Posted on in System Administration
You may run into a case where you are running a name server (perhaps a caching-only name server) that is not allowed to communicate with Internet name servers. The most common case for this is a local caching name server being blocked by a corporate or <acronym title="Internet Service …
Posted on in Networking
Let me start by saying this article is not about server load-balancing. That's a different topic, and I apologize if that's what you were looking for. That said, interface load-balancing is an interesting topic and one that comes up quite frequently.
A time will come when it becomes necessary to …
Posted on in software
By default, MySQL only allows access by the 'root' account from the host running the database server ('localhost'). Often times that's perfectly adequate. There are occasions when you need remote access as the 'root' account, however. In these cases, it's helpful to be aware of one little gotcha when creating …
Posted on in System Administration
Personally, my data isn't so important that I need to keep years of it backed up to tape. Obviously, that isn't always the case in a corporate environment, but luckily that's not a problem for me.
That being said, I do like to have at least a week's worth of …
Posted on in Networking
On most networks, there is a subset of IP addresses assigned to "management" hosts. These hosts might be the workstations of network administrators or monitoring servers. One of the keys to network security is restricting who has access to the device. Generally, we think of access restriction in terms of …
Posted on in Networking
The last thing I want to do when some network administrator leaves my organization is change all the login passwords on the Cisco network devices. (For now, let's just assume the administrator in question didn't know the enable secret.) If you have relatively few machines, it's easy to setup username …
Posted on in Networking
If you followed my recent Cisco Catalyst rate-limiting post, you already know that policing traffic on a Cisco Catalyst switch requires a bit of thought. Mainly, you have to do a bit of calculating to determine the best bucket size for your application. The good news is that achieving the …
Posted on in networking
This is the full text rate limiting example that accompanies my Catalyst rate limiting post. This example was derived on a Cisco Catalyst 2960 and should be ready to copy and paste directly to your device.
mls qos
ip access-list extended ACL_SLAP
permit ip any any
class-map match-all CLASS_SLAP
match …Posted on in networking
If you need to limit the inbound bandwidth of a switch port on a Cisco Catalyst, the key is in the QoS configuration. Rather than going into an depth discussion of QoS and how it works, let's skip that (check out Wikipedia to get started with that) and jump into …
Posted on in networking
Ever so often, you need to check the status of a the power supplies in
Posted on in Networking
If you work on a fairly spread out network (or have remote clients), you might be managing Cisco Catalyst switches that are far, far away. For a long time, I thought the only option was to have someone on site to pre-configure the switch just enough to get it on …
Posted on in Networking
Sending log messages from your Cisco network equipment to a centralized syslog server is a fairly normal activity. Most of the time, this setup works fine and there's no reason to do anything out of the ordinary. Occasionally though, you might need to run a debugging session over an extended …
Posted on in Software
If you've spent any time managing a web site, you are undoubtedly familiar with the dreaded Alexa rankings. It's common knowledge that these numbers are fairly useless since they depend on the end user having the Alexa toolbar installed. Obviously, not everyone has this. To make matters worse, Alexa only …
Posted on in Networking
Anyone who has ever done anything remotely "interesting" with a run-of-the-mill broadband router is undoubtedly familiar with the concept of port forwarding. In the case of some applications (<acronym title="Peer-to-Peer">P2P</acronym> comes immediately to mind, but the <acronym title="Real-time Transport Protocol">RTP</acronym> part of <acronym title …
Posted on in System Administration
I recently installed Microsoft Windows XP Pro in Parallels Desktop on my iMac. After going through the usual motions of updates and tweaks, I set up my user account so that I wouldn't be using the built-in Administrator account. After rebooting the virtual machine, I noticed that on restart, I …
