Author: Michael Lucas

Writer. Sysadmin. Owns this site.
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FreeBSD devsummit virtualization session

Some notes from the FreeBSD virtualization devsummit. Very rough, but my understanding is very rough, so all is as it should be.

Bhyve moving to UEFI loader away from FreeBSD and grub2
• Fork of intel EDKII (BSD License), OVMF build target
• For bhyve instead of Qemu
• Includes CSM BIOS emulation for non-EFI aware OS’s
• Currently in-house, being moved to public git repo
• Buildable on FreeBSD (GCC 4.6 or later), needs to be a port – bhyve folks need port creation help
• Serial console only: working on VGA emulation with VNC client

Networking:
• Virtio doesn’t support modern networking features
• One NIC, e1000 ((multiq, jumbo frames, TSO) under way
• e1000e (82580) dev emulation in progress
• each has thousands of registers, still working on them

Considering:
• user mode using WANProxy/libuinet
• simple kernel eth switch

Storage
• zvol GEOM-avoidance in place (mav@) – prevent geom from sniffing ZFS partition tables, so host will never see VM filesystem
• virtio todo: asynch block writes, add virtio SCSI
• Wanted: BSD-licensed sparse image tools for working with vmdk, qcow2, vhd, etc. Would be nice to point bhyve at a VMDK file and so “go!”

Future
• AMD-SVM
• Windows guest support (requires UEFI)
• Illumos doesn’t need UEFI, needs a real BIOS – use BIOS compat in UEFI
• ARM(64) chips have virtualization support, get bhyve to work on it.
• Save state/restore/migrate
• configuration file, as the command line is unwieldy for hierarchical info – use UCL because the ports people also use UCL
• Regression suite – bhyve supports lots of different hardware and operating systems, so we need to have automated testing

Other virtualization
• Virtualbox – FreeBSD is tracking very closely, 4.3.10 came out 25 March, port updated on 28 March.
• HyperV – 10.0, amd64 and i386 guest support

o Recent Azure image announcement
o Nobody in the FreeBSD community tracks Hyper-V, it could use a nanny

Luigi Rizzo on performance with device drivers
• One option – e1000 emulation, performance will be poor, will be slow
• Some emulation drivers fake TSO, etc
• No good solutions outside paravirtualization
• High performance = modify guest device driver to be virtualization-aware
• Luigi got 17GB/s using netmap with bhyve

Roger Pau Monne’ on Xen
• Changes in FreeBSD 10

o Vector callback for injecting event channel interrupts
o PV timer
o PV IPIs
o Add Xen support into GENERIC – can now use freebsd-update
o Sponsored by SpectraLogic and Citrix

• PVH domU

o Supported guest mode since 4.4
o Builds atop of the PVHVM work introduced in FreeBSD 10
o Half-merged into –current, some work remains
o Same speed as PVHVM, main difference is way it boots
o Not as intrusive as a traditional PV port

• PVM Dom0

o Xen side patches almost fully merged
o Main difference between PVH DomU and Dom0 is that on Dom0 FreeBSD needs to manage the hardware
o Add support for PIRQ (physical interrupts routed atop event channels)
o ACPI tables parsed by Dom0, and Xen must be made aware of the underlying devices
o Xen user-space control devices needed by the toolstack:

 Privcmd – allows issuing hypercalls into Xen and mapping foreign domain memory from userspace
 Evtchn – allows registering and receiving interrupts by user-space applications

• Big items remaining

o Add multiboot support to the FreeBSD bootloader – right now, you must use pxelinux or grub
o Improve if.xn – doesn’t work correctly with a NetBSD dom0, doesn’t work properly between guests on the same host, paravirtualized interface does not perform well yet.

• Hoping to have Xen work for FreeBSD 11

VirtIO/VMWare guest drivers by Brian Venteicher
• Work done over last year
• VirtIO: new

o Unmapped IO – block and SCSI
o Network multiqueue
o Random (entropy) device
o Initial console driver –can do multi-consoles, hotplug is so-so

• VirtIO: remaining

o Support missing devices – MMIO
o Non-x86 architectures
o SCSI multiqueue
o VirtIO version 1 specification – very similar to existing virtio

• VMWare

o Vmxnet3

 Vmware provided driver, messy
 OpenBSD imported their own vmx driver May 2013
 Ported to FreeBSD 10.0

• TSO/LRO offload
• Multiqueue

 To do: PVSCSI & VMWare tools

Device emulation in bhyve

• Most emulated in userspace usr.sbin/bhyve
• Kernel ones in vmm/io/ (PICs and timers)
• ISA-LPC – uart, rtc
• PCI

o Virtio

 Block – storage
 Net – tap
 Rng – random entropy from /dev/random

o Ahci
o Pass-through

• Go through how virtio device drivers work. Interesting, lots of diagrams he should post, but way above my head, so I didn’t take too many notes
• Virtio random number generator

o Usr.sbin/bhyve/pci_virtio_rnd.c
o Guest rng driver requests 32-bit number to replenish its random pool
o FreeBSD /dev/random is non-blocking, using Yarrow and (soonish) Fortuna

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FreeBSD 11 feature goals

I’m at the BSDCan FreeBSD devsummit, and the current topic is FreeBSD 11 Goals.

As the Great Committer John Baldwin has requested that people take notes and blog about the discussions, and this might be of wider interest, here’s the goals.

These are my notes. I probably missed things. I would be shocked if I didn’t, actually. And I probably misunderstood some stuff.

Test suite/QA (jmmv) – some stuff merged to 10
Mips64 & more MIPS stuff
Scatter/Gather mbufs (scottl) – collapse down mbufs from a long chain into one unit
Lldb (emaste) – make it first-class citizen, fully functioning & working in 11 on all platforms, native cross-platform debugging
Uefi boot and install support (emaste)
Package the base system (gjb/bapt)
Open to floor:
AES GCM added to ipsec – jmg
ASLR – Shawn “The Goats Are His Fault” Webb
DNS improvements – Erwin
Suspend/resume
Libc++
OpenMP
FreeBSD devs – Want icc? Talk to gnn@
Kload – hot swap kernel upgrade
Dragonfly mailer as default
Ncurses cleanup
Capsicum and casper improvements – use casper to help apps use dnssec correctly
TCP performance and enhancements (gnn) – project as a whole needs broader TCP patch reviewers
L2 rework
Libuinet
Arm64 (andyt)
Package building Mips32 packages via qemu
External toolchain improvements (imp) – some people need GCC
Remove gcc by 11 – gnn willing to remove it right after this devsummit session
Remove ia64 (marcel)
Useland dtrace (marki)
Xen dom0 for x86 (rogier)
Kqueue64 from osX – available from Apple, we could pull this in (jmg)
Async sendfile (glebius)
Lightweight reference counts (maybe) (glebius)
Kdbus (need for desktop)
Vt + newcons default (emaste)
KMS, DRM, AGI impromements (dumbbell & kip)
SMT (need)
Encrypted kernel dump (gnn)
Nand flash (warner)
Superpages for certain arm & mips
Multi-endian ufs
Libdispatch (sson)
Move libraries to private (need, bapt, bdrewery help)
/etc/src.conf improvements
64-bit linuxulator
newer linuxulator (xmj)
new autofs (emaste)
unionfs improvements (need)
64-bit struct stat & dirent, mount_pathlen, max_pathlen, (benno)
X32 – alternate abi for amd64 – jhb wants, but no commitment
PF – improve its internal API so we can manage stable branches, merge newer version, IPv6 improvements (glebius)
Bhyve – UEFI
Vxlan
Reproducible release builds – remove usernames, host names, timestamps from builds
IPv6 security improvements
Network stack backpressure
Network multipath (stretch goal)
Capsicum shell – will sandbox package building
Non-root image building

Will all this happen? Who knows. But plans are nice.

Posted on

My NSP ebooks, 50% off

Today is International Day Against DRM.

All No Starch Press ebooks are available at 50% off. The titles include:

  • Absolute OpenBSD
  • Network Flow Analysis
  • Cisco Routers for the Desperate (both editions, I’d recommend the 2nd)
  • PGP & GPG
  • Absolute FreeBSD

    Plus books by other authors, of course. Once you’ve bought all of mine, check them out too.

    Use coupon code RIGHT2READ to get the discount.

    For the record: all of my books[1] are published without DRM. In my opinion, once you buy my book it’s yours to do with as you please. I trust my readers.

    Yes, unlicensed downloaders discourage me from writing tech books. On the other hand, the shocking number of people who seek out and use my poorly advertised tip jar encourage me more than the illicit downloaders discourage me.

    1: I lie about being 100% DRM-free. I have one short story with DRM, because I didn’t notice the DRM checkbox when I put it on Amazon. The only way I can remove DRM is to un-publish and re-publish the piece. If I do that, I lose all the nice reviews it’s gotten. Fiction reviews are hard to come by, so I chalk this up to the learning curve and move on. But if you buy that story, and you strip the DRM, I really won’t mind in the slightest.)

    • Posted on

    Penguicon 2014 Schedule

    “Hey, where is Lucas? Why hasn’t he posted lately?”

    I’ve done nothing worth posting about. Most of this month I spent removing a per-millennial switch from the core of the network, which was painstaking and annoying but not noteworthy. I then spent nine days at a writing workshop, which was fascinating, educational, and utterly exhausting. I could argue that the workshop was worth blogging about, but I was too busy writing to waste time writing. If you’re interested in writing, though, and you have a chance to do any of Dean or Kris’ workshops, go.

    So:

    Next weekend, I’ll be at Penguicon, appearing on various panels. You can see me at the following one-hour events.

    Friday

  • 5PM: BSD Operating Systems, a Tour – What it says on the label

    • Saturday

  • 11AM: Sudo – You’re Doing It Wrong – Why your popular sudo configuration is incorrect, and how to do it safely
  • 1PM: Copyright versus Free Information – What happens when the concept of ‘information can’t be contained’ clashes with content creators who want monetary recompense for their hard work? Speakers include:Michael W. Lucas, Shetan Noir, Eva Galperin, Cory Doctorow
  • 6PM: SSH Key Authentication Tutorial – If you’re not doing SSH key authentication, show up here.
  • 8PM: Self-Publishing 101 – Do you? Should you? Various tools and techniques and recommendations.

    • Sunday

  • 2PM: DNSSEC in 50 minutes – How DNSSEC works, and why you should care

    Now if you’ll excuse me, I have a whole great big heap of slides to do…

    • Posted on

    Book Review: “Applied Network Security Monitoring”

    Chris Sanders kindly sent me a review copy of Applied Network Security Monitoring, written by Sanders along with Jason Smith, David J Bianco, and Liam Randall. It’s a very solid work, with much to recommend it to IT people who either have been told to implement security monitoring or who think that they should.

    Some of Applied Network Security Monitoring will be very familiar to anyone who has read any other security book–I’ve read many times that risk equals impact times probability. Every book on this topic needs this information, however, and Sanders and company cover it in sufficient detail to ground a probie while letting the rest of us easily skim it as a refresher.

    Then they take us through selecting data collection points and how they make decisions on where to collect data and what kind of data to collect. Ideally, of course, you collect full packet data everywhere, but in my semi-rural gigabit ISP world I don’t have enough electricity to spin that much disk. Where can you get by with session data, and where do you need full packet capture? ANSM takes you through the choices and the advantages and disadvantages of each, along with some guidance on the hardware needs.

    Data is nice, but it’s what you do with the data that makes security analysis interesting. ANSM uses Security Onion as an underlying toolkit. Security Onion is huge, and contains myriad tools for any given purpose. There’s reasons for this–no one NSM tool is a perfect fit for all environments. ANSM chooses their preferred tools, such as Snort, Bro, and SiLK, and takes you through configuring and using them on the SO platform. Their choices give you honeypots and log management and all the functionality you expect.

    Throughout the book you’ll find business and tactical advice. How do you organize a security team? How do you foster teamwork, retain staff, and deal with arrogant dweebs such as yours truly? (As an aside, ANSM contains the kindest and most business-driven description of the “give the arrogant guy enough rope to hang himself” tactic that I have ever read.) I’ve been working with the business side of IT for decades now, and ANSM taught me new tricks.

    The part of the book that I found most interesting was the section on analysis. What is analysis, anyway? ANSM takes you through both differential analysis and relational analysis, and illustrates them with actual scenarios, actual data. Apparently I’m a big fan of differential diagnosis. I use it everywhere. For every problem. Fortunately, Sanders and crew include guidelines for when to try each type of analysis. I’ll have to try this “relational analysis” thing some time and see what happens.

    Another interesting thing about ANSM is how it draws in lots of knowledge and examples from the medical field. Concepts like morbidity and mortality are very applicable to information technology in general, not just network security monitoring, and adding this makes the book both more useful and more interesting.

    Applied Network Security Monitoring is a solid overview of the state of security analysis in 2014, and was well worth my time to read. It’s worth your time as well.

    postscript

    Not long ago, I reviewed Richard Bejtlich’s The Practice of Network Security Monitoring. What’s more, I have corresponded with both Sanders and Bejtlich, and while they aren’t “help me hide a body” friends I’d happily share a meal with either.

    The obvious question people will ask is, how does Applied NSM compare to tPoNSM?

    Both books use Security Onion. Each book emphasizes different tools, different methodologies, and different techniques. Practical NSM shows Bejtlich’s military background. While Sanders has worked with the military, Applied NSM reads like it’s from an IT background.

    I can’t say either is a better book. Both are very very good.

    Personally, I have never implemented any plan from a book exactly as written. I read books, note their advice, and build a plan that suits my environment, my budget, and–most importantly–my staff. Reading them, I picked between tools and strategies until I found something that would work for my site. Security monitoring is a complex field. Maintaining, let alone building, a security monitoring infrastructure requires constant sharpening of your skills.

    I recommend anyone serious about the field read both books.

    Posted on

    The Con is a Lie

    I hadn’t planned to post this, but enough people asked me that I feel obliged to explicitly state:

    DetroitBSDCon is a joke. So is Oracle buying BSDCan. I did not play off of Dan’s posting: we planned it together, as well as the resulting fight on Twitter. (I must concede that Dan won the Twitter argument by enlisting Randi Harper for Oracle BSDCan. Nobody can stand against @freebsdgirl‘s awesome social networking mojo. Mind you, Dan has absolutely no clue about how we do things here in Detroit.)

    I don’t expect anyone to believe anything posted anywhere on 1 April. Dan and I did not expect to fool anyone, but we did find the idea funny. And so did a lot of other people, so that’s okay. A few folks hate 1 April in general, but they’re not going to change the world. I won’t do gag posts on random days–unless, of course, something is laugh-so-hard-you’ll-herniate-yourself funny and must go on a certain day as part of the joke.

    I’ve done three 1 April gags: this one, the Great Committer in 2011, and FretBSD (also with Dan) in 2003. I only do them if my inspirational muse kicks me in the head.

    A surprising number of people contacted me about DetroitBSDCon — not because they believed it, but because they want me to do it. They don’t care if I hold it in an abandoned factory, they just want DetroitBSDCon to happen. I have run conferences before, but these days I lack the time, energy, and flexibility to do so. Plus, it fails the WIBBOW test. Like, utterly fails the WIBBOW test. Fails with screeching and tears and thrashing about on the ground, running from the test room bawling like a whipped piglet.

    Holding a conference is easy. A lot of work, but it’s very straightforward work.

    If you want a BSD event in your city, here’s what you do.

  • Start small. Try a one-day event, like NYCBSDCon. If you’re successful, up it to two days next year.
  • Find space and a date. The space needs chairs, a screen for slides, projection gear, and clear lines of sight for attendees. mug.org rents a really nice space in the Farmington Hills library. NYCBSDCon found a restaurant with a screen. BSDCan sucks half a dozen rooms off of a university. EuroBSDCon takes over part of a hotel. Space can be expensive, but it doesn’t have to be.
  • Get the date well ahead of time, so people can plan ahead. Don’t overlap a big BSD event.
  • Get speakers. Local speakers are good. Try to coax a couple “big names” into making the trip, sure, but having locals helps make it your conference.
  • Food. People will want to eat. Either have lunch brought in (tricky), or identify the local restaurants that don’t suck. Talk to the restaurant managers before the event; they might do a special rate for a large group at a predictable non-peak time, or at least staff up to handle a flood.
  • Figure out how much all of this costs. Divide by the number of attendees. Double it. That’s your admission rate. Every plan that says “we’ll break even” loses money — you will have unexpected expenses, and everything costs more than the quote. If you make a profit, either use it to bootstrap next year’s con or donate it to various BSD projects the way NYCBSDCon does.
  • About 3PM, everyone starts to drag. Have caffeine, cookies, and for us health-conscious sorts, fruit. (My only critique of NYCBSDCon? No afternoon snack.)

    My conference appearances for this year end in May. I don’t want to travel. But if you have a BSD event within a couple hours drive of Detroit, and it didn’t conflict with my prior commitments, I’d show up. (Or, if you ask politely, I’ll stay home. Whatever you prefer.)

    • Posted on

    Announcing DetroitBSDCon: May 14-17 2014

    Dan Langille has sold BSDCan to Oracle. From the early announcement, it’s clear that they’ll ruin the conference. I take this VERY personally, as I’ve worked with BSDCan for over a decade. Dan has made it clear that he’s taking the check and walking away without a second thought. This is unconscionable.

    If I want something done about it, I’ll have to do it myself.

    OpenBSD committer Nick Holland lives about two miles from me. We’ve had some discussions about what needs to happen to give the Western Hemisphere a truly free and unencumbered BSD conference. With Dan’s acceptance of Oracle’s offer, we’ve been forced to put these plans into action. As Nick has no real Internet presence, I’ve been elected to announce our efforts on my blog.

    Coming in May 2014: DetroitBSDCon!

    Detroit is a major transportation hub, with a well-connected airport and one of the world’s busiest border crossings. People will have no trouble getting here.

    Having a conference in Detroit gives us interesting possibilities, however. Traditional conference space is limited, and very hard to get at such late notice. Fortunately, the BSD community is very open to non-traditional conferences.

    One of the disadvantages to holding a conference in May is that the weather is just starting to get nice. Most of us have been trapped inside all winter, and now that it’s getting warm enough to be outside we all crowd into a stuffy windowless room for presentations. DetroitBSDCon will be a little different. Allow me to present: the Packard Plant.
    PCK-DSC_0149

    One square mile of abandoned industrial space, including offices, manufacturing floors, and more. It’s all the space we could possibly use. Each presentation or tutorial will get its own floor. Yes, some parts of the plant are deathtraps, but they’re fairly obvious.

    Best of all, we get no end of fresh air. The surrounding area is nice and quiet.

    There’s always a chance that the weather will not cooperate. The rental agency providing the chairs, tables, projection gear, and other assorted conference paraphernalia has agreed to throw in a bunch of propane pole heaters as part of the deal.

    I work for an ISP, so Internet isn’t a problem. The whole conference will be wireless. Nick has kindly volunteered to climb the water tower and mount the kit for the gigabit wireless uplink.

    Accommodations are actually very inexpensive. Detroit hosted the Super Bowl in 2006, and many people opened hotels just for that event. These days, you can get a room for free if you agree to a) not set it on fire, and b) cook meth only in the bathtub.

    And dining? Yes, there aren’t many restaurants near the Packard Plant, but we have something better than boring old sit-down restaurants. As the economy has essentially collapsed, the more entrepreneurial folks have opened unofficial dining establishments. You’ll see things like this by every major road.

    We’re arranging for dinner to come to you. Detroit has some of the world’s best barbeque and soul food, and it’ll all be there for you. Yes, smelling lunch and dinner cooking might be something of a distraction during the conference presentations, but let’s be real a moment: you go to the presentations to have a chance to work on your laptop in peace. Delicious aromas won’t hamper that in the slightest.

    And beer? Another nice thing about living in a collapsed city is that people will deliver beer by the truckload anywhere you want at any time. For a modest extra fee at registration, you’ll get a wristband that gets you free beer throughout the conference. (Speakers get a boozeband for showing up.)

    The dates for DetroitBSDCon are the same as those for Oracle BSDCan. Because seriously, how many BSDCan attendees are actually going to go to Oracle BSDCan?

    Programming is the hardest and most important part of a conference, and there’s not much time to get papers together. We’ve decided to steal the entire BSDCan programming slate. Because, seriously, those guys aren’t going to want to talk for Oracle.

    Speakers won’t need to change their travel arrangements, however. We’ve reserved cars on Canada’s Via Rail train system, leaving Ottawa on Tuesday, Wednesday, and Thursday nights, making the run down to Detroit. It’s Via Rail First class because, again, free booze. They’ll bring you to Windsor overnight, where you’ll hop the bus to the conference venue. We’ll put you up at some of the closest hotels, such as Hot Sheets Central, Scabies R Us, and Bedbugs Bonanza. Yes, they’re lower-end hotels, but seriously, after the University of Ottawa dorms, they’re fine. Plus, free beer.

    The after-party will take place Saturday night, on a train back to Ottawa so speakers can catch their flights out the next day.

    Now, some speakers might choose to go to Oracle BSDCan. They could. They have free will, after all, and they’re free to make their own decisions even if they’re wrong. In the event we have open spots in the program, Nick and I will fill in with various BSD-related presentations we’ve given over our many years in the BSD communities. We’ve found slides for talks like “Removing IPF from OpenBSD” and “ATAng: Supporting ATA Drives into the 21st Century,” so we’re all set to shore up weak spots in the program.

    Best of all, Nick and I promise to never sell DetroitBSDCon. To Oracle.

    See you in the ruins in May!

    Posted on

    BSDCan sold to Oracle?

    I am shocked and appalled. I’ve helped with BSDCan for many many years now, investing my limited time and energy into helping it become the best BSD conference on this side of the planet.

    And now Dan Langille has sold the whole thing. To Oracle.

    I know that “make something awesome, then sell out to a big company” is standard tech industry practice. But I never expected Langille to figure out a way to sell BSDCan. It never even occured to me that he would sell out our community. Either I have a failure of imagination, or he’s a clever bastard. Or both.

    While the BSDCan attendees are getting the Oracle lobotomy, Dan himself will be in Tahiti.

    I will not take this lying down. I’m tapping my resources and contacts this morning. With any luck, I’ll have an announcement of my own shortly.

    Posted on

    DNSSEC-verified SSL Certificates, the Standard Way

    DANE, or DNS-based Authentication of Named Entities, is a protocol for stuffing public key and or public key signatures into DNS. As standard DNS is forged easily, you can’t safely do this without DNSSEC. With DNSSEC, however, you now have an alternative way to verify public keys. Two obvious candidates for DANE data are SSH host keys and SSL certificate fingerprints. In this post I take you through using DNSSEC-secured DNS to verify web site SSL certificates via DNSSEC (sometimes called DNSSEC-stapled SSL certificates).

    In DNSSEC Mastery I predicted that someone would release a browser plug-in to support validation of DNSSEC-staples SSL certificates. This isn’t a very difficult prediction, as a few different people had already started down that road. One day browsers will support DANE automatically, but until then, we need a plug-in. I’m pleased to report that the fine folks at dnssec-validator.cz have completed their TLSA verification plugin. I’m using it without problems in Firefox, Chrome, and IE.

    DNS provides SSL certificate fingerprints with a TLSA record. (TLSA isn’t an acronym, it’s just a TLS record, type A. Presumably we’ll move on to TLSB at some point.)

    A TLSA record looks like this:

    _port._protocol.hostname TLSA ( 3 0 1 hash...)

    If you’ve worked with services like VOIP, this should look pretty familiar. For example, the TLSA record for port 443 on the host dnssec.michaelwlucas.com looks like this:

    _443._tcp.dnssec TLSA ( 3 0 1 4CB0F4E1136D86A6813EA4164F19D294005EBFC02F10CC400F1776C45A97F16C)

    Where do we get the hash? Run openssl(1) on your certificate file. Here I generate the SHA256 hash of my certificate file, dnssec.mwl.com.crt.

    # openssl x509 -noout -fingerprint -sha256 < dnssec.mwl.com.crt
    SHA256 Fingerprint=4C:B0:F4:E1:13:6D:86:A6:81:3E:A4:16:4F:19:D2:94:00:5E:BF:C0:2F:10:CC:40:0F:17:76:C4:5A:97:F1:6C

    Copy the fingerprint into the TLSA record. Remove the colons.

    Interestingly, you can also use TLSA records to validate CA-signed certificates. Generate the hash the same way, but change the leading string to 1 0 1. I’m using a CA-signed certificate for https://www.michaelwlucas.com, but I also validate it via DNSSEC with a record like this.

    _443._tcp.www TLSA ( 1 0 1 DBB17D0DE507BB4DE09180C6FE12BBEE20B96F2EF764D8A3E28EED45EBCCD6BA )

    So: if you go to the trouble of setting this up, what does the client see?

    Start by installing the DNSSEC/TLSA Validator plugin in your browser. (Peter Wemm has built the Firefox version of the plugin on FreeBSD, and he has a patch and a binary. Use the binary at your own risk, of course, but if you’re looking for a BSD porting project, this would be very useful.)

    The plugin adds two new status icons. One turns green if the site’s DNS uses DNSSEC, and has a small gray-with-a-touch-of-red logo if the site does not. Not having DNSSEC is not cause for alarm. The second icon turns green if the SSL certificate matches a TLSA record, gray if there is no TLSA record, and red if the certificate does not match the TLSA record.

    So: should you worry about that self-signed certificate? Check the TLSA record status. If the domain owner says “Yes, I created this cert,” it’s probably okay. If the self-signed cert fails TLSA validation, don’t go to the site.

    You can use a variety of hashes with TLSA, and you can set a variety of conditions as well. Should all certificates in your company be signed with RapidSSL certs? You can specify that in a TLSA record. Do you have a private CA? Give its fingerprint in a TLSA record. If you want to play with these things, check out my DNSSEC book.

    TLSA gives you an alternate avenue of trust, outside of the traditional and expensive CA model. Spreading TLSA more widely means that you can protect more services with SSL without additional financial expenses.