Since January 1st, a few key milestones have passed, indicating how urgent the IPv4 rundown problem has become. Firms that rely on internet connectivity must take urgent action in light of the events:

• The allocation last week of two further /8s (blocks of IPv4 addresses with the same number before the first dot) to APNIC mean that for the first time, less than just ten percent of the IPv4 unallocated pool is available to be assigned.  At current utilisation rates, this pool will be exhausted in only 600 days.  Of course, the internet could stop growing, but all signs point away from this…
• The allocation of 1.0.0.0/8 is the assignment of the first really ‘dirty’ block of addresses, signalling that we really are in the run-down period.  Bad network design decisions in the past have meant that networks have ‘borrowed’ the use of addresses starting 1. for ‘internal use only’ or special applications on their network.  This means that organisations assigned address space starting ‘1′ may well have partial connectivity even though they are rightfully assigned the space.  Examples are the braindead hotspot operators who take addresses like 1.1.1.1 to trigger hotspot logout, but a handful of examples appear across this address range.
• RIPE NCC, the organisation who assign addresses to networks in and around Europe have this month implemented their ‘run down’ policy which will mean that organisations requesting space will only be able to cater for their growth requirements for a very short amount of time.  This is to evenly spread the inevitable misery across the ISP community.

RIPE members should thoroughly audit their address space so that they can ensure that their records are accurate, because RIPE are more likely to ensure that address space is assigned to your end users in line with the community’s policies.  ISPs and services providers who need help can contact me for further information or specific assistance.

Organisations who rely on internet connectivity for their products should ensure their providers have an IPv6 migration plan in place.  Otherwise end-to-end connectivity for your home or office is unlikely to be something you can enjoy looking beyond the runout period.  Companies hosting network services, for example a website, should enquire what their host’s IPv6 plans are, and start to enable their services via v6.

There is real traction to ensure v6 support appears in both the hardware and services you need to connect to the internet.  It is easier today than before to find help making your services available via v6.  The alternatives – patchy connectivity via nested stacks of ipv4 islands, or no more end-to-end connectivity (so that your internet service is a walled garden), have much worse consequencies than learning to roll v6.

Engineers know the facts by now and have no excuse.  For more information, see the RIPE NCC’s information site, ipv6actnow.

The slides show that the new route-servers perform splendidly well compared with traditional Quagga based MLPs, also that route-servers are now free of ‘first generation code’ bugs, and also that they handle your prefixes transparently – as you would expect.

Interestingly, BIRD and OpenBGPd behave identically ‘on the wire’ so IXPs are encouraged to use multi-vendor MLP on their platform for increased reliability and stability.  The new breed of route-server code is dependable and tested, so networks that would like to connect should draw confidence from this testing, and IXPs wishing to roll out MLP services should feel confident in the software tested.

Happy peering!

Would domain name users who are concerned about the accuracy of data served pay extra for the ability to sign their DNS zone ?  A handful of people in the room raised their hand in agreement, but the overwhelming majority of operators did not.

His argument was that this compared well with SSL certification authorities who sell certificates that suggest that visitors to a website are interacting with a validated entity, and the technology guarantees privacy between the visitor and the website.  It’s this technology which makes buying and selling online safe.

However, I think that DNSSEC has different aims altogether – simply to guarantee that DNS data is not changed en-route between the authoratative server, through the caches, all the way to users.  Therefore there are significant attack mitigation reasons to deploy DNSSEC, so I hope that operators will begin trials (we are doing so), and that the pace of trials will quicken as the root zone will be signed this year.

If DNSSEC is deployed as designed, then temporary and brief mistakes will not be imported into DNS caches, users will not fall foul to tampered data in caches, and we all receive an authenticated/secure channel for distributing DNS data inside an organisation.

The argument that Dr. Schweiger used is that DNSSEC adds an operational and technical burden to registries (extra communication with registrars, more complex software, additional CPU and bandwidth requirements).

I hope that my colleagues in other organisations agree that there are significant infrastructure advantages to freely allowing DNSSEC to grow, and that Moore’s Law, automation, and the fact that DNS registries normally find it simple to peer widely with ISP networks will offset the needs to consider the commercial signing model.

The messages are clear and simple.  Working now to get ready for the IPv6 transition will be less expensive and lower risk than waiting for IPv4 starvation to hurt.  I interviewed some key enterprises about their specific grumbles but the great news is that most are transitional and already people are working on fixing them.

They all show that the effects of scarsity of IP addresses will be felt before the final few addresses become assigned to end users.  All consumers of addresses will feel constrained, which means all businesses trading online, whether they are a traditional ISP, a growing e-commerce shop, or a datacentre/hosting firm.  The policies under consideration are :

• 2008-06 – Both new and existing organisations requesting IPV4 addresses shall be given addresses only to support transitioning technologies (i.e. infrastructure services which enable access to IPv6 addressed resources.)  They will only be given one block of IPv4 addresses, and this shall be the smallest possible range of addresses as decided by the community at large.  This is the only range of addresses which shall be given to the end user, even if their needs justify more.
• 2009-03 – From summer 2010, any organisation shall only be given enough new addresses to cater for anticipated need for nine months.  By summer 2011, this will change to three months.  Organisations (registries and end users) MUST have used more than half of their address space within six months of assignment or allocation.
• 2009-04 – Organisations must demonstrate that they are implementing an IPv6 transition policy (RFC5211) in order to be given IPv4 addresses.  Allocations from the RIPE NCC will be /27 (32 addresses for the entire registry, e.g. ISP)

This also means that the effects of black market trading in address space will be seen before the ‘anticipated’ IPv4 dry date in 2011.  There are no magic bullets, you (and your customers, suppliers, and partners) need deep pockets, decades worth of existing resources, or an ipv6 transition plan.  The only sensible option is to plan your v6 deployment today.

I decided to put the timetable to the test.  On Wednesday at 2:30PM uk time, I applied for a /32.  One hour later, we were allocated 2a02:c30::/32.  I straight away assigned a /48 for our network infrastruture, and another for our production hosting lan, another for our development hosting lan.  From these /48s, several /64s were reserved, one for router loopbacks, another for point to point links, more for individual hosting applications.  An hour later, this was implemented on our network – routers had loopbacks, and a v6 IGP was up and running, and working.  I filed a ticket with our upstreams, and the first announcement was turned up minutes later – check BGPlay for exact times.  Around 2 hours after making our application to RIPE, we were participants on the IPv6 internet.

Now this is not a front-to-back implementation, but in just two hours we had something to hand over to our systems teams for testing and training.  If you rely on the internet for your business, this is the stage you need to get to urgently.  In fact, by close of play Wednesday, some of our simpler services were already running dual stack, and additionally we are now running Dual-stack for DNS – Nominet having the simplest method for adding ipv6 glue.

Full disclosure: In reality our v6 rollout started months ago, by monitoring advice on operational mailing lists, attending v6 seminars, and in fact we had been engaged in the rollout of ipv6 on several customer networks to date, so this rollout was not frightening for us.

We are now in the position that we can integrate IPv6 addressing as part of every configuration refresh or maintenance on our services, so that v6 is rolled out in a controlled, monitored, and careful manner.  By moving now, we have bought ourselves time – a luxury, and firms waiting longer to start their v6 rollout will have a harder time, with the whole migration feeling like a ‘y2k bug’.

It covers :

• Provisioning tools/notes
• SNMP
• NetFlow notes
• Scripting notes

Some history in very brief terms – all networks on the internet that participate in BGP need a number to identify themselves.  On the public internet, this number normally needs to be globally unique.  The number can be between 1 and 65,535, and we have close to 50,000 of these numbers in use.  To grow past this number, the BGP standard needs to be modified.  The modification is described in a document called rfc4893, and this document was accepted by the community last May.

The first incarnations of router software that support these large AS numbers is now circulating. Due to flaws in the standards that exist in January 2009, if you install one, you may become disconnected from the internet.

Why? Some more background, first: BGP allows for large networks to configure ‘hints’ in their router configuration, by dividing their network into several small networks (confederations).  The information about the ‘virtual’ divisions of the network should be removed from the BGP messages which are sent to other networks, but if a network supports large ASN in some parts, and not in others, the routers in the legacy part of the network may not know to test the ‘large number’ section of a BGP message for the presence of an internal confederation ID.  The standard tries to take this into account by explicitly forbidding that confederation ID be passed between networks in the asn4 part of the BGP message.

However, should this occur by accident, what are the effects?  Well, elsewhere in the Large ASN standard, it states that the connection between two networks should be severed if Confederation ASN appear to be leaked in the ASN4 part of the BGP message.  This means that networks which do not understand large ASN can forward a broken message to a network which does understand large ASN.  At which point the network which does understand large ASN should tear down the session.

Since this message can be delivered over a transit session, this means the receiving ISP loses their connection to the internet via that ISP.  If it learns the router over every ISP, then the network can lose its connection to the internet entirely.

The message that I reported was leaking in December is still leaking.  AS196629 (AS3.21 in legacy asdot notation) is announcing to AS35320, who are not stripping their confederation information from the large-asn section of BGP messages.  If you learn the prefix via AS196629’s other transit, AS6886, then you are fine.  If you learn the prefix via AS35320, you are (today) receiving a broken message.

We tested out how Cisco IOS is coping with this broken message using the first generation of code for the cisco 7200 router that understands ASN4.  We peered the router to NetSumo’s research and development network, AS15653.  Cisco honours the standard/rfc, and breaks the session.  Since it learns the dirty message on the transit session, the router disconnected our test network from the internet entirely :

• *Jan 16 11:29:58.531: %BGP-5-ADJCHANGE: neighbor 193.239.32.2 Up
• *Jan 16 11:30:02.595: %BGP-6-ASPATH: Invalid AS path (65044 65048 65062) 3.21 23456 received from 193.239.32.2: Confederation found in AS4_PATH
• *Jan 16 11:30:02.595: %BGP-5-ADJCHANGE: neighbor 193.239.32.2 Down BGP Notification sent
• *Jan 16 11:30:02.595: %BGP-3-NOTIFICATION: sent to neighbor 193.239.32.2 3/1 (update malformed) 27 bytes E0111803 030000FE 140000FE 180000FE 26 FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF 0050 0200 0000 3540 0101 0240 020C 0205 3D25 2114 89F8 5BA0 5BA0 4003 04C1 EF20 02E0 1118 0303 0000 FE14 0000 FE18 0000 FE26 0202 0003 0015 0000 5BA0 175B CFDA

If you work in this field, I implore you to read the more thorough analysis on the nanog list, and participate in the discussion to work out how we should correct the standard, to allow routers to behave differently when a dirty message is received.  If we do not, then there is a simple, easy to understand, and easy to implement mechanism to break the internet, as soon as networks upgrade to the current version of their routing software.

Firstly, I like the Bounce handling and web-interface to Mailman, so this is why I don’t just run Majordomo for lists any more.  Its worth pointing this out, in case you wonder why I still use tool B, even though I have to do lots of work to make it work like tool A !

After running newlist, I recommend the following configuration changes (defaults which are changed assume you are running the Debian packaged Mailman) :

• General Options – make the administrators email address a role account that you will not subscribe to the mailing list. This is basically so that if you bounce an administration message from Mailman, due to your spam filters or an error, Mailman wont decide to unsubscribe you from the mailing list!  I have had this happen to me before when I used to hand-check spam directed at uknot.
• Decapitalise public name of the list – to make it look neater, and more like the output of the ‘lists’ command in majordomo.  Don’t forget to decapitalise the subject line tag if you do this.  I also tend to make the subject line tag very small so that on little displays, it’s still possible to scan a folder and read threads of interest on subject alone.
• Disable monthly reminders – they are really annoying to your subscribers, and Debian’s default position is disabled, but some implementations do not disable subscription reminders.
• My users get confused by the Filter out duplicate messages to list members option.  When a list subscriber is cc:d to a list post, users tend to expect to see a copy of the mail in their inbox, and their mailing list archive.  I turn the filter off so that this happens.
• I tend to enable the Should administrator get notices of subscribes and unsubscribes option, so that I can track whether promoting a list in a certain place has worked!
• In “Non Digest options”, if I am migrating for a Majordomo list, I empty the box for message footer, and also tend to remove it when its a geek mailing list, as to most high volume mail readers, its obvious when an email has been posted to a mailing list, because its filtered into the correct mailbox !  For low volume lists that are intended for low volume mail readers, the footer might be useful.
• Check the reply to option, so that mailing lists that are intended to promote on-list discussion have a header that directs conversation back to the list, and mailing lists that will yield a high proportion of off-list mail do not have this header.
• Be slightly annoyed with me that the only English option in ‘Language Options’ is English (USA) when there is no English (UK).

Happy list-administration!

And you may find the following lists interesting to your work :

• mailop, for those who work in the field of mail systems administration.
• experts, for those who work in expert e-commerce roles.
• uknof, for those who work in network engineering roles, or systems/ISP environments.

I disagreed on the grounds that unicast IP is a fairly bad way to broadcast large volumes of data.  When wrapped with TCP to guarantee delivery and ensure quality, the infrastructure to handle the volumes of viewers for major tv series or live events, makes it hard to imagine it being possible to deliver real-time internet TV. This is before we consider the bandwidth requirements for high-definition video and audio.
So why the change of mind ?

I previously assumed internet delivery was the Raison d’etre for Net Video.  Its not.  The internet might not have proved itself as the most viable platform for broadcast video, but it has proved itself time and again as the perfect platform for publishing content.  Internet TV is going to mean that “TV” gets some of the “wisdom of crowds” treatment, and that organisations with interesting things to say will be able to launch video content to worldwide audiences.  Previously, content makers would have needed to work with a huge machine of tens of organisations before video hit the airways, and they’d need to work with hundreds if they wanted to distribute to a worldwide audience.  Today ?  All you need is a bit of content, a bit of tallent and some hosting.

The second benefit to internet video is how portable it is.  I have syndicated three shows from Revision3 (Diggnation, Systm, and Scam School), Scobleizer TV, and some other geeky video stuff.  It is downloaded to my laptop, and copied to my iPhone.  I can watch this on a normal TV at home in high quality, via a cheap phone to tv cable, or on the move via laptop or phone.  I can watch my usual TV if I am staying away by plugging the phone into a tv in a hotel room.
In the future, I expect to watch niche stuff that is downloaded, and popular things that are spooled to disk via a broadcast system.  I would like to see some really neat devices shipping this year which allow me to combine recorded broadcast TV with downloaded Internet video, and let me carry broadcast TV in the same portable manner.

Also would love to hear what internet TV people are watching via the comments on the blog!