Author Archives: Christian Reusch

IPv4 Basics – Part 1: DHCP (Dynamic Host Configuration Protocol)

DHCP - Address Renewal

IPv4 – Basics – Part 1: DHCP (Dynamic Host Configuration Protocol) Today I will start a small series, which will cover some basic behaviour of the IPv4 protocol suite and is meant for reimagine and a little bit baselining. I will start the series with the Dynamic Host Confirguration Protocol (DHCP). History: In the Classless Inter Domain Routing (CIDR) environment

Rate this:

Read more

The relationship between the Maximum Transmission Unit (MTU) and the Maximum Segment Size (MSS)

PDUs of the TCP(IP protocol suite (stack)

A few days ago I have read an answer about the Maximum Segment Size (MSS) at the Wireshark Q&A site.

The answer had shacked me up a little bit, because the author wrote that the MSS is not negotiated. First I had thought that I missed something big in my understanding of the Maximum Segment Size (MSS). But after a dive into the world of the RFCs I realized that I have just misinterpreted /mistranslated the authors statement.

Rate this:

Read more

End User Experience measuring to support the network analysis process

Offline analysis with the HarViewer

The number of Graphical User Interfaces (GUI) which are using HTTP as the application protocol is still growing up. And each single website of these applications has often a complex dynamical content. So the “End User Experience View” is getting more and more important, because for the above mentioned reasons it is not easy to realize if the whole content has been loaded with nothing more then a trace file and no deeper knowledge of the application.

Rate this:

Read more

Packet discards at VMXNET3 adapter on ESXi host

netstat -e

Strange Packet discards In the last time I encountered to a strange problem. The following components have been involved: Win2008 R2 servers with VMXNET3 Adapters. Used VMware configuration vCenter Server 5.1.0a ESXi 5.1 Patch 1 Looking at “netstat -e” shows the following strange output. The discard counters for for send and receive side were growing and had also the same

Rate this:

Read more

Cyberattack at “Deutscher Bundestag” and my personal experience with an cyber attack

Cyber Attack at “Deutscher Bundestag”
While I have been writing my new article about WLAN basics I read an article about the hacker attack at the “Deutscher Bundestag”.
The interesting thing about this attack is, that it seems to be a full hit.
Obviously they are totally compromised, because they lost the last bastion the admin rights of their network. So this is one of the most fatal error you can have. This article inspired me to a personal memory about the history of it security.

Rate this:

Read more