Author: René Jorissen

René Jorissen works as Solution Architect for QMonkeys in the Netherlands. Network Infrastructures are the primary focus. René works with equipment of multiple vendors, like HPE Networks, FortiNet, SentinelOne, Phished, Holm Security, Microsoft services and many more. René is Aruba Certified Edge Expert (ACEX #26), Aruba Certified Mobility Expert (ACMX #438), Aruba Certified ClearPass Expert (ACCX #725), Aruba Certified Design Expert (ACDX #760), CCNP R&S, FCNSP and Certified Ethical Hacker (CEF) certified. You can follow René on Twitter and LinkedIn.

Other stuff...

Company transportation….

René Jorissen on October 23, 2008 • 1 Comment

Today I am working at a customer who has two locations in a very very small town. The “head quarters” is located in the center of town and the factory is located outside the town. On both locations I have to replace all network components, so there is some traveling between both locations. So one … Read More

Switching

IEEE 802.3x FlowControl between Cat3750E and Cat2960

René Jorissen on October 23, 2008 • 1 Comment • Tags: #2960 #3750 #3750e #8023x #catalyst #cisco #congested #control #flow #flowcontrol

I have a network with two Catalyst 3750E switch stacks, which are connected with a 2 x 10Gbps Etherchannel. Every stack facilitates a ring topology of approximately 10 to 15 Catalyst 2960 switches. Two of the 2960 are connected with 1Gbps links to a switch stack to create the ring topology. So lets say that … Read More

Configuration Example

Telnet Time-Out is killing me….

René Jorissen on October 22, 2008 • 0 Comments • Tags: #connection #ip #out #synwait #synwait-time #tcp #telnet #time #timed

Aaarrrgggghhh, I hate it when I would like to telnet into a device and enter the wrong IP address. This means, by default, waiting for 30 seconds before being able to correct the IP address and start a new telnet session, because there is no escape sequence. SW01#telnet 10.100.12.250 Trying 10.100.12.250 … % Connection timed out; … Read More

Switching

What is an UPLINK port?

René Jorissen on October 21, 2008 • 0 Comments • Tags: #0x9000 #keepalives #trunk #uplink

A colleague recently encountered some problems with keepalives on switch ports. He wrote a post about it. Keepalives are, quoted from his blog post: By default Cisco routers and switches periodically test their (Fast) Ethernet links by sending out Loopback frames (ethertype 0×9000) addressed to themselves. Call it a “L2 self-ping” if you will. In … Read More

Configuration Example

Alias IOS Command

René Jorissen on October 20, 2008 • 0 Comments • Tags: #alias #configure #exec #interface

When configuring a router I often use different show commands to check or troubleshoot the configuration. I always hate to type in the whole show command, so I use aliases instead. Aliases are also used in the Open Source community, when working with a terminal. There are multiple options for the alias command, lets take … Read More