Last updated: 
2 months 2 weeks ago
Blog Manager

We are the Computer Security and Incident Response Team (CSIRT) for the Janet network. Part of Jisc's Security Operations Centre, our mission is to safeguard the current and future network security of Janet (steering the security policies for all Janet connections) and of our customers, creating a secure environment to conduct your online activities. Our primary function is monitor and resolve any security incidents that occur on the Janet network, with specialists tracking a range of platforms, including Unix, Linux and Windows.

Blog Article

Time to move from the mechanics and policy of DNS replication to a new topic. Within the global DNS there are two roles that a server can play: ones that hold data - nameservers, and ones that fetch that data for clients - resolvers. Nameservers need to provide their data to the entire Internet whereas resolvers serve a small set of client systems.

Blog Article

So you've designed your redundant architecture and ensured that your data is being replicated across it? All set? Not quite. Within your DNS configuration there are two timers that we frequently see misconfigured -  TTL values and the SOA expire value.

Frequently we see these left at default a default of one day (86400 seconds). Whilst these may suit many organisations it's worth taking a closer look to make sure that they match your expectation for your DNS services.

Blog Article

Having designed a redundant DNS infrastructure, one of the most common mistakes is failing to ensure that secondary nameservers can successfully replicate data for the domains it is hosting. The most common way this is done on the Internet is though zone transfers - the AXFR command. This command causes a DNS server to reply with all the data it knows for a domain.

Blog Article

When providing DNS nameserver services a degree of redundancy is needed. In most cases the DNS records for a particular domain will be hosted by at least two nameservers, but is that enough by itself?

When building a resilient system the risks involved with the failure modes of the system need to be considered and weighed up against the associated costs and overheads. As a common example - does having both DNS servers on the same local network segment provide you with protection against network failure? Probably not.

Blog Article

As you may now be aware, the FBI and NCA are coordinating 'global day of action' against the Zeus-P2p and Cryptolocker families of malware. Law enforcement and industry partners will be collaborating to interrupt infrastructure vital to the malware's operation and to raise public awareness of these threats.

Blog Article
You can call CSIRT for help
 
If you suspect that your institution is suffering from a DDoS attack you can call on Janet CSIRT for assistance. We can help you understand and analyse the traffic, and in most cases can work with our network operations centre and transit partners to filter traffic. Where possible we work with other network providers to eliminate the sources of the attack.
 
Blog Article

Following on from our messages and briefing at the start of the year, DDOS attacks are continuing to occur at a greater frequency than they have in previous years. We have been working to assist affected customers when they happen.

Many of the attacks make use of unauthenticated UDP based services to reflect and amplify traffic against the chosen target. Open DNS resolvers (53/udp) and increasingly CHARGEN (19/udp) are the two most abused services. It's not unusual to see attacks in the order of 10Gb/s.

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