Eric Stewart: Running Off At The Mouth

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CCIE Studies: OSPF E1 vs E2 For Dummies

by on Mar.14, 2015, under Networking, Technology

Restating what I’ve pulled from other sources, and clarifying that there actually is a difference. It’s commonly said that “E2 routes will not include path cost,” but that’s an oversimplification of the difference and a somewhat misleading statement, because, in some cases, path cost is considered. Here’s the scoop.

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Nexus 7700 Part III: Breakout Interfaces

by on Jul.15, 2014, under Networking, Technology

It is possible on the Nexus 7700 line, with certain optics, to break out 40Gb (and eventually 100Gb) to 4x10Gb interfaces (no one knows for sure what 100Gb will do – it will either be 8x10Gb or 10x10Gb). In this post I go over how $JOB is doing it (at least with the 40Gb) and what you need to be aware of. I do touch a little bit on the 100Gb breakout future and explain why we were looking to do it.

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Nagios’s check_ntp_peer, IPv6, and ntp.conf

by on Jun.03, 2014, under Networking, Technology

As is not unusual, I run into an edge case that might be specific to us. While attempting to monitor IPv6 reachability of an NTP server I had just upgraded, I ran into an interesting case where NTP was responding via IPv4, but not IPv6, and they appeared to be identically configured.

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Perl’s Net::SNMP and get_table() – Bulk vs Next Request

by on Sep.27, 2013, under Networking, Technology

An attempt to communicate an issue (and the solution) I ran into with Perl’s Net::SNMP function “get_table”, that would result in a “The message size exceeded the buffer maxMsgSize of 1452” error. It took a couple of packet captures and Googling to figure out why this problem was occurring and implement a fix.

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Creating your own CentOS 6.2 LiveDVD

by on Jun.12, 2012, under Computers, Technology

When I started, I had no real knowledge of kickstart files. Now I know a little, and I figured I could share with other CentOS/Red Hat admins how one might customize a kickstart file to create a LiveDVD ISO.

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Synergy secured with Cygwin SSHD on Windows 7

by on May.02, 2012, under Computers, Networking, Technology

Subject to changes: Windows 7 is where I find myself spending most of my time: At home it’s my game machine, and at work … well, it makes a passable platform for my email and web browsers. So, that’s where my keyboard and mouse live. However, at both home and work I have an Ubuntu (Linux variant) system next to the Windows box, and occasionally I add my laptop (also running Ubuntu) to the mix. I use Synergy to control the Linux systems from the Windows system, and use SSH tunnels to secure the connection. Here’s how I do it.

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Increasing a CentOS Linux LVM partition size, the dangerous way

by on Feb.23, 2012, under Computers, Technology

There are two ways to do this – the easy, safe way, and the somewhat cleaner but more dangerous way. I’ll be providing the steps for doing it the not quite so easy, somewhat more dangerous way, as it makes your partitions look nicer. This is probably the most unsafe way to do it, and there’s probably easier ways to accomplish what I’m trying to do, but here’s what appears to have worked.

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CentOS, cisco monitor ports, and IPv6

by on Jan.15, 2012, under Networking, Technology

I finally got the job I’ve been wanting for, oh, nearly a decade now (if not more). In this job I’m the go-to admin for the servers (almost all CentOS based) that support a large (3000+ device) network. Cisco routers run the network, and we have servers that are connected to “monitor” ports. One of the principle tasks of these servers are to allow network engineers to run packet captures. Thing is, interesting things can happen as far as IPv6 is concerned when you have systems getting IPv6 router advertisements on server interfaces that don’t actually do more than just accept packets …

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Backup Exec and DFS Files

by on Dec.25, 2010, under Computers, Technology

I now am the master of backups at my new place of employment. I’ve been learning a bit about Backup Exec, and ran into an interesting issue. In the hopes of preventing others from taking the three or four days it took me to track the issue down, I relate the experience here.

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Google Voice has gone public

by on Jun.23, 2010, under Cell Phones & Providers, Networking, Technology

A quickie blog post about Google Voice, a service where Google provides you the ability to read your voice mail or ring multiple numbers from one phone number.

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