Category Archives: Memorandum

Posts with the category “Memo” contain no new stuff for the Internet community but provide some useful aggregations of information for certain IT related things.

Measuring Temperatures with PCsensor’s TEMPerHUM Sensor

DIY/Bastelarbeiten, Monitoring, MRTG/Routers2, Raspberry Pi, Template, Tutorial/Howto, , , , , , , ,

I am always interested in capturing real values via hardware devices in order to generate the appropriate graphs with my monitoring system. Of course, the outside temperature in our city was at the pole position for such a project. Therefore I ordered a few temperature/humidity sensors from PCsensor (via eBay), plugged them via USB on my Raspberry Pi (Raspbian Linux), and queried them via SNMP from my MRTG/Routers2 monitoring server. Here is the whole story:

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Palo Alto Firewall: Installation from Scratch till Panorama

Memorandum, Palo Alto Networks, , , ,

This is my basic checklist when installing a new Palo Alto firewall. I used it for a few clusters during the last weeks. It shows the steps required for a PA firewall from the unpacking until it is plugged into Panorama, the central management platform from Palo Alto.

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MRTG/Routers2: Statistiken für AVM’s FRITZ!Box

FRITZ!Box, MRTG/Routers2, Network, Template, , , , ,

Natürlich wollte ich auch Statistiken von der FRITZ!Box in meiner MRTG/Routers2-basierten Monitoring Umgebung haben. Glücklicherweise habe ich ein Tool namens upnp2mrtg gefunden, welches exakt das macht, nämlich die Interface-Statistik des WAN Ports der FRITZ!Box über UPnP abzufragen und für MRTG aufzubereiten. Sehr einfach zu benutzen. Hier also eine Anleitung mit einigen zusätzlichen Hinweisen.

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IPsec Site-to-Site VPN Cisco ASA <-> AVM FRITZ!Box

Cisco ASA, FRITZ!Box, IPsec/VPN, Template, , ,

Mit diesem Beitrag möchte ich zeigen, wie man ein Site-to-Site VPN von der FRITZ!Box zu einer Cisco ASA Firewall aufbaut. Mein Laboraufbau entspricht dabei dem typischen Fall, bei dem die FRITZ!Box hinter einer dynamischen IP hängt (klassisch: DSL-Anschluss), während die ASA eine statische IP geNATet bekommt.

Beide Geräte habe ein policy-based VPN implementiert, so dass das hier endlich mal ein Fall ist, wo man nicht durch den Mix einer route-based VPN-Firewall und einer policy-based VPN-Firewall durcheinander kommt. Man muss bei beiden Geräten einfach das eigene sowie das remote Netzwerk eintragen, ohne weitere Routen zu ändern.

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At a Glance: HTTP Proxy Packets vs. Normal HTTP Packets

At a Glance, Network, , , , , ,

I am currently in touch with a few HTTP proxy installations. As every time when troubleshooting network issues, I am looking at Wireshark on the network and trying to understand the different packets.

Here is a short overview of the differences between HTTP requests that are sent directly to the destination and HTTP requests that are sent via a proxy. Wireshark screenshots and a downloadable pcap round things up.

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FTP Proxy Authentication Format “Check Point”

Authentication, Network, Template, , , , ,

Short memo: This is the FTP proxy authentication format of “Check Point” for the FileZilla FTP Client. I needed it for my Cisco WSA (Web Security Appliance) laboratory in the case of an enabled proxy authentication.

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MRTG/Routers2: Adding a Linux Host

Linux, MRTG/Routers2, Network, Tutorial/Howto, , , , ,

This post describes how to add a Linux machine to the MRTG/Routers2 monitoring server. First, the host must be able to process SNMP requests. Then, a *.cfg file for MRTG/Routers2 is created by running the “cfgmaker” tool with a host-template. Since a few values are wrong in the cfgmaker file, I also explain how to correct them. Finally, I am adding the mrtg-ping-probe lines to the configuration.

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MRTG/Routers2: Counting Traceroute Hops

MRTG/Routers2, Network, Template, Tutorial/Howto, , , ,

I was interested in generating graphs within the MRTG/Routers2 monitoring system that display the number of hops for an IP connection through the Internet. In my opinion its interesting to see the different routing run times/hop counts e.g. for remote offices that are connected via dynamic ISP connections such as DSL. Therefore, I wrote a small script that executes a traceroute command which can be called from MRTG.

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MRTG/Routers2: Measuring Ping Times

MRTG/Routers2, Ping/Traceroute, Template, , , ,

MRTG can also evaluate values from external scripts such as the “mrtg-ping-probe” program which returns the round-trip time from the initiated ping command to the specified destination host. With an additional GraphStyle called “range” from Routers2, these ping times can be displayed in the monitoring system. This graph style shows the “min” and “max” RTT in one vertical line instead of two independent lines.

Since there is not much to say about this process, I will only paste my MRTG/Routers2 config for mrtg-ping-probe and will show a few example graphs here.

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MRTG/Routers2: Adding a Switch

MRTG/Routers2, Network, Tutorial/Howto, , , ,

The Multi Router Traffic Grapher (MRTG) can, of course, not only monitor routers via SNMP, but any devices that support the Simple Network Management Protocol, e.g., switches. With the tool “cfgmaker” it is quite easy to add switches with many ports to the monitoring system. However, some subsequent work is needed to have a clean configuration. This blog post presents a step-by-step guide for adding a switch into MRTG/Routers2.

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MRTG/Routers2: Adding a Cisco Router

Cisco Systems, MRTG/Routers2, Network, Tutorial/Howto, , , ,

This post shortly explains the process of adding a Cisco router into the monitoring system “MRTG with Routers2” as I explained it here. It gives an example on how SNMP is activated on the router and how the *.cfg file for MRTG/Routers2 is created with the additional values for CPU and memory usage.

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MRTG with RRDtool and Routers2 – Installation from Scratch

Linux, MRTG/Routers2, Network, Tutorial/Howto, , , , , , ,

I always wanted to monitor my private network with an open source tool. Since I knew some nice statistics, e.g. from the DE-CIX (printed with RRDtool) or from the Uni-Gießen (generated with MRTG), I had the idea of installing such a system by myself. Luckily I found a book from Steve Shipway, called “Using MRTG with RRDtool and Routers2“, which actually disappointed me because it did not offer a complete installation guide but mainly further information about fine-tuning the appropriate tools.

Therefore, I want to show a complete step-by-step installation of all the needed tools in order to monitor a network with MRTG, RRDtool and Routers2.  “From scratch” means that there are no prerequisite to this installation guide except a plain Linux server (in my case a Ubuntu Linux) such as presented here. Okay, let’s go: Continue reading MRTG with RRDtool and Routers2 – Installation from Scratch →

At a Glance: False Positive

At a Glance,

I am always struggling with the definition of a “false positive” though it should be easy. Since I love figures that point out the most important facts I drew one concerning the false positive etc. structure. It is based on the example of a malware detection in which an engine decides whether a piece of software is a malware or not. Here it is:

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IPsec Site-to-Site VPN Palo Alto <-> AVM FRITZ!Box

FRITZ!Box, IPsec/VPN, Palo Alto Networks, Template, , ,

Wer im Büro auf eine Palo Alto Networks Firewall setzt und von zu Hause hinter seiner FRITZ!Box per VPN im Büro arbeiten möchte, der muss die richtigen Einstellungen auf beiden Geräten finden. Genau das habe ich getan und stelle hier die entsprechenden Details online. Viel Spaß dabei. ;)

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IPsec Site-to-Site VPN Juniper ScreenOS <-> AVM FRITZ!Box

FRITZ!Box, IPsec/VPN, Juniper Networks, Template, , , ,

Hier kommen die Einstellungen die nötig sind, um ein Site-to-Site VPN zwischen einer AVM FRITZ!Box und einer Juniper ScreenOS Firewall herzustellen. Neben einigen Anleitungen im Netz habe ich selber ein paar Einstellungen getestet, um eine möglichst detaillierte *.cfg Datei zu haben. Außerdem ist erfreulicherweise anzumerken, dass die Juniper auch ein statisches VPN zu einer dynamischen Adresse erlaubt und somit sogar beide Seite einen Verbindungsaufbau initiieren können. Mit dem VPN Monitor von Juniper wird der Tunnel konstant “up” gehalten.

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