Ireland: Are Dynamic IP Addresses Personal Data?

Last Updated: 3 October 2016
Article by Philip Nolan, Oisin Tobin and Jevan Neilan

Whether IP addresses, a type of online identifier, are classified as personal data has been the subject of considerable debate. In May 2016, an independent advisor to the EU's highest court issued an Opinion, finding that IP addresses are deemed to be personal data in instances where they are handled by a website operator.

The case, Patrick Breyer v. Bundesrepublik Deutschland,Case C-582/14, concerned a challenge brought by Mr Breyer against the German State. He sought to challenge the collection, use and storage of IP access logs across State-owned websites. One of the core questions was whether IP addresses, coupled with the access time, are personal data. The court's independent advisor, the Advocate General, took the view that, in certain circumstances, dynamic IP addresses can constitute personal data. We examine this case and what it may mean.

What are IP addresses?

IP addresses are one of the digital fingerprints left by a device accessing the internet. Website operator's use and store IP addresses for various purposes, including to serve content and improve security. These strings of numbers identify laptops, smartphones and other devices to both the internet service provider ("ISP") and website operators. Usually, however, only one IP address will be assigned per subscriber or per household. In other words, multiple devices in one household could be identified by the same IP address.

'Dynamic' IP addresses, as the name suggests, are 'dynamic' rather than 'static', meaning that the subscriber or household is frequently assigned a 'new' address. As a result, the subscriber or household is not generally identified by a single, unique IP address. Generally speaking, dynamic IP addresses are not, on their own, sufficient to identify an individual. However, when combined with a date and time of access, the ISP can identify the subscriber.

The question for the court

Mr Breyer brought this challenge against the German State, alleging that it was processing his personal data, in this case his IP address logs, without a legal basis. The German Federal Court referred questions to the Court of Justice of the European Union ("CJEU") for determination. In particular, the German court asked the CJEU whether a dynamic IP address, held by a website operator, could constitute personal data if an ISP holds additional information that would identify the individual. Under EU law, personal data is information that identifies or has the ability to identify a living individual.

The Advocate General's view

The Advocate General ("AG") took the view that dynamic IP addresses could be classified as personal data. However, the AG noted that this view should be considered in the context of the specific facts of this case. In particular, he highlighted that the German court's question was framed in the context of a third party, the ISP, having additional identifying information.

When is someone identifiable?

The AG adopted an interesting interpretation of one of the recitals to the EU Data Protection Directive. In EU law-making, the recitals provide guidance on how the operative provisions of the Directive should be read and interpreted. The AG focused on Recital 26, which provides that in determining whether an individual is identifiable:

"...account should be taken of all the means likely to be reasonably used either by the controller or by any other person to identify the said person".

Taking a literal interpretation of this, if anyone has the ability to identify the individual, then the information should be considered to be personal data. The AG, however, took a measured approach, forming the view that when determining whether an individual is identifiable, one should consider combining data held by the party in question, in this case, the website operator, and "certain third parties".

What are "reasonable" means?

The AG also analysed another key component of Recital 26, the "reasonableness" of identifying the individual. Generally speaking, it is often difficult to obtain information from ISPs to identify IP access logs. Usually, a court order, a Norwich Pharmacal order in Ireland, is needed. However, the AG took the view that although the ISP could refuse to hand over the data to the service provider, there was still a legal possibility, albeit restrictive, that the data could obtained.

Implication of this Opinion

While these Opinions are not binding, the CJEU often tends to follow them. Here, the AG has adopted a relatively broad interpretation of Recital 26, and therefore of the concept of personal data. The AG's position is significant. He has found that dynamic IP addresses are personal data despite the fact they are only identifiable when combined with ISP-held information. Previously, in EMI & Others v Eircom, the Irish High Court found that IP address logs in the hands of record labels were not personal data.

The AG's view could arguably be confined to the facts of this case. However, if the CJEU were to follow this Opinion, it could lead to a situation where any website that holds IP logs will be required to treat these logs as 'personal data', such as a name and address, and comply with data protection obligations.

What's next?

The court's ruling is scheduled to be published on 19 October 2016. It will be interesting to see if and to what extent the court follows the AG's Opinion.

Many EU regulators already take the view that dynamic IP addresses are personal data, particularly when coupled with other identifying information. The Irish Data Protection Commissioner ("DPC") has recently published guidance regarding the anonymisation and pseudonymisation of personal data. It sets down the DPC's position on what should be considered personal data. We will be examining these views in an upcoming article.

Lastly, it is worth highlighting that IP addresses are expressly viewed as personal data under the EU's incoming data protection law, the General Data Protection Regulation ("GDPR"). With this in mind, the outcome of this case may only have a short-term impact. It is not clear, however, the extent to which dynamic IP addresses, in the hands of someone other than the ISP, might be viewed as personal data under the GDPR. This case could, however, offer guidance on this point.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

To print this article, all you need is to be registered on

Click to Login as an existing user or Register so you can print this article.

Events from this Firm
29 Oct 2019, Workshop, Dublin, Ireland

Our second in-depth training session of 2019 for Company Directors will take place on Tuesday 29 October in our offices on Barrow Street.

Similar Articles
Relevancy Powered by MondaqAI
In association with
Related Topics
Similar Articles
Relevancy Powered by MondaqAI
Related Articles
Up-coming Events Search
Font Size:
Mondaq on Twitter
Mondaq Free Registration
Gain access to Mondaq global archive of over 375,000 articles covering 200 countries with a personalised News Alert and automatic login on this device.
Mondaq News Alert (some suggested topics and region)
Select Topics
Registration (please scroll down to set your data preferences)

Mondaq Ltd requires you to register and provide information that personally identifies you, including your content preferences, for three primary purposes (full details of Mondaq’s use of your personal data can be found in our Privacy and Cookies Notice):

  • To allow you to personalize the Mondaq websites you are visiting to show content ("Content") relevant to your interests.
  • To enable features such as password reminder, news alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our content providers ("Contributors") who contribute Content for free for your use.

Mondaq hopes that our registered users will support us in maintaining our free to view business model by consenting to our use of your personal data as described below.

Mondaq has a "free to view" business model. Our services are paid for by Contributors in exchange for Mondaq providing them with access to information about who accesses their content. Once personal data is transferred to our Contributors they become a data controller of this personal data. They use it to measure the response that their articles are receiving, as a form of market research. They may also use it to provide Mondaq users with information about their products and services.

Details of each Contributor to which your personal data will be transferred is clearly stated within the Content that you access. For full details of how this Contributor will use your personal data, you should review the Contributor’s own Privacy Notice.

Please indicate your preference below:

Yes, I am happy to support Mondaq in maintaining its free to view business model by agreeing to allow Mondaq to share my personal data with Contributors whose Content I access
No, I do not want Mondaq to share my personal data with Contributors

Also please let us know whether you are happy to receive communications promoting products and services offered by Mondaq:

Yes, I am happy to received promotional communications from Mondaq
No, please do not send me promotional communications from Mondaq
Terms & Conditions (the Website) is owned and managed by Mondaq Ltd (Mondaq). Mondaq grants you a non-exclusive, revocable licence to access the Website and associated services, such as the Mondaq News Alerts (Services), subject to and in consideration of your compliance with the following terms and conditions of use (Terms). Your use of the Website and/or Services constitutes your agreement to the Terms. Mondaq may terminate your use of the Website and Services if you are in breach of these Terms or if Mondaq decides to terminate the licence granted hereunder for any reason whatsoever.

Use of

To Use you must be: eighteen (18) years old or over; legally capable of entering into binding contracts; and not in any way prohibited by the applicable law to enter into these Terms in the jurisdiction which you are currently located.

You may use the Website as an unregistered user, however, you are required to register as a user if you wish to read the full text of the Content or to receive the Services.

You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these Terms or with the prior written consent of Mondaq. You may not use electronic or other means to extract details or information from the Content. Nor shall you extract information about users or Contributors in order to offer them any services or products.

In your use of the Website and/or Services you shall: comply with all applicable laws, regulations, directives and legislations which apply to your Use of the Website and/or Services in whatever country you are physically located including without limitation any and all consumer law, export control laws and regulations; provide to us true, correct and accurate information and promptly inform us in the event that any information that you have provided to us changes or becomes inaccurate; notify Mondaq immediately of any circumstances where you have reason to believe that any Intellectual Property Rights or any other rights of any third party may have been infringed; co-operate with reasonable security or other checks or requests for information made by Mondaq from time to time; and at all times be fully liable for the breach of any of these Terms by a third party using your login details to access the Website and/or Services

however, you shall not: do anything likely to impair, interfere with or damage or cause harm or distress to any persons, or the network; do anything that will infringe any Intellectual Property Rights or other rights of Mondaq or any third party; or use the Website, Services and/or Content otherwise than in accordance with these Terms; use any trade marks or service marks of Mondaq or the Contributors, or do anything which may be seen to take unfair advantage of the reputation and goodwill of Mondaq or the Contributors, or the Website, Services and/or Content.

Mondaq reserves the right, in its sole discretion, to take any action that it deems necessary and appropriate in the event it considers that there is a breach or threatened breach of the Terms.

Mondaq’s Rights and Obligations

Unless otherwise expressly set out to the contrary, nothing in these Terms shall serve to transfer from Mondaq to you, any Intellectual Property Rights owned by and/or licensed to Mondaq and all rights, title and interest in and to such Intellectual Property Rights will remain exclusively with Mondaq and/or its licensors.

Mondaq shall use its reasonable endeavours to make the Website and Services available to you at all times, but we cannot guarantee an uninterrupted and fault free service.

Mondaq reserves the right to make changes to the services and/or the Website or part thereof, from time to time, and we may add, remove, modify and/or vary any elements of features and functionalities of the Website or the services.

Mondaq also reserves the right from time to time to monitor your Use of the Website and/or services.


The Content is general information only. It is not intended to constitute legal advice or seek to be the complete and comprehensive statement of the law, nor is it intended to address your specific requirements or provide advice on which reliance should be placed. Mondaq and/or its Contributors and other suppliers make no representations about the suitability of the information contained in the Content for any purpose. All Content provided "as is" without warranty of any kind. Mondaq and/or its Contributors and other suppliers hereby exclude and disclaim all representations, warranties or guarantees with regard to the Content, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. To the maximum extent permitted by law, Mondaq expressly excludes all representations, warranties, obligations, and liabilities arising out of or in connection with all Content. In no event shall Mondaq and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use of the Content or performance of Mondaq’s Services.


Mondaq may alter or amend these Terms by amending them on the Website. By continuing to Use the Services and/or the Website after such amendment, you will be deemed to have accepted any amendment to these Terms.

These Terms shall be governed by and construed in accordance with the laws of England and Wales and you irrevocably submit to the exclusive jurisdiction of the courts of England and Wales to settle any dispute which may arise out of or in connection with these Terms. If you live outside the United Kingdom, English law shall apply only to the extent that English law shall not deprive you of any legal protection accorded in accordance with the law of the place where you are habitually resident ("Local Law"). In the event English law deprives you of any legal protection which is accorded to you under Local Law, then these terms shall be governed by Local Law and any dispute or claim arising out of or in connection with these Terms shall be subject to the non-exclusive jurisdiction of the courts where you are habitually resident.

You may print and keep a copy of these Terms, which form the entire agreement between you and Mondaq and supersede any other communications or advertising in respect of the Service and/or the Website.

No delay in exercising or non-exercise by you and/or Mondaq of any of its rights under or in connection with these Terms shall operate as a waiver or release of each of your or Mondaq’s right. Rather, any such waiver or release must be specifically granted in writing signed by the party granting it.

If any part of these Terms is held unenforceable, that part shall be enforced to the maximum extent permissible so as to give effect to the intent of the parties, and the Terms shall continue in full force and effect.

Mondaq shall not incur any liability to you on account of any loss or damage resulting from any delay or failure to perform all or any part of these Terms if such delay or failure is caused, in whole or in part, by events, occurrences, or causes beyond the control of Mondaq. Such events, occurrences or causes will include, without limitation, acts of God, strikes, lockouts, server and network failure, riots, acts of war, earthquakes, fire and explosions.

By clicking Register you state you have read and agree to our Terms and Conditions