Preserved Topic: Hardcore Unix Question... (Page 1 of 1)

I probably will have to seek out a Unix forum for this one, but does anyone know about modifying Network Address Translation tables?

Specifically for use with a Cisco 678 DSL modem, I want to know how to determine what port number a given process uses (ie. web server, Napster, Hotline server, etc.), and how to add entries into the Cisco's NAT table. I have Mac OS X, so presumably there is some CLI utility i can use to accomplish this already installed in Mac OS X, or at least easily portable.

I have searched around the net already for this, but does anyone know a good resource offhand?

-jiblet

I do not know how to do this, but I do think I know the person who would. That would be Pugzly... If you talk to him I am sure he could either point you in the correct direction or give you the info off the top of his head. Of course he will charge you a tutorial for the gurusnetwork for any help he does give to you.

p.s. pat(.nospam.)@runningwolf.com



[This message has been edited by WarMage (edited 05-11-2001).]

You win the prize for deceptive topic description of the day.

You're really asking three things.
1) How to determine what port number a service uses.
The well known ports are defined in RFC1700 which you can get here and other places. Napster and newer things won't necessarily be listed. Since you're running OS X, try netstat -a to see a list of open ports on your machine. Also see if you have the file /etc/services, which should resemble the RFC strongly, but also have newer things like ssh listed.

2) how do I configure a Cisco router?
You telnet to the IP address of any of it's interfaces, and provide a password. Then you give the enable command to enter privileged mode. Then you give the configure terminal command to enter config mode. Then you do your thing.

If you don't have those passwords, it gets much more fun. You'll have to do password recovery, which is specific to your hardware.

3) How do I add to the NAT groups defined on my router?
The basic commands are all ip nat commands. Since you're also asking about ports, you probably are doing PAT (NAT overloading). This document from Cisco splains it much better than I probably could, so.... http://www.cisco.com/warp/public/cc/pd/iosw/ioft/iofwft/prodlit/iosnt_qp.htm

If you want help, send me a copy of your config (show running-config) with a description of the changes you want by email.

Deceiving maybe, but apparently it got the right guy in here. Thanks so much, that is very helpful. I've been piecing together bits of information gleaned from cisco tech docs and other things I've found, but your information is tying it all together. I should be able to get it configured relatively easily now.

Afterwords I may write a tutorial for newbies since this seems like a common problem that can occur for DSL users with multiple computers, and I found no material that really addressed this problem from a consumer standpoint.

-jiblet

Good thing I'm a Unix weenie and Cisco certified

Hey, how do you like OS X? I understand it's based on FreeBSD, which I have extensive experience with.



[This message has been edited by linear (edited 05-11-2001).]

Well I only have 128 megs of RAM, which is the min. requirement, and it is woefully inadequate for normal system use. I think if I pop another 256 in there it should speed things up significantly.

As far as the system goes, I am very excited about the future possibilities, the graphics engine is slick, and Darwin serves my limited Unix needs extremely well. So far OS 9 is much more practical for getting work done, although I have already found OS X to be far superior for Java development (even though Java Applet support is horribly inadequate in all OS X browsers).

As a web developer, it's nice to be able to run Apache out of the box, and with pre-compiled binaries and easy tutorials for installing PHP and MySQL, internal back-end program testing has never been easier. It's very nice to be able to simply save the file and reload in the web browser without having to constantly re-upload and wait for the page to reload (particularly if your web host isn't your ISP).

I give Mac OS X a year before it can serve the needs of a serious Mac Designer/Graphic Artist. From the unix geeks I have heard such varied information I really couldn't say if it is functional enough for a hardcore hacker. I will say that I am extremely excited about the ramifications of combining a BSD with a consumer OS. I think being able to hack on a box that still contains all your old adobe stand-bys is really going to be a breakthrough for the open-source community, allowing people to use one OS for all their computing needs is certainly going to push me towards unix development.

My biggest complaint is the necessity of endless eye-candy. They need to offer a speedy mode where all the animation and translucency gets disabled. Maybe it will be fast enough on my G4 when I upgrade the RAM, and while what it can do graphics-wise is impressive, ultimately speed is more important.



-jiblet

Hey jiblet, one more thing--don't forget to copy running-config startup-config when you've made your changes, or next time you bounce the router, you wan't have your changes in effect.

I am holding off on doing this until my roommate fixes his PC. The Cisco software is PC-only and Windows recently crashed and burned on his computer, so I don't wanna run the risk of screwing anything up on the modem without the software to reconfigure it.

BTW, 'configure terminal' was not a valid command after enabling, and there was no 'running-config' to show, the closest thing I saw was the NAT table. I'll probably get back to u on this one when I'm ready to try again.

-jiblet

Those are IOS commands, sounds like you're using the GUI whose name I can't remember cause I don't ever use it. If you telnet to the device, those are good IOS commands.

Nope, I telnetted in.

-jiblet