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Posted on in Programming
Sometimes it seems like a great idea to receive updates whenever someone commits something to your Subversion repository, right? This has definitely seemed like a good idea to me, but it's only nice if you work in a small shop with only a few developers. Too many developers make this …
Posted on in Software
Somehow I managed to miss the fact that Mac OS Forge released MacPorts v1.5. If you aren't familiar with MacPorts, it's the reincarnation of DarwinPorts under the Mac OS Forge / Apple banner. For any UNIX admin, or serious OS X-er, MacPorts is an extensive collection of UNIX tools ported …
Posted on in Networking
Use Cisco ip helper-address deliberately: verify the default UDP broadcasts it forwards, keep DHCP working, and restrict only the protocols your topology does not need.
Posted on in Software
Anyone that has spent any time with Best Practical's RT: Request Tracker knows that it is a leader in the open-source ticketing system market. It is both robust and highly configurable. I've used several systems for incident, trouble, and bug tracking over the last 10+ years, but RT is by …
Posted on in Networking
This isn't late breaking information, but there's an interesting post in the Cisco WAN, Routing and Switching Forum regarding a particular regular expression that, when used in conjunction with the show ip bgp regexp, results in a router crash. Here is the full command.
show ip bgp regexp (.*)(_\1 …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
When a Cisco switch or router reports a power problem, start by finding out whether the issue is input power, a failed supply, redundancy, PoE budget, or a sensor alarm. Those are related, but they are not the same failure.
For most Cisco IOS and IOS XE platforms, this is …
