"; hardware ethernet 00:18:b9:5e:0a:40; filename switch-3; fixed-address 10.2.4.7; }

4. Connect the routers to the network, make sure that don't have any configuration on them (delete startup-config if necessary), reboot the routers and if all is setup properly they should get IP addresses from the DHCP server, and fetch their configuration files from the TFTP server.

5. The final step is to save the configuration, and hopefully you have 30 routers configured in a fraction of the time it would have taken you to configure them manually or to cut and paste their configurations via the console.

View solution in original post

Craig Balfour · ‎04-11-2007

Yes, you can configure the routers on the network. You can even use the network (via DHCP) to do the configuration for you.

Take a look at "AutoInstall Using DHCP for LAN Interfaces" (http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121newft/121t/121t5/dt_dhcpa.htm).

Using this method you automate the configuration of your router using DHCP and TFTP. We use this method very successfully for configuring Catalyst switches and it is supported by the Cisco 1841 routers.

Here is more or less how the process goes:

1. Generate a configuration file for each router either manually or using a script.

2. Place the configuration files on a TFTP server.

3. Configure your DHCP server to allocate an IP address, as well as the location of a TFTP server (DHCP option 150) and a configuration file to fetch from the TFTP server (DHCP option 67).

We use the ISC DHCP server (http://www.isc.org) and our configuration for one of our switches on the DHCP server looks like this (Note: if the TFTP server is not specified - as in this case - it is assumed to be the same server as the DHCP server):

host 0018b95e0a01 { ddns-hostname switch-3; ddns-domainname "flintstone.org"; hardware ethernet 00:18:b9:5e:0a:40; filename switch-3; fixed-address 10.2.4.7; }

4. Connect the routers to the network, make sure that don't have any configuration on them (delete startup-config if necessary), reboot the routers and if all is setup properly they should get IP addresses from the DHCP server, and fetch their configuration files from the TFTP server.

5. The final step is to save the configuration, and hopefully you have 30 routers configured in a fraction of the time it would have taken you to configure them manually or to cut and paste their configurations via the console.

Anders Marius Jorgensen · ‎05-12-2007

Hi!

I have conducted some tftp config trial as well.

Despite if I specify option 67, the router will still try to get network-confg from the tftp server.

It also seems to be the case will looking at the flowchart in the documentation.

Any idear why ?

paolo bevilacqua · ‎05-12-2007

My opinion about preparing routers with dhcp, tftp files, etc, is that is not worth it.

First of all one is already spending time in creating all the configuration files, making them consistent, and handling the unavoidable exceptions.

Then you have to connect serial console, LAN, configure dhcp and whatever other command needed.

At that point, since you are connected already to console, it would probably take less time to just paste the configuration via terminal program, save, and re-pack.

If the router had a mechanism to load configuration as taken out of the box, without need for serial console, it could be worth doing the files via DHCP/TFTP, as it would become totally automatic connecting LAN only.

Unfortunately this is not the case.

In the past (perhaps people still use that) SLARP was used to auto-install router connected to via hdlc or fr links, however this does not work for LAN.

So the nice tool for massive configurations would be some script on the terminal emulator that copies the config without even needing the LAN connected.