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Sep 24 / jocke

Cisco IOS NAT Virtual Interface

Up until recently, I’ve had ADSL at home for some years. For the last year or so, I’ve used a Cisco 1812 as my router (the ISP-router was put into bridge-mode). A few weeks ago, when I got a 10/10Mbps fiber-connection, it suddenly became more relevant to host some services at home (why pay for web-hosting, when you can host it home, for free?). As a result of this, I stumbled upon a «problem» that annoyed me a bit; loopback-support — the ability to reach your services using your external IP, and hence applying port-forwards (this way you could use «ssh externalip -p port number>» regardless if you are home or not). This is quite useful if you move between different networks a lot (e.g. using a laptop — which was the case for me). This feature is known as tromboning, or hairpinning, and is something that often works on cheap routers you get from your ISP. So, why shouldn’t this work on a Cisco-device?

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Sep 21 / jocke

Linux: Search inside files

You ever wanted to find something within loads of files? And you’d like the matching lines to be printed? And with line-numbers? What if you’d like the X lines above/below matching lines to be printed? No problem.

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Sep 17 / jocke

Installing Cisco Unified Communications Manager 8 on ESXi

Having problems getting CUCM 8 installed on a VM running on ESXi? So did I.

Critical Error
Validation error on HSSI mode:
VMWare Validation Failure:
Unable to validate VMWare based server disk settings.
Please check SCSI disks are at least 72GB in size and are located at 0:0 (and 0:1 in a two disk config) in machine settings.

I ran into an issue when installing CUCM 8.0.2 on a VM running on ESXi 4.1. The installer complained that it needed at least 72GB of hard-drive space. As I hadn’t read the hardware-requirements for the CUCM, I spent much of my time testing out different HDD-settings on the VM. At first I thought that it didn’t like the ESXi’s thin-provisioning, but after a while, I found out that the issue was with other settings on the VM — specifically how many CPU’s and how much RAM it needs. It’s also recommended that you choose the OS that is as close to CUCM as possible.

So, without further ado, here’s the settings you’ll need;

  • CPUs: >=2
  • Memory: >=2GB
  • Hard disk: >=73GB (you can turn on Thin-provisioning if you want)
  • Guest Operating System: Linux -> Red Hat Enterprise Linux 4 (32-bit)

Keep in mind that this is minimum, and that you can’t set them lower after the install is done, as CUCM does the same check every time it boots.