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Sunday, August 20, 2017

Net-SNMP on Windows with SSL

Recently, I found my older Windows version (5.2.2) of the Net-SNMP tools didn't have support for AES privacy protocol for SNMPv3 when I tried to use it. I grabbed the latest pre-compiled Windows binaries ( from the site and found they didn't have AES support either. After some reading, I found I needed OpenSSL DLLs and old ones at that - version 0.98. This wasn't going to work; I was going to need to compile this myself.

I tried with MinGW included with Strawberry Perl, but 'gmake.exe' kept giving errors. Now I needed Microsoft Visual Studio Community and some help.

Monday, June 26, 2017

Run MAD - one month to go ...

According to the following tweet, on or about 20 July, 2016, I began my run-a-mile-everyday thing with the hashtag #RunMAD - as in - Run Mile-a-Day.

The goal was simple, run at least 1 mile every day for at least 1 year. Some rules:

  1. Run at least 1 contiguous non-stop mile every day
  2. A day is between 12:00:00a and 11:59:59p
  3. No "saving" miles (i.e., 2 miles today doesn't mean 0 miles tomorrow)
  4. Do this for at least 1 year from the start date

Unfortunately, I don't quite remember the official "start date" - if I tweeted the day I started or if I made sure I'd stuck with it for at least 1 week or so before posting so boldly. In any case, after 11 or so months with 1 or so left to go, I'm planning on extending to at least Labor Day, 2017 to make sure I've completed a full year. I've done this everyday so far, whats a few more ... ?

Friday, May 12, 2017

Digital Disruption in Service Providers

Every industry can be digitally disrupted - even those that claim to provide the very digital transformation enterprises so desperately seek.

The true benefit of software-defined networking is not separation of control plane and data plane - that doesn't work at scale. It's not easier centralized control and the end of command line with more fancy acronyms like YANG, XML-RPC and REST APIs. The "revolutionary" idea is the separation of the network layer into physical connectivity and logical connectivity. I quote "revolutionary" as tongue-in-cheek - the OSI model always had a separate physical layer and network layer, but in the long move from circuits to fully-managed, bundled MPLS, we seem to have forgotten that.

Wednesday, May 10, 2017


A seemingly normal DNS packet:

ETH: dst:98:76:54:32:10:ab  src:ab:cd:ef:12:34:56  type:0x0800
IPv4: version:4  hlen:5  tos:0x00  length:190  id:44821
IPv4: flags:0x00  offset:0  ttl:128  protocol:0x11  checksum:0xb060
IPv4: src:  dst:
UDP: src:53  dst:13245  length:170  checksum:0x8756
DNS: id:21817  qr:1  opcode:0  flags:0x18  rcode:0
DNS: qdCount:1  anCount:4
DNS: nsCount:0  arCount:0
DNS::Question: name:www.www.com
DNS::Question: type:1  class:1
DNS::RR: name:www.www.com
DNS::RR: type:5  class:1  ttl:64  rdlength:16
DNS::RR::CNAME: cname:www.Johnny.com
DNS::RR: name:www.www.com
DNS::RR: type:5  class:1  ttl:64  rdlength:17
DNS::RR::CNAME: cname:www.Fingers.com
DNS::RR: name:www.www.com
DNS::RR: type:1  class:1  ttl:64  rdlength:4
DNS::RR::A: address:
DNS::RR: name:www.www.com
DNS::RR: type:1  class:1  ttl:64  rdlength:4
DNS::RR::A: address:

But upon some decoding ...

Thursday, May 04, 2017

Net::SSH2 Upgrade Access to Cisco

I upgraded my Strawberry Perl to 5.24 and my GNS3 test lab for SSH access via CRAPPS suddenly didn't work.

Knowing the Perl version changed, I checked and the Net::SSH2 version changed (0.58 to 0.63). Troubleshooting was pretty easy - just a quick Perl script to open a connection and die on failure with error:

use strict;
use warnings;
use Net::SSH2;

my $ssh2 = Net::SSH2->new();
$ssh2->connect('') or $ssh2->die_with_error;
print "Success\n";

The error was: Unable to exchange encryption keys (-8 LIBSSH2_ERROR_KEY_EXCHANGE_FAILURE). OK, so I said troubleshooting was easy ... the solution ... maybe not so much?

Tuesday, September 13, 2016

Technology Themes

In my career of technology consulting, projects over the years have been driven by some high level themes regardless of:

  • the technology (i.e., network design, management, security, etc.),
  • the domain (i.e., local, wide-area, data center, etc.),
  • or the customer (i.e., retail, healthcare, banking, etc.)

To summarize roughly by decade:

Decade Theme
1980s Technology Evangelism
1990s Technology Deployment
2000s Technology Evaluation
2010s Technology Justification

I haven't been in information technology for that long,


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