With this blog page I would like to share my little configuration snippets with all interested people. Because in some moments I was faced with the question, what was that again? Which command brought you the fastest result or what did I have to consider in order to comply with the requirements of the information security experts.

Most often I was on the console of Cisco switches, routers and the ASA. Therefore, most of the snippets are tagged Cisco. The one or two snippets for the Palo Alto networks firewall did sneak in, though.

The snippets are mostly kept very compact. I'm sure there is a better way to reach the objective. It helped me a lot at the time and can certainly be used at least as an idea.

Palo Alto PA-200 Attacks

overview of file blocking profiles

The firewall uses file blocking profiles to block specified file types over specified applications and in the specified session flow direction (inbound/outbound/both).

Palo Alto PA-200 Attacks

Protection against ransomware (filtering of Windows PE files)

To protect against ransomware, Windows PE executables should be filtered by content and not just by extension.

Palo Alto PA-200 Factory reset

How to perform a factory reset on a PA-200?

The following steps describe how to perform a factory reset on a PA-200.


Tuning the Tunnel Default Gateway

How do I implement the requirement that IPSec VPN clients can also surf the Internet but are routed through a dedicated Internet firewall?

Cisco ASA licences

Which ASAv licences are active?

The following command show license feature can be used to quickly check which ASAv licences are activated. The result should look something like this.


Allow ICMP through a VPN tunnel

Why can't I send a PING through a remote access IPSec tunnel that terminates on an ASA?

Cisco ASA Cluster Update

Firmware ASDM Update for an Active/Standby Cluster

This article describes how a software update of the firmware and the ASDM can be carried out on an active Cisco ASA firewall cluster. With this method, no interruption of the actual operation of the firewall is required.

Palo Alto PA-200

Adjusting the fan noise for PA-200

I have the small PA-200 under my desk and the fan is always on with the factory settings.

Cisco ASA Cluster

Configuration recovery of the standby cluster unit

In four simple steps, the configuration of the standby cluster unit can be restored via the primary unit. The following article shows what these steps are.

Cisco ASA Cluster

Create Active/Standby Firewall Cluster

The method described here only includes the absolutely necessary basic configuration of the firewall cluster. All further configurations of policies and firewall rules are then only carried out via the active cluster unit. For the initialisation of a firewall cluster in active/standby mode, the required steps can be grouped into the following chapters.

Cisco ASA Attacks

Set up protection against TCP SYNC attacks

The TCP SYNC attack, also known as a "half-open attack", is an attack against TCP network connections. The attacker abuses the three-way handshake of TCP. In this type of attack, many half-open TCP connections are created on the server. This ties up resources on the server that are no longer available for actual use.

Cisco ASA Attacks

Protection against IP spoofing attacks

IP spoofing is used especially when a response packet is not necessary. The attack is most effective when there is a trust relationship between the systems in a network.


Quickly erase VPN tunnel group and group policy

Erasing a VPN configuration that is no longer required can be done easily, quickly and effectively via the command line interface (CLI) with only two commands.

Cisco ASA

Firewall sends a reset instead of a drop

If a firewall rule does not allow the connection to be established by a DENY, the ASA normally sends a silent drop packet. This behaviour is not always suitable from a usability point of view for the clients in the LAN and their applications.


Enable blocking of a number of authentication attempts

​By default, no limit on the maximum number of failed attempts allowed for authentication of local users is active. This means that an attacker can brute-force a local user and his password as long as he wants. To prevent this, the number of password retries for a locally managed user has to be limited.

In accordance with the legal requirements of data protection law (in particular the BDSG as amended and the European Data Protection Regulation 'DS-GVO'), we inform you below about the nature, scope and purpose of the processing of personal data by our company. This privacy policy also applies to our websites and social media profiles. With regard to the definition of terms such as "personal data" or "processing", we refer to Art. 4 DS-GVO.

Name and contact details of the person(s) responsible

Our responsible person(s) (hereinafter "responsible person") within the meaning of Art. 4 fig. 7 DS-GVO is:
Jens Mahnke
Karl-Kunger-Str. 56
12435 Berlin Germany
Email address:

Types of data, purposes of processing and categories of data subjects

Below we inform you about the type, scope and purpose of the collection, processing and use of personal data. 

1. types of data we process
Usage data (access times, websites visited, etc.), communication data (IP address, etc.),

2. purposes of the processing according to Art. 13 para. 1 c) DS-GVO 
Technical and economic optimisation of the website, optimisation and statistical evaluation of our services, improving user experience, compilation of statistics,

3. categories of data subjects according to Art. 13 (1) (e) DS-GVO
Visitors/users of the website,

The data subjects are collectively referred to as "users".

Legal basis for the processing of personal data

Below we inform you about the legal basis for the processing of personal data. 1. if we have obtained your consent for the processing of personal data, Art. 6 para. 1 sentence 1 lit. a) DS-GVO is the legal basis. 2. if processing is necessary to comply with a contract or to carry out pre-contractual measures in response to your request, Art. 6 (1) sentence 1 lit. b) DS-GVO is the legal basis. If the processing is necessary to comply with a legal obligation to which we are subject (e.g. statutory retention obligations), Art. 6 (1) sentence 1 lit. c) DS-GVO is the legal basis. If the processing is necessary to protect the vital interests of the data subject or another natural person, the legal basis is Art. 6 (1) sentence 1 lit. d) DS-GVO. If the processing is necessary to protect our legitimate interests or the legitimate interests of a third party and your interests or fundamental rights and freedoms are not overridden in this respect, Art. 6 para. 1 sentence 1 lit. f) DS-GVO is the legal basis.

Disclosure of personal data to third parties and order processors

As a matter of principle, we do not pass on any data to third parties without your consent. However, if this should be the case, then the data will be passed on on the basis of the aforementioned legal grounds, e.g. when data is passed on to online payment providers for the fulfilment of a contract or due to a court order or because of a legal obligation to hand over the data for the purpose of criminal prosecution, to avert danger or to enforce intellectual property rights. We also use processors (external service providers e.g. for web hosting of our websites and databases) to process your data. If data is passed on to the processors as part of a contract processing agreement, this is always done in accordance with Art. 28 DS-GVO. In doing so, we select our processors carefully, monitor them regularly and have been granted a right to issue instructions regarding the data. In addition, the processors have to have taken suitable technical and organisational measures and comply with the data protection regulations according to the BDSG n.F. and the DS-GVO.

Data transfer to third countries

The adoption of the European General Data Protection Regulation (GDPR) has created a uniform basis for data protection in Europe. Your data is therefore predominantly processed by companies to which the GDPR applies. However, if processing is carried out by services of third parties outside the European Union or the European Economic Area, these have to fulfil the special requirements of Art. 44 ff. DS-GVO must be complied with. This means that the processing takes place on the basis of special guarantees, such as the officially recognised determination by the EU Commission of a level of data protection corresponding to the EU or the observance of officially recognised special contractual obligations, the so-called "standard contractual clauses". Insofar as we obtain your express consent to the transfer of data to the USA due to the invalidity of the so-called "Privacy Shield" in accordance with Article 49 (1) sentence 1 lit. a) DSGVO, we point out in this regard the risk of secret access by US authorities and the use of the data for monitoring purposes, possibly without any legal remedy for EU citizens.

Deletion of data and storage period

Unless expressly stated in this data protection declaration, your personal data will be erased or blocked as soon as you revoke the consent given for processing or the purpose for storing the data no longer applies or the data are no longer required for the purpose, unless their continued storage is necessary for evidence purposes or is contrary to statutory retention obligations. This includes, for example, retention obligations under commercial law for business letters in accordance with § 257 para. 1 of the German Commercial Code (HGB) (6 years) and retention obligations under tax law for receipts in accordance with § 147 para. 1 of the German Fiscal Code (AO) (10 years). When the prescribed retention period expires, your data will be blocked or deleted unless the storage is still necessary for the conclusion or fulfilment of a contract.

Existence of automated decision making

We do not use automated decision making or profiling.

Provision of our website and creation of log files

1. If you use our website for information purposes only (i.e. no registration and no other transmission of information), we only collect the personal data that your browser transmits to our server. If you wish to view our website, we collect the following data:

  • IP address;
  • Internet service provider of the user; 
  • Date and current time of the request;
  • browser type;
  • language and browser version;
  • Content of the retrieval;
  • Time zone;
  • Access status/HTTP status code;
  • Amount of data;
  • Websites from which the request came;
  • Operating system.

This data is not stored together with other personal data about you.

2. This data serves the purpose of user-friendly, functional and secure delivery of our website to you with functions and content as well as its optimisation and statistical evaluation.

3. The legal basis for this is our legitimate interest in data processing in accordance with Art. 6 (1) sentence 1 lit. f) DS-GVO, which also lies in the above purposes.

4. For security reasons, we store this data in server log files for a storage period of 70 days. After this period, they are automatically erased, unless we need to keep them for evidence purposes in the event of attacks on the server infrastructure or other legal violations.

Contacting us via contact form / email / fax / post

1. When contacting us via contact form, fax, mail or email form, your data will be processed for the purpose of handling the contact request.

2. If you have given your consent, the legal basis for processing your data is Art. 6 (1) sentence 1 lit. a) DS-GVO. The legal basis for the processing of data transmitted in the course of a contact request or email form, letter or fax is Art. 6 para. 1 p. 1 lit. f) DS-GVO. The responsible party has a legitimate interest in processing and storing the data in order to be able to answer users' enquiries, to preserve evidence for liability reasons and, if necessary, to be able to comply with its statutory retention obligations for business letters. If the objective of the contact is the conclusion of a contract, the additional legal basis for the processing is Article 6 (1) sentence 1 lit. b) DS-GVO.

3. We may store your details and contact request in our Customer Relationship Management System ("CRM System") or similar system.

4. The data is erased as soon as it is no longer required to achieve the purpose for which it was collected. For the personal data from the input mask of the contact form and those sent by email form, this is the case when the respective conversation with you has ended. The conversation is ended when it is clear from the circumstances that the matter in question has been conclusively clarified. We store enquiries from users who have an account or contract with us until two years after termination of the contract. In the case of legal archiving obligations, deletion takes place after their expiry: end of commercial law (6 years) and tax law (10 years) retention obligation.

5. You have the option to revoke your consent to the processing of personal data at any time in accordance with Art. 6 para. 1 p. 1 lit. a) DS-GVO. If you contact us by email form, you can object to the storage of personal data at any time.

Rights of the person concerned

1. Objection or revocation against the processing of your data

Insofar as the processing is based on your consent pursuant to Art. 6 para. 1 sentence 1 lit. a), Art. 7 DS-GVO, you have the right to revoke your consent at any time. This does not affect the lawfulness of the processing carried out on the basis of the consent until the revocation.

Insofar as we base the processing of your personal data on the balance of interests pursuant to Art. 6 (1) p. 1 lit. f) DS-GVO, you may object to the processing. This is the case if the processing is not necessary, in particular, for the compliance with a contract with you, which is shown by us in each case in the following description of the functions. When exercising such an objection, we ask you to explain the reasons why we should not process your personal data as we have done. In the event of your justified objection, we will review the merits of the case and either cease or adapt the data processing or show you our compelling legitimate grounds on the basis of which we will continue the processing.

You can object to the processing of your personal data for the purposes of advertising and data analysis at any time. You can exercise the right to object free of charge. You can inform us of your advertising objection using the following contact details: Jens Mahnke
Karl-Kunger-Str. 56 12435 Berlin Germany
Email address:

2. Right to information You have a right to information about your personal data stored by us in accordance with Art. 15 DS-GVO. This includes, in particular, information about the processing purposes, the category of personal data, the categories of recipients to whom your data has been or will be disclosed, the planned storage period, the origin of your data if it has not been collected directly from you.

3. Right to rectification You have the right to have inaccurate data corrected or correct data completed in accordance with Art. 16 DS-GVO.

4. Right to deletion You have the right to have your data stored by us deleted in accordance with Art. 17 DS-GVO, unless legal or contractual retention periods or other legal obligations or rights to further storage prevent this.

5. Right to restriction

You have the right to request a restriction in the processing of your personal data if one of the conditions in Art. 18 (1) a) to d) DS-GVO is complied with:

  • If you contest the accuracy of the personal data concerning you for a period of time which enables the controller to verify the accuracy of the personal data;
  • the processing is unlawful and you object to the erasure of the personal data and request instead the restriction of the use of the personal data;
  • the controller no longer needs the personal data for the purposes of the processing but you need them for the establishment, exercise or defence of legal claims; or
  • if you have lodged an objection to the processing pursuant to Art. 21 (1) DS-GVO and it is not yet clear whether the legitimate reasons of the controller outweigh your reasons.

6. Right to data portability You have a right to data portability in accordance with Art. 20 DS-GVO, which means that you can receive the personal data we hold about you in a structured, common and machine-readable format or request that it be transferred to another controller.

7. Right to complain You have the right to complain to a supervisory authority. As a rule, you can contact the supervisory authority for this purpose, in particular in the Member State of your place of residence, your workplace or the place of the alleged infringement.

Data security

In order to protect all personal data transmitted to us and to ensure that data protection regulations are complied with by us as well as by our external service providers, we have taken appropriate technical and organisational security measures. Therefore, among other things, all data is transmitted between your browser and our server via a secure SSL connection.

Status: 09/09/2022

Jens Mahnke
Karl-Kunger-Strasse 56
12435 Berlin
Email form:

Disclaimer - legal information 

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The free and freely accessible contents of this website have been created with the greatest possible care. However, the provider of this website accepts no responsibility for the correctness and up-to-dateness of the free and freely accessible journalistic advice and news provided. Contributions identified by name reflect the opinion of the respective author and not always the opinion of the provider. The mere fact of calling up the free and freely accessible content does not create any contractual relationship between the user and the provider; in this respect, the provider's intention to be legally bound is lacking. 

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This website contains links to third-party websites ("external links"). These websites are subject to the liability of the respective operators. When the external links were first created, the provider checked the external content for any legal violations. At that time, no legal violations were apparent. The provider has no influence on the current and future design and content of the linked pages. The inclusion of external links does not imply that the provider adopts the content behind the reference or link as its own. It is not reasonable for the provider to constantly monitor the external links without concrete indications of legal violations. However, such external links will be erased immediately if legal violations become known. 

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