Posts tagged networking
The Importance Of Change Management And Record Keeping
Oct 14th
For the past two months something has been going on with our firewall at the office.
I use JFFNMS to monitor my network and I began receiving notifications that certain services and ports on the firewall were randomly closing and opening. I tried to see what was going on, but nothing turned up in the event logs. It would happen once or twice a day, but none of the users ever mentioned the services not being available or having trouble accessing the Internet, so I didn’t make much of it.
Beginning about two weeks ago it started happening more and more often, and this time the firewall was crashing every 3-4 days. When the server would crash everyone would lose external email and Internet access, so this clearly was not an acceptable situation. I tried some suggested fixes, including updating the NIC drivers but nothing worked. The machine would run out of resources, eventually lock up and need to be hard booted. I had decided it was probably time to call Microsoft to find out what was going on.
Before I laid out the $270 for a support call I needed to do some research into when this problem really started (and MS was probably going to ask me for that information anyway.) I looked back through my email archive to see when I started receiving the failure notifications. I had been focusing only on the past two weeks when the machine started crashing and not remembering that the problem actually started much earlier.
Now comes the important part. I used that information to look through the log I keep of server and network changes and maintenance. It turns out that two months ago I made a change to the firewall rules, and the problem started the very next day. It was hard to see how this particular change would cause the machine to crash, but it was too coincidental, so I disabled that rule and restarted the firewall service. There have been no warnings, problems or crashes since.
I hope you can see the value of good record keeping. If you are making changes to your network without keeping a detailed record of what you are doing and when you’re doing it, it is going to be extremely difficult to diagnose problems later.
You can keep the log any way that works for you, just be sure you are keeping something. I used to keep it manually in an actual notebook, but I later switched to using a blog. That just made it easier to have everything logged by date. Then I categorize the posts so it’s easy to find all the entries about my Exchange server or firewall. If you keep the log electronically, you would be wise to keep it someplace other than on a file server on your network. If you can’t get into the network or server because of a problem, you don’t want
to also be kept from accessing the change log which might help you fix it.
Geeky details: What I think was really happening was that the rule I changed blocked access to some domains I didn’t want people accessing. These domains were still sending us email, or more accurately; spam, but the return emails/NDRs were being blocked. The firewall rule also was set to create a log entry when the rule fired. As the volume of incoming emails increased, the system couldn’t keep up with the logging of the return failed emails and the firewall was configured to shut down the firewall service if logging failed too many times in a row. So once I turned off logging for that rule, everything went back to normal.
So let that be a lesson to you too. Unless you’re running a real high-security system, don’t let a logging failure bring down the server. Logs are important, but not usually not more important than uptime.
I need to open a port on my router or firewall. How do i do that? What is that? Should I Be Scared??
Jan 20th
Almost 3 weeks in to the New Year and the Admin needs some rest – maybe a day off?
Yeah right we have even more emails today and I am studying for my 2008 Microsoft Certs! This has been a big year for the AtA gang – stay tuned for more of our geeky flavored content in 2008.
Our reader Diego has an application on his computer that he needs to get access to while he is away. Diego is trying to get VNC going on his iPhone. This tutorial is for you no matter what router you are on but, it uses the WRT54G as an example. You should be able to use the knowledge to work with most modern routers. To begin there are a few things you need to do. First as a prerequisite you need to know the difference between external and internal ip addresses.
You see that you can’t get to your internal addresses also referred to as your NAT IP from outside without some work. You are in a protected kingdom. (Pardon the corny references but they work well!) The inside of your network is like the inside of your virtual castle.
The only way in is by opening a port sort of like building a virtual draw bridge. To open this draw bridge to your computer over the internet you need your computer to have a static IP address.
Now we need to see if you are using a static IP or a dynamic IP. Do you know how to tell? In Windows this is done by:
- Right click on the my network icon
- Choose properties
- Right click on the icon that represents your Connection
- Choose properties.
- Scroll down to Internet Protocol and click Properties.
- If the check box is checked to obtain an IP address automatically then We want to check the Use The IP address. BUT don’t fill in anything or click OK yet We will get right back to this as soon as we get the address to fill in!
- Now we want to goto DOS and find your current IP address. Goto Start
- Run
- Type in CMD and hit enter
- Now type ipconfig /all
- and write down your IP address, subnet mask, default gateway and DNS servers. We Will now fill this address information into the address box we left blank a moment ago.
- Now you have a static IP address and are half way there! Now go to this link here:
Plug in your static IP we set above and follow the rest of the instructions and you will be remote controlling your PC from your Shiny iPhone in no time! Let us know how it works out for you!
PC power users switching to Mac? Mac’s got a toolbox that’s right up your alley!
Dec 24th
HAPPY HOLIDAYS kiddies,
Comodore64 back again to shed some light for any newly ordained Mac users that are carrying over from the M$ world. Since Mac is gaining a kind of strangle hold on the industry, I’m pretty sure there are a lot of guys like myself who have a PC for certain purposes and a Mac for others. In my case, it’s a Powerbook. But not just any Powerbook, this is one of the last Powerbooks made with a PowerPC processor, right before Jobs and Co. made the switch to Intel processors. In retrospect, it was one of my better purchases in life. Worth every penny, and keeps on tickin. Unfortunately, a lot of you didn’t stay on the PowerPC bandwagon, and jumped over (maybe not even by choice) to the new Intel Macs. From what I’ve seen and heard , they are quite the problematic little buggers. But my PowerPC Powerbook has been rock solid since day 1 (gleam.)
Shortly after buying this Powerbook over 2 years ago, I was rummaging around the hard drive for whatever pre-installed goodness I can come across a folder that looks like the image above. This collection of proggies is sure to make any former M$ user feel right at home.
Here is a rundown I’ve found courtesy of http://www.freemacblog.com/exploring-the-utilities-folder-on-your-mac/
Activity Monitor – Activity Monitor let’s you know what is going on with your computer. It can let you know where your memory and CPU is being used most.
Airport Admin Utility – The application will let you configure your Apple Airport products.
Airport Setup Assistant – This app is used when you first set up your Airport product. It’s an easy wizard for setup.
Audio MIDI Setup - You can use Audio MIDI Setup to configure the audio input and output devices you use with your computer, such as microphones and audio playback equipment. If you need this app, you probably already know how to use it.
Bluetooth File Exchange – If you have a cell phone or PDA with bluetooth, this application makes it very easy to send files back and forth. This is a great way to take your photos off of your phone, or to add ringtones to your phone.
Colorsync Utility – This app gives you access to to Apple’s Colorsync specs. In this app you can set different profiles. There is also a nifty calculator that can convert between RGB and CMYK. This is another of those apps that isn’t useful to most people.
Console – Console gives you a “behind the scenes” look at your Mac. While you see all the pretty pictures and graphics of Mac OS X, there is a ton happening in the background. Console lets you watch that. It’s especially helpful to see error or status messages.
Digitalcolor Meter – If you are preparing your work for professional printing and you have an Apple monitor, you can use DigitalColor Meter to match the color on your screen against several industry standards.
Directory Access – Directory Access lists the different kinds of services that Mac OS X can access. The list includes directory services, which give Mac OS X access to user information and other administrative data stored in directory domains. The list also includes kinds of network services that Mac OS X can discover on the network.
You can enable or disable access to each kind of service. If you disable a kind of service in Directory Access, Mac OS X no longer accesses services of the disabled kind. The different services can be found here.
Disk Utility – There is all kinds of power in the Disk Utility. Here you can reformat a disk, check and fix permissions, and so many other things.
Grab – Grab will let you “grab” screenshots of your Mac. Of course, you can already do this with key combinations, but Grab does have one nice feature. You can do a timed grab. Start the timer and ten second later the Mac will grab a screenshot.
Grapher – Grapher lets you create 2D and 3D graphs from equations.
OS 9 came with a graphing calculator. OS X versions before Tiger had no graphing options. But, with Mac OS X Tiger, we now have Grapher.
Installer – You’ve probably used Installer a hundred times and didn’t know it. Whenever you download a new application that comes in a package or a metapackage, Installer makes it possible to install that application.
Keychain Access – Keychain Access gives you access to the keychain. Duh.
Anytime you save a password to a site or a server or anything on the Mac, it is stored in the keychain. If you forget one of those passwords and it isn’t filling in automatically, you can access keychain with this application and find your password.
Migration Assistant – This is simply one of the most amazing applications. If you’ve ever purchased a new Mac and migrated from your old one, this is the app you used. You can also use it to get a use from a different machine.
Netinfo Manager – Netinfo is the built-in Mac OS X directory system. It stores information about users and resources and makes it available to Mac OS X processes that want to use it. This application helps you manage it.
Network Utility – Since I run a fairly large network of Macs this app is great. It makes it easy to ping machines, lookup name server and DNS, do traceroutes, port scans, etc. It also is a quick way to find info on your Network interfaces. (e.g., ethernet, airport, etc)
ODBC Administrtator – This will give you access to database management systems using Open Database Connectivity standards.
Printer Setup Utility – When you get that new printer and hook it to your Mac, this app comes to the rescue. It will lead you along to get the printer working.
System Profiler – If you need information about your Mac, here is the place to come. It will tell you about your RAM and your drives and your processors and anything thing else you’d need.
Terminal – This is the gateway to the true power of Mac OS X. It is a terminal emulator that will let you use the Unix base of Mac OS X.
VoiceOver Utility - Voiceover is a Mac OS X feature that lets you interact with your Mac via voice. It will read the text of websites, email, and documents. It also allows you to control your Mac using audible commands. Voiceover Utility lets you determine how Voiceover will behave.
Well, kiddies I hope this helps you settle into your new Mac a little easier. Some of these Utilities are clutch and definitely make me feel more in control of my MAC.
Til next time,
Commodore64 (The one you used to play Bruce Lee on)
Amazon is Down! – No redundancy while the shopping giant suffers a major outage
Jun 6th
That’s right kiddies!
Ask The Admin brought it to you first. Don’t go knocking on Amazon’s door today. Nobody will answer.
Could it be that the Shopping GIANT of the net doesn’t even have server redundancy worked out right for itself?
Anybody out there know anything about this? Doesn’t Amazon offer hosting services as well?
Hit us in the comments people. Any speculations? DOS Attack?
You tell us…
Hit the comments, aaaaaaand begin!
(Edit they are back up at 3:05pm… Maybe all the Admin’s were out to lunch? Almost an hour down that has to cost some serious moolah!)
(Double Edit: 3:14 back down again…)
3:32 When you can get to the site we have a pretty little note posted…
And now Rumors are flying that it is PS3 related here and here… Anyone?
C64 (the one you used to play Bruce Lee on)
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