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New Member

Where do you start with IOS?


I am very new to Cisco but been a techie in IT for 22 years.

I have had a poke around this site for over a week...

Where is the 'Getting started with Cisco IOS'?

I now know that SDM doesn't work, so I have to go CLI.

Where is the basic stuff? How does the CLI work? What does write memory do? What does copy runn startup do? What is a ciper and how do I set one up for WPA-PSK? How to get PPTP passthrough working? Where is FTP-ALG and SIP-ALG? Why does inspect SIP increase latency to 3000ms?

All I've found is docs full of TLAs that I don't think I need.

I have bought an 800 series but have no idea where to start. A good place would be a dictionary.

e.g. guest-mode = broadcast SSID

After 3 different routers (I thought they must be faulty!) and 7 very long days of trying to get basic functionality, I have just done a factory reset to start over. I can't work out how I ever got it to work at all.

If there's a bit of this site I haven't found yet, please direct me there...



New Member

Re: Where do you start with IOS?

Hi, I raad your post and getting started with CLI is not that hard. Write memory will save any changes you made to the configuration, if you make changes and have a bad result you can reboot your device and the changes will be gone if you didn't do a write memory. copy run start-up will copy the running config to the start-up config. when you make changes on your device they are stored in the running config untill you do a wr mem or a copy run start-up. have a look at the document below it should get you started. HTH

Hall of Fame Super Blue

Re: Where do you start with IOS?

Hi David

Firstly the questions you are asking are covering a lot of different subjects and therefore you are unlikely to get a complete answer. So the best way to start is to get the basics running on your router first.

Cisco's website is one of the best web sites i have come across for technical documentation. There will be a document somewhere that answers whatever question you have but it can be like searching for a needle in a haystack at times !

So in addition to the previous links posted here is one more

This is for configuration of the 800 series routers. There are full configuration guides and also configuration examples for particular bits. The config guides are a good place to start.

And then of course there is NetPro where you will find many very experienced people who have probably already done what you are trying to do and they will be only too happy to help. If you start with the config guides, see how far you get and as and when you come across problems feel free to post to these forums.



New Member

Re: Where do you start with IOS?

These all seem to either be too low level or far too high a level for me to understand. (I have set up loads of other manufacturers' routers with ease)

What I really need is a quick start guide.

1. Set up LAN

2. Set up xDSL

3. Set up WLAN

4. Set up NAT port forwarding

5. Configure the firewall

6. Upgrade firmware (I have the file!)

7. Set up QoS for IP telephony

I managed 1,2 & 3 by trial and error but it took 140 man hours!!!

Tried 4 but nothing gets forwarded, tried 5 but the router is wide open. Haven't attempted 7 as it involves a firmware upgrade.

New Member

Re: Where do you start with IOS?


I just typed NAT Port forwarding in the search engine and ended up with this,

as the result. which I believe will answer problems 4 and 5. The problem you may have is there are so many options. you'll have to trawl through to find a fit for what you want to do.

Finding stuff on upgrading the software wasn't quite as easy. wasn't so much a search result just a bit of poke about on the support pages.

just select ios the version your going to and you should be able to get instructions on what to do to update the software.

follow this URL for QoS

I hope this helps. There are a lot of options. If I were setting the router up I would ugrade the software first. Sometimes (extremely rarely) commands from previous versions of software are not carried through to the next version, for whatever reason. It would be really very annoying to set up your nat and firewall to find that the next version of software doesn't implement it the same way.

anyway good luck


New Member

Re: Where do you start with IOS?

Hi Tony,

Thanks for the reply... I'd already been to all those places and none of it seems to make any sense or doesn't work... I can't find anything on that just does the basics from scratch. (22 years in IT hardly makes me a newbie though)

The upgrade of firmware says:

%Error copying scp://davidraw@ (Not enough space on device)

I have now spent 140 man hours on the 877W and still can't get it to do the basics. The last thing I tried actually killed the LAN side (I never even knew that could actually be done!).

I just don't know how a company can sell a simple appliance that needs such a knowledge of obtuse syntax to even do the basics and then not offer the documentation to go with it.

My last chance is a book from Amazon, I guess.

I'm really at my wits end, I don't know how to go forward with this. Looks like the 877W could actually become a really expensive doorstop.


New Member

Re: Where do you start with IOS?


The message says there isn't enough space on the router to take the file your trying to load.

The router stores the IOS in flash, so you need to upgrade your flash memory.

There are other options such as configuring your router to load IOS from a tftp server,

boot system {rcp | tftp | ftp} filename [ip-address]

Flash should be fairly simple to upgrade. But if your really need the new version of sw and your a bit stuck which it seems you are then this could be a quick option.

As for the rest. Cisco are a pretty big in this whole router thing. I've mostly found the documentation to be pretty easy to find once you figure out what the cisco term for it is..... maybe thats the problem your having?


New Member

Re: Where do you start with IOS?

Hi Tony,


e.g. guest-mode = broadcast SSID.

I stumbled on that completely by accident.

A dictionary would be a good start :-)

Can I delete the old flash to make room for the new one? Was I mis-sold this router for this upgrade as they were bought in the same transaction? (There is no way that I will run an FTP server just to look after a router!)

New Member

Re: Where do you start with IOS?


Not sure about deleteing flash to load a new one. From my experience, the router checks the file to check it will fit on prior to allowing it to be put on the flash. Must be doing that through the MD5 or something... Thats just me conjecturing about whats happening.

I would talk to the VAR about your problem give them the same error codes, hopefully they come back with a simular answer to the one I gave and act on it from there.

As far as cisco speak for stuff, I'm sure a few google searches may help though the search engine here is powered by google, they may only looking at not the whole planet.

Good luck.


New Member

Re: Where do you start with IOS?


another quick hint for CLI, use "?" alot it gives a list of available commands from where ever you are.


New Member

Re: Where do you start with IOS?

Thanks Tony,

I think it's the concepts of *how* Cisco routers work is what I need.

A quick doc explaining how and in what order packets get processed at each interface would help me understand at what stage each bit of the config kicks in.

(A bit like the way phone calls get processed by Asterisk configs)

E.g., an incoming packet arrives at Dialer, goes to ATM, gets processed by ACLs, gets inspected by SPI, gets translated by NAT, gets forwarded to BVI or Dot11Radio, gets processed by more ACLs, gets inspected by another SPI and routed to the internal computer (I have no idea if any of that's even remotely right).

The internal computer responds and some kind of return journey for a related packet is initiated. But what happens to the packet on the way?

(Actually starting with traffic going from an internal computer to the Internet would make more sense)

Some kind logging with the ability to actually watch what's happening in real time would be helpful.

I think this is where I am getting lost and without an overview of how traffic travels, I will never be able to configure the thing except by trial and error.

Actual examples with explanations always concrete the thoery.

Knowing what commands there are in the CLI only makes sense if you know what they are there for...