Hi and welcome to this CertificationKits CCNA training video on viewing and managing the router configuration files as well as the IOS. We are going to be talking about the difference between the startup configuration and the running configuration and how we can tell our router to ignore the startup configuration when we boot so the router will come up un-configured basically to factory default settings. Viewing the IOS using a TFTP server which is Trivial File Transfer Protocol to create backups and not only the IOS,but the running and startup configurations as well.  Upgrading our IOS using a TFTP server and then troubleshooting like if our router came up, started to boot, and couldn’t find the IOS.   The types of errors we would get and how we would go ahead and load a new IOS.

We have four main memory areas on the router. We’ve got RAM where we store the running configuration. We have NVRAM where we store the startup configuration. RAM is volatile so if we turn off the router, whatever configuration is in RAM is lost. NVRAM is non volatile and that’s why our startup configuration is there because if we turn off the router, whatever is in there is going to still be there when we reboot and we can use the startup configuration file to configure the router initially when we boot. Running-config and startup-config do not have to match. The third area is ROM; Read Only Memory and we have things like our post routine in there as well as what’s called rommon.  Rommon is kind of like a safe mode for the router. The last one is Flash where we store our IOS in Flash which is our IOS. You can store things there but typically it’s recommended that you just store your IOS in Flash.  Because what happens when the router boots, the first file that sees in Flash, it will go ahead and load that and use that as the operating system. So if we have something else in there and it’s a file before the IOS, then it will try to load that and then the router may not be able to boot. So when we boot up depending on what our configuration register settings are, which we’ll talk about that in a little bit more detail here in a moment; the router will grab the first file that sees in Flash and load it into RAM and have the router up and running as that operating system.

Then we will take the startup configuration file and configure that operating system to have the router up and running. What we’re going to do real quick is take a look at how we can view the running configuration and startup configuration. How we can manipulate those, how we can back it up and how we can save our configuration like our run to our startup config.  So if we go in and configure the router and we like our running configuration and how it’s currently configured; then we can save that to the startup configuration. So if we reboot then our configuration is not lost.

In my CCNA simulator here I’ve got, let’s take a look at the Net Map. I’ve got a router connected to a TFTP server just for basic demonstration.  So I have one router where we can look at the configuration files and then have a TFTP server that we can use to backup the configuration files too. So let’s go in and take a look at this configuration files. Now I’ve gone and configured this router which is called Palestra1. If I want to see the running configuration, that’s how it’s currently configured to run; its configuration is stored in RAM and that’s called running-config.  I can go in and take a look at that. This configuration file will be lost if I reboot the router so I want to makes sure if I like it, I save it. If I want to make sure that the startup configuration is something I like, I can do show startup config.  

If I reboot the router, this is the configuration file that will be used to configure the router and notice something; if I do a show run, interface serial 0 has an IP address on it.  If I do a show start it does not.  So my running configuration and my startup configuration do not match and that’s fine. However, if I like the running configuration that I see in here and I wanted the router to use it when I reboot; maybe I like this IP address on serial zero and then I can go in and save the running configuration. All I have to do, to do that is type copy running-config startup-config and then it will save the running configuration to the startup configuration. So if I do a show start, now I can see that the startup configuration has an IP address on serial-zero.  It’s like saving changes to a word document. What’s nice about this is I can go in and configure the router and I might want to go in and make some changes or I’m trying to troubleshoot.  Like change the IP address on serial 0, whatever I’m just going to change it to 1.2 instead of 1.1.  Mot a big deal, I can do a show run and I can test it out and see if this configuration actually works. If it works, great I’ll save it.  If it doesn’t, all I have to do to get rid of it is do a copy startup-config running-config.  

So what I love about this is I can go in and mess with the router.  It might be having some problems having automatic backup of the configuration. So worst case scenario if I go in and make some changes and they don’t work out very well all I have to do is go copy startup-config running-config and it will copy the startup configuration into the running configuration and reconfigure the router the way it was before I got there. I just want to make sure that the startup-config is a valid file.  I don’t go in there and make changes without saving the current running configuration first to the startup config. So copy startup-config running-config.  It goes in and makes the changes for me.

Now on the CCNA simulator, no guarantees.  So I went in and changed the IP address on the running-config and I changed it to 1.2 and I did copy startup-config and running-config and like its back. So it did work so it didn’t let me down. So 1721711 was the startup configuration and I overwrote the running configuration with that.  So I really like that feature because it’s kind of a safety net. Now maybe just having a backup file in the start configuration is not enough.  Or I really like the configuration or it’s something that I might want to backup.  It’s always important to have backups. What I can do is if I like the running configuration, I’d save it to the startup so I’d go copy running-config startup-config and save it so my running-config and startup-config match. Maybe it’s not enough. What happens if something happens to my router?  Maybe a little fire or bringing a new router in.  Anyway something happens and the startup configuration gets lost or NVRAM becomes corrupt.  

What I can do is I can actually copy my running-config or my startup-config to a TFTP server.  All I have to do is type in copy running config TFTP and hit enter.  Then what I’ll do is we’ll say “Hey, what’s the IP address of the TFTP server?” Now in my Net Map… in my Net Map I have a router connected to a TFTP server. Ethernet 0 on the router connects directly to the Ethernet nic on the TFTP server and the IP address here is 17216.1.2. So what I can do is I can type address or name of remote host, hit enter and what that does is that tells the router the IP address of the TFTP server.  If I can ping the TFTP server, then I’m going to be able to upload a configuration file to it.  Again, normal networking connectivity is required.  Destination file name, I can call it whatever I want.  I call it Palestra1.  Config, hit enter, it goes ahead and copies it up so it’s gone in and copied it up. What’s nice about this is if something does happen to this config; such as you might have a new admin that comes in, messes everything up, who knows?  I can go ahead and as long as I establish basic connectivity with this TFTP server, I can copy it back.  

All I have to do is go copy TFTP running-config. I can even use copy into the startup configuration file if I wanted to and again the same thing. IP address of remote host, what’s the file name, Palestra1, config, and copy it right back over.  It goes ahead and loads it for me and reconfigures the router.  So TFTP server is a great tool for backing up and saving your configurations as a safety net. So for a quick recap on my configuration files.  When I’m using my copy command it’s always copy and then I specify the source of the copying and then I specify the destination. So copy startup-config  running-config would copy a configuration file from NVRAM to RAM. Copy running-config startup-config would copy from RAM to NVRAM. If I had a TFTP server over here, copy startup-config TFTP would copy from NVRAM to the TFTP server and again I could go backwards. Copy TFTP startup-config would configure the startup-config with a file that I had on the TFTP server.  So it’s always copy, the source and then the destination. Let’s take a look at viewing our IOSand upgrading it and manipulating it through the command line on the router.

Let me bring up the router, so I’m Palestra1 again and what I can do is there are a couple important commands here that I can use to view information about my operating system on the router. Show version is a very important command. This command does a couple of things for me. It shows me information about my operation system; what version it is, what hardware platform it’s running, my system up time, how long my system has been up, the image file where it’s grabbing the IOS from; it’s grabbing it from flash, the name of the file is C2600-enterprise 12.1, and then it shows where it’s booted from and all that.  So all the information about my IOS I can get from a show version. It’s very important to not rename these IOS files because the information contained here will tell me certain capabilities my IOS has.  Different operating systems have different capabilities.  Not every operating system for 2600 can fit on this particular router or simulated CCNA router in this instance. It depends on how much non-volatile NVRAM you’ve got available and how much system flash you have available. 

So it’s very important to use a show version and make sure that if you are going to load an operating system on your router and it’s one that’s compatible. I can type in show flash and I can see what is in flash. Again it can hold more than one file in here, but typically you just want IOS. Number one, the number one here is the first file on flash. That’s the file that’s going to get loaded when I boot. C2600-jsmz, here is my version number, dot bin, binary executable, all IOS  files are binary executable.  2600 hardware platform and the JSMZ tell me different capabilities that this IOS has. I can go on Cisco’s website and take a look at the JSMZ and they will tell me what particular capabilities this IOS has.  Maybe I want to be able to do a VPN directly from the router here.  I’m going to have to make sure I have the right IOS version to support that and this is what will give me that information. So show flash is very helpful command.  Now if I wanted to backup this IOS, as sometimes flash becomes corrupt, I can use my copy command. Copy flash TFTP. 

Now on the CCNA simulator, it’s not going to work.  It gives me an error, but on every other router, a real router with access to a TFTP server, you can copy that over. It’s just going to take a little bit of time because it’s a fairly large file to copy through. So copy flash TFTP will save your IOS from flash and put it on a TFTP server. Flash can become corrupt, sometimes, people might go in and accidentally erase flash that had that happens with students who will go in and erase flash so the IOS is gone.  It’s always important to have a backup of this. You can download these files from Cisco’s website, but you have to have access to their support site. Let’s say I downloaded a new IOS from Cisco’s support site that had extra security capabilities or supported BGP.

What I could do is I could put that on the TFTP server and I could type in copy TFTP flash and what would happen is it would ask me where the TFTP server was. What the file name was and I could actually upgrade my operating system easily. So all I do is copy TFTP flash, it will go ahead and load my operating system.  Once it is upgraded I simply type in the reload command and reboot my router. When it comes back up, it will be using that new operating system so it’s very easy to upgrade the operating system using a TFTP server. Now I’ve closed out the CCNA simulator and I brought up and actual router so we can go in and take a look at a couple of things you might need to do for troubleshooting. Troubleshooting is what you do when it’s not working right. Hit enter a couple of times and I get into user mode, privilege mode and let’s take a look at this router real quick and then there’s show running config.  I can go in and I see I’ve set the name, the password on it and I’ve configured IP addresses on Ethernet and the serial interfaces.

As a CCNA what I’m going to do is I want to make sure that this configuration is saved. If I do a show startup-config, I can see that non-volatile configuration memory is not present. It doesn’t mean that NVRAM is gone. All it means is that I have not saved anything into NVRAM.  So what’s my command? Copy running-config startup-config will go ahead and save my current configuration to the startup config.  Now what that means is when I reboot my router, the configuration that they‘ve got right now, that I’ve gone ahead and saved should come up and configure the router. The router should use that to actually configure the router and it could come up operational as opposed to coming up with no configuration and not operational. So let me go ahead and reboot this router and let’s see what happens. I type reload, confirmed to reload and we’ll go ahead and reboot the router. Now what should happen is it should grab the first file that sees in flash; load it as the IOS  and then go in and us the startup configuration to configure the IOS so my router is operational.

Now I’ve jumped ahead a bit. The router booted here. So what happens was the router came up and I get this system configuration dialogue and it says “Would you like to enter initial configuration dialogue?” What that tells me is the router is not configured. So the configuration file I used or the configuration file I saved that was in RAM and saved it to NVRAM, it was not used to configure the router. So I never really like entering this initial configuration dialogue. So I’m going to go in and say no to that and now I’m going to check out my router and find out what the problem is. The first thing I want to do is make sure that my startup configuration file is still there. Show startup-config and I can see that host name Palestra1, my password is there, IPs are there, everything is set up but why isn’t my router configured to that?  The configuration register number, which I go into more detail in another CCNA video, has told my router not to configure itself.  

Let’s take a look at what the configuration number is.  Show version command again, that’s the command I use to check out the IOS in flash and see what was there. Show version, it will also show me my configuration register number and it says right now “My configuration register is 0X2142” and obviously that’s not what we want because the router came up and did not configure itself so let’s look at the proper configuration register number. Let me bring up a previous CCNA slide and here we can see the configuration register. That’s what that says right there, configuration register. I have two of them. The only difference is that’s a four and that’s a zero. Right now, the current configuration register is 0X2142 and 0X2102 is the default configuration register. What this four does is it says ignore what’s an NVRAM when you are booting up. The two here, the boot field says “Hey, take that IOS , take it from flash, put it into RAM and go ahead and run it.” Some routers will run the IOS directly from flash if they have enough flash to store a fully decompressed IOS. Some routers will run it directly from flash.  Others will take it decompress it into ram. So the first file in flash just uses the IOS . The four here says “Go ahead and boot but that startup configuration file, I want you to ignore it” and the router will come out with all its default settings.

The startup configuration file is still in NVRAM. It’s just not used. I’ve seen this before, people will have a configuration register of 0X2142, they lose power to their system or power to their router, the router turns backs on, it boots in everything, but the configuration file is not loaded. So what happens is the router comes up and it’s not working and no one can get out. When you are done working on the system, you always want to get the configuration file back to its default of 0X2102.  So that way if the router does get powered down for some reason, flash will get loaded, the startup configuration file and NVRAM will go ahead and get moved in the RAM to configure the router and have it up and operational.

So let’s go in and see as a CCNA how we can change this configuration register back as well as look what I can do to load the startup configuration file without having to reboot the router. By bringing the router back up with hyperterminal, so the configuration register again is 0X2142.  I don’t like it because my router came up un-configured so I want to change it.  The first thing is no one can get out right now because my router is not configured so I have to go ahead and copy the startup configuration file to the running configuration file and what that does is it takes this as the source, puts this as a destination, it configures my router with that startup-config. So copy startup-config, running-config, enter, and watch what happens to my router’s host name.  It changes from router to Palestra1.

Now if I go in and take a look at the run, show run, I can see that the running-config and the startup-config match except for one thing. If I do a show start again, I can see that my interface is I have IP addressed but it doesn’t tell the router to have the interface to shut down. If you bring the router up and it’s not using the configuration file, it’s not using the startup configuration file and I do a copy startup-config running-config to configure the router. It configures the router with everything but it does not turn the interface on.  If I do a show run and I look at my interfaces, they are shut down. Shut down is not good as it still can’t communicate.  So if you do happen to boot a router and it doesn’t use a startup configuration file and you go ahead and load it; you are going to have to go into the interfaces and turn those interfaces on then you will almost be done. To avoid this problem from happening in the future, what you are going to want to do is change the configurations register from 0X2142 to 0X2102 which is the default. So show version, I’ll just type show ver, that’s a little bit easier for me. Show version, configuration register is 0X2142, I want to change it, get in the global mode, config-register, 0X2102, hit enter, I always verify my work, show version, again to makes sure that it took it and it says configuration register is 0X2142 will be 2102 and next reload. So what that means is if I reload my router right now, it will go ahead, boot up, grab the IOS in flash and since this is a 0 now, it will go ahead and take the startup configuration file from NVRAM, loaded into the RAM, configure my router.

Let’s see what happens. Reload, yes. It asked me if I want to save my configuration, it’s already been saved but it can’t hurt to save it again and what that’s doing is saving running-config to startup-config and I hit confirm to reload and now my router is going to reboot. My router has rebooted, I press return to get started and we can see now that instead of saying router which is the default, it is configured, it says Palestra1, enter my password and if I do a show running-config, I can see that my IPs are there. The interface is not shut down. It would say shut down here and it’s not so it came up. Configure with the IPs, configured with everything else in the startup configuration file and the interfaces are up and operational. We have covered up to this point viewing and managing router files, the startup and running configuration, how we ignore the startup configuration when booting and how we use the startup configuration file when we are booting up. Viewing the IOS, using a TFTP server to create backups, how we can upgrade the IOS with the TFTP server very easily and troubleshooting some startup issues you may run into. I hope you have enjoyed this CertificationKits CCNA training video on viewing and managing router files.