Daniel Karrenberg

Daniel Karrenberg

Chief Scientist at the RIPE NCC
Joined on February 28, 2008
Total Post Views: 247,461


Daniel Karrenberg is chief scientist at the RIPE NCC, the regional Internet registry for Europe and surrounding areas.  He directs research, creation and piloting of new services as well as general strategy development.

Karrenberg has been helping to build the Internet in Europe from its very beginnings.  In the 1980s he has helped to build EUnet into the first pan-European ISP.  In the 1990s he has helped to build RIPE and the first regional Internet registry: the RIPE NCC.  Karrenberg has served as the first CEO of the RIPE NCC until 2000 when he became its first chief scientist.  In 2001 his contributions to the development of the Internet have been recognised with the Jonathan B. Postel service award. 

A computer scientist by training, Karrenberg likes to invent, design and implement Internet related systems, especially those collecting and processing data about the Internet itself.  He also likes to occasionally inject physics, engineering and “networking style” into debates about Internet governance.

Except where otherwise noted, all postings by Daniel Karrenberg on CircleID are licensed under a Creative Commons License.

Featured Blogs

IPv4: Business As Usual

This year, we expect that the RIPE NCC's pool of unallocated IPv4 addresses will reach the "last /8", meaning that we have 16,777,216 IPv4 addresses left in the available pool. At that point it will no longer be possible for RIPE NCC members to obtain the amount of IPv4 addresses they will require to expand their current and future networks. When we hit the last /8, the RIPE NCC will only be able to distribute IPv6 addresses and a one-off allocation of IPv4 address space... Has this caused a last minute rush? more

Measuring Root Server Performance

Root name servers are a core service of the Internet. As such they receive a huge amount of queries and need to answer reliably with acceptable delay. The RIPE NCC is responsible for operating one of the 13 DNS root name servers K-root which responds to 10,000 - 15,000 queries per second. Most root servers are operated as a network of distributed "instances" using anycast. more

No Big Run on IPv4 in 2011

2011 was an interesting year for IPv4: in February 2011, the Internet Assigned Numbers Authority (IANA) handed out their last free IPv4 address blocks to the Regional Internet Registries (RIRs). In April 2011, the APNIC (the Regional Internet Registry for the Asia Pacific region) started allocating from its last /8. At the RIPE NCC we did not see a big jump in IPv4 address allocations in 2011, as anticipated by some observers. more

DNS Measurements with RIPE Atlas Data

As described in New RIPE Atlas Features in the Making, each RIPE Atlas probe performs "anycast instance discovery" measurements. This means, for each DNS root name server, we determine which instance of a name server a probe uses. We compile the data from all probes and build maps showing these results for each Atlas probe. In other words, the map shows the "gravitational radius" for root DNS server instances. more

Visibility of Prefix Lengths in IPv4 and IPv6

Internet routes are specified for an address prefix. The shorter the prefix, the more general the route. A shorter prefix covers more address space and thus a bigger part of the Internet. Very long prefixes cover few addresses and are used for local routing close to the destination address. In general, it is not necessary to distribute very long prefixes to the whole Internet, because a more general, shorter prefix is sufficient to direct packets in the direction of the destination. more

DNSSEC Takes Off in Wake of Root Zone Signing

The Domain Name System Security Extensions (DNSSEC) is a suite of IETF-developed specifications designed to validate information provided by the Domain Name System (DNS). ... When the root zone was signed in June 2010, this acted as a catalyst for TLD operators to deploy DNSSEC on their side. We have seen a gradual but significant increase in signed TLDs since then. The map in this post shows the level of DNSSEC deployment in Europe. more

Measuring World IPv6 Day - First Impressions

The RIPE NCC took active measurements of World IPv6 Day participants before, during and after World IPv6 Day (in cooperation with CAIDA). We selected 53 participants and performed periodical A and AAAA DNS lookups and HTTP fetches from 40 servers worldwide. For HTTP, we fetched data over IPv4 and IPv6. These provide important control points... more

Internet Service Quality Measured from Thousands of Locations

RIPE Atlas, the new active measurements network maintained by the RIPE NCC, gives you a way to easily measure the quality of your Internet services. RIPE Atlas is designed in such a way that it can collect data for analysis from a great number of locations on the Internet. The actual measurement devices, or "probes", are so small that they can be easily deployed in a home environment. more

IPv6 RIPEness: One Year Later

A year ago, the RIPE NCC introduced IPv6 RIPEness -- a system that rates IPv6 deployment of Local Internet Registries (LIRs)... Now, one year later, the numbers have gone up... In absolute numbers: more than 3,000 LIRs have IPv6 address space. This means that the RIPE NCC has made more than 1,100 IPv6 allocations within 12 months. more

Amount of Unsolicited Internet Traffic Reflecting Situation in Libya

During the recent political unrest in the Middle East, researchers have observed significant changes in Internet traffic and connectivity. Typically people look at routing data, latencies when connecting to sites and search and query statistics. Here we show results from a previously unused source of data: unsolicited Internet traffic arriving from Libya. The traffic data we captured shows distinct changes in unsolicited traffic patterns since 17 February 2011. more

How a Routing Prefix Travels Through the Internet

What happens when an IP address prefix gets announced or withdrawn. How does this information propagate through the Internet? And how does it affect the amount of Border Gateway Protocol (BGP) traffic across the Internet when a single prefix is freshly announced or withdrawn from the global routing table? The following short analysis shows the detailed effects of these two events. more

The ISP Industry and the Financial Sector - Amazing Similarities

In the last RIPE Labs article on this subject How Does the Internet Industry Compare?, we looked at ways to compare our industry with other industrial sectors, and identified a number of characteristics that an industry must have in order to be comparable to the Internet industry. It seems the financial sector or monetary credit industry shares many of these characteristics and in fact behaves much like the Internet industry. more

How Does the Internet Industry Compare?

In an earlier CircleID post (The ISP Industry: Concentrated or Diverse?) we discussed if the ISP industry is concentrated and concluded the industry is amazingly open and varied. This time we try to identify criteria that make other economic sectors comparable to our own industry, using the global automotive manufacturing sector as an example to test our assumptions. Comparing the Internet industry with other industries is interesting, because it is quite special in a number of ways: it is transparent, keeps detailed records and values a high level of industry self-regulation. It also enables organisations to serve a global market. more

The ISP Industry: Concentrated or Diverse?

In August 2010, we looked at the growth in RIPE NCC membership and concluded that the number of new RIPE NCC members is still growing at an amazing pace, even during the recent economic downturn... This time we are looking at the different sizes of RIPE NCC members over time. It is often claimed that there is massive consolidation happening in the ISP community, especially in times of economic difficulties like in the early 2000s and now. We were curious to find out if this is really the case. more

DNS Clients Do Request DNSSEC Today

After the DNS root zone was finally signed and a number of Top-Level Domains (TLDs) began signing their zones, we were curious to see how many clients actually request DNSSEC information. We looked at the RIPE NCC server that provides secondary service to several country code top-level domains (ccTLDs). more

Internet Continues to Grow at Astonishing Pace (Perspectives from RIPE NCC Membership Stats)

We are at the height of vacation season here in the Netherlands, and the RIPE NCC headquarters in Amsterdam are quieter than usual. The downtime has given me a chance to reflect on how the recent economic downturn has affected our membership growth. The good news is that it hasn't. more

A Look at IPv6 Allocations Since 1999

In the previous graph and article published here two weeks ago, we showed that many ISPs in the RIPE NCC service region (Europe, the Middle East and parts of Central Asia) have not yet obtained IPv6 addresses from the RIPE NCC. Our latest graph demonstrates just how quickly this is changing. more

IPv6 “Ripeness”: The Hard Numbers on ISPs and Deployment Rates

As the unallocated IPv4 address pool runs out, are Internet Service Providers (ISPs) actually deploying IPv6? The graph, first in a series from RIPE Labs, looks at the IPv6 "ripeness" of all ISPs registered as RIPE NCC members. We created a rating system that gives ISPs up to four "stars" for IPv6 services that they provide, based on the following criteria... more

RIPE NCC Publishes Case Study of youtube.com Hijack

As you may be aware from recent news reports, traffic to the youtube.com website was 'hijacked' on a global scale on Sunday, 24 February 2008. The incident was a result of the unauthorised announcement of the prefix and caused the popular video sharing website to become unreachable from most, if not all, of the Internet. The RIPE NCC conducted an analysis into how this incident was seen and tracked by the RIPE NCC's Routing Information Service (RIS) and has published a case study... more

Topic Interests

DNSIPv6 Transition IPv4 MarketsAccess ProvidersRegional RegistriesCybersecurityThreat IntelligenceDNS SecurityNew TLDsNetworksInternet ProtocolRegistry Services

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Popular Posts

How a Routing Prefix Travels Through the Internet

IPv6 “Ripeness”: The Hard Numbers on ISPs and Deployment Rates

IPv6 RIPEness: One Year Later

DNSSEC Takes Off in Wake of Root Zone Signing

RIPE NCC Publishes Case Study of youtube.com Hijack