- WLUG - wlug.mailman3.com

Bufferbloat demonstrations w/water and funnels
by Chuck Anderson 14 Oct '13

14 Oct '13

Here is a series of videos of a talk by Dave Täht where he uses water and funnels to demonstrate the concepts of bufferbloat: [1] Bufferbloat #1 - TCP 101 [2] Bufferbloat #2 - Tail drop queueing [3] Bufferbloat #3 - FIFO, RED, Blue, and Fair Queueing [4] Bufferbloat #4 - Wifi, Netalyzr, SFQ, SFQRED, and CoDel [5] Bufferbloat #5 - CoDel and Drop Head Queueing [6] Bufferbloat #6 - More on FQ_Codel [7] Bufferbloat #7 - Q&A [1] http://www.youtube.com/watch?v=KD5TwLQnq_8 [2] http://www.youtube.com/watch?v=PgFcqRMDqlk [3] http://www.youtube.com/watch?v=Y9xJbwb28Zc [4] http://www.youtube.com/watch?v=ol_BcKA9Ohg [5] http://www.youtube.com/watch?v=R8Esi0zjNdE [6] http://www.youtube.com/watch?v=bi-jumVNVGk [7] http://www.youtube.com/watch?v=JFH5fGNzBJU

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Changing your network scheduler in ubuntu 13.04...
by Tim Keller 14 Oct '13

14 Oct '13

Just so people know... this is how to change the scheduler on Ubuntu 13.04. tc qdisc replace dev eth0 root fq_codel limit 100 target 5ms interval 30ms ecn Obviously replace "eth0" with your appropriate network device... Enjoy, Tim. -- I am leery of the allegiances of any politician who refers to their constituents as "consumers".

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Reminder: WLUG Meeting Wed 10/9 7PM Jim Gettys on Internet buffer bloat
by Chuck Anderson 07 Oct '13

07 Oct '13

Hi folks, The next Worcester Linux Users' Group (WLUG) meeting will be held this Wednesday. This month we will have Jim Gettys from Bell Labs talk about Internet buffer bloat. This is the talk that has been rescheduled from April. Note that there has been a room change to a larger room right down the hall from our regular location. Wednesday, October 9, 7:00 - 9:00 PM WPI Campus Center, Hagglund Room 301 The Campus Center is building #7 on the campus map [1], and the Hagglund Room is room 301 on the Campus Center building floorplan [2]. [1] http://www.wpi.edu/about/visitors/campusmap.html [2] http://www.wpi.edu/Admin/CC/Floorplans/37678.htm "Internet buffer bloat, by Jim Gettys (Bell Labs) VOIP and teleconferencing often perform much more poorly on today's Internet than the Internet of a decade ago, despite great gains in bandwidth. Lots of fiber, cheap memory, smart hardware, variability of wireless goodput, changes in web browser behaviour, changes in TCP implementations, and a focus on benchmarking Internet performance solely by bandwidth, and engineer's natural reluctance to drop packets have conspired to encourage papering over problems by adding buffers; each of which may introduce latency when filled. The mistaken quest to never drop packets has destroyed interactivity under load, and often results in actual higher packet loss, as TCP's congestion avoidance algorithms have been defeated by these buffers. The lessons of the "RED manifesto" of 1997 have been forgotten or never learned by a new generation of engineers." Wednesday, October 9, 7:00 - 9:00 PM WPI Campus Center, Hagglund Room 301 Afterwards, we will go out for pizza. See you there, Chuck President, Worcester Linux Users' Group http://www.wlug.org/

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Announce: WLUG Meeting Wed 10/9 7PM Jim Gettys on Internet buffer bloat
by joel d 03 Oct '13

03 Oct '13

I plan to attend Wednesday's meeting also (90% likely at this point). Joel

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Announce: WLUG Meeting Wed 10/9 7PM Jim Gettys on Internet buffer bloat
by Chuck Anderson 03 Oct '13

03 Oct '13

Hi folks, The next Worcester Linux Users' Group (WLUG) meeting will be held at its regularly scheduled time: the 2nd Wednesday of the month, which is Wednesday, October 9, at 7PM. The location will be the WPI Campus Center, Mid-Centry Room 331. This month we will have Jim Gettys from Bell Labs talk about Internet buffer bloat. This is the talk that has been rescheduled from April. "Internet buffer bloat, by Jim Gettys (Bell Labs) VOIP and teleconferencing often perform much more poorly on today's Internet than the Internet of a decade ago, despite great gains in bandwidth. Lots of fiber, cheap memory, smart hardware, variability of wireless goodput, changes in web browser behaviour, changes in TCP implementations, and a focus on benchmarking Internet performance solely by bandwidth, and engineer's natural reluctance to drop packets have conspired to encourage papering over problems by adding buffers; each of which may introduce latency when filled. The mistaken quest to never drop packets has destroyed interactivity under load, and often results in actual higher packet loss, as TCP's congestion avoidance algorithms have been defeated by these buffers. The lessons of the "RED manifesto" of 1997 have been forgotten or never learned by a new generation of engineers." Wednesday, October 9, 7:00 - 9:00 PM WPI Campus Center, Mid-Centry Room 331 Afterwards, we will go out for pizza. See you there, Chuck President, Worcester Linux Users' Group http://www.wlug.org/

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Keysigning Party -- what to do AFTER
by Chuck Anderson 19 Sep '13

19 Sep '13

So you've attended a keysigning party and diligently checked people's key fingerprints & IDs. Now what should you do? Here is an overview of the process you should follow: 1. Sign: Look at the checklist you made at the Keysigning Party. For each user where you checked off that you verified their key information & ID, you need to import their key, verify the imported key's fingerprint matches the printout/notes that you verified at the party, sign their key(s), and send them back to them, preferrably signed+encrypted to their key. 2. Import: As you receive your signed key(s) from other people, import them to your keyring and then upload them to a keyserver. 3. Refresh: Periodically refresh your keyring from a keyserver so you get local copies of other people's keys with any additional signatures that were added since you last refreshed. Detailed instructions for each step: 1. Sign: Configure GPG to always ask for the certification level. Before signing keys, it is a good idea to set your GnuPG configuration to always ask you what certification level to assign to each key you sign. This indicates to others how carefully you verified the person's identity before you signed their key. If you don't do this, GnuPG will default to 0 which means you make no particular claim as to how careful you were. Edit $HOME/.gnupg/gpg.conf and add the following to the end: ask-cert-level You can also optionally change the default (in case you don't want to be asked every time): default-cert-level 2 1a. Sign: The CAFF Method. The easiest way to do this is to use CAFF (CA Fire & Forget) from the pgp-tools package on Fedora, or the signing-party package on Debian/Ubuntu. After installing the pgp-tools or signing-party package, you need to configure CAFF. In order to create your initial .caffrc, just run "caff" once. caff Then edit the .caffrc file in your home directory. The minimum settings you should set are: $CONFIG{'owner'} = 'YOUR FULL NAME'; $CONFIG{'email'} = 'YOUREMAIL@FOO'; $CONFIG{'bcc'} = 'YOUREMAIL@FOO'; $CONFIG{'keyid'} = [ qw{YOUR-KEY-ID YOUR-OTHER-KEY-ID-IF-YOU-HAVE-ANY} ]; $CONFIG{'local-user'} = [ qw{YOUR-KEY-ID YOUR-OTHER-KEY-ID-IF-YOU-HAVE-ANY} ]; $CONFIG{'also-encrypt-to'} = [ qw{YOUR-KEY-ID YOUR-OTHER-KEY-ID-IF-YOU-HAVE-ANY} ]; $CONFIG{'default-cert-level'} = '2'; # as above, but for CAFF specifically Note that the KEY-IDs CAFF wants are 8-byte ones rather than the usual 4-byte. Just use the last 16 digits of the fingerprint. You can also customize the email message body that CAFF will send out with each signed key. Then you just run CAFF like this: caff 0xKEY-ID1 0xKEY-ID2 0xKEY-ID3 ... ... etc to sign all those KEY-IDs. You can run it once for each person/key, or list every person's KEY-ID on a single run. CAFF will prompt you to sign people's keys one by one (which you should only do after you verify the fingerprint against your paper copy from the Keysigning Party), then it will email the signatures for each uid (email address) separately to that email address, signed+encrypted to that user. That proves that the user who can receive email at that email address, and who can decrypt the message, is the only user who can get the signature for that user/uid/email, and that is the only way they can get the signature for that uid/email (as long as you don't send your signed copy of their key to a keyserver or anywhere else--leave that to the recipient). 1b. Sign: The Manual Method. It is tricky to do the above manually without CAFF, but if you don't want to run CAFF or can't for some reason, you can sign the key and then export the signed key with gpg --export. Ideally, you should then encrypt that and send it to at least one of the email addresses listed in the uid(s) if not all of them. This is not as good as the CAFF method, because it only proves that at least ONE of the uids/email addresses is controlled by the user who has that key, and the person who controls that ONE email address can get your signature on ALL of the uids/email addresses. These commands should work for the manual method. First verify that the fingerprint matches your printout or notes from the Keysigning Party: gpg --fingerprint 0xRECIPIENT-KEY-ID Now sign the key: gpg --sign-key 0xRECIPIENT-KEY-ID Now export their key, signed+encrypted to both them and you. Store the result, ascii armoured, into a file: gpg --export 0xRECIPIENT-KEY-ID | gpg --encrypt --sign --armour --recipient 0xRECIPIENT-KEY-ID --recipient 0xYOUR-KEY-ID - > 0xRECIPIENT-KEY-ID-signed-key.asc You can verify that this came out right before emailing (since you signed/encrypted it ALSO to your own KEY-ID above) with the following: cat 0xRECIPIENT-KEY-ID-signed-key.asc | gpg -d | gpg --list-packets And you can import it to a test keyring to see the signatures like this: cat 0xRECIPIENT-KEY-ID-signed-key.asc | gpg --decrypt | gpg --import --keyring=testring.gpg --no-default-keyring gpg --list-sigs --fingerprint --keyring=testring.gpg --no-default-keyring Now that you've verified it is all correct, just attach the .asc file to an email and send it to the user's email address(es). 2. Import signed keys other people send you and then upload them. When you receive emails from other people with your signed key(s) (hopefully signed+encrypted in the email) you should import them as follows. If the sender used the CAFF Method, the entire email will be signed+encrypted and you can import the key like this: cat encrypted-email.asc | gpg --decrypt | gpg --import If the sender used the Manual Method, you will have a signed+encrypted attachment that you can import like so: cat 0xYOUR-KEY-ID-signed-key.asc | gpg --decrypt | gpg --import Now you should send your key back to a keyserver with the new signature(s) you just added: gpg --keyserver=subkeys.pgp.net --send-key 0xYOUR-KEY-ID 3. Refresh: Periodically refresh your keyring from a keyserver. In order to reap the benefits of the Web of Trust, you need to download other people's public keys so you can take advantage of the signatures on those keys to verify other people further out in the Web. As people upload their keys with additional signatures on them, your local copies become out of date so you need to refresh them to gain the additional signatures, any revocations, etc. To refresh a single key, just download that key from a keyserver: gpg --keyserver=subkeys.pgp.net --recv-key 0xKEY-ID To refresh your entire keyring (do this sparingly as it does place quite a load on the keyserver): gpg --keyserver=subkeys.pgp.net --refresh-keys That's it!

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Follow up from key signing
by Eric Martin 19 Sep '13

19 Sep '13

Hi WLUG and BLU, I have signed all of the keys I have access to. If you haven't received an email from me, it's because either a) I can't get your key, or b) the email with your signed key was lost. Please email me directly if you're expecting a signed key from me. A few people expressed interest in the suite of tools I'm using to make signing easier, and also some visualization tools I'm playing with. They're all based on Debian's pgp-tools which can be called keysigning-party on your distribution. Hands down, the most useful tool is CA Fire and Forget or caff. It's in most distributions, and if it's not in your distro (or you're on a Mac) it's pretty easy to build. Just checkout it out from svn://svn.debian.org/svn/pgp-tools/trunk, and do a make all && make install clean Now that you have caff installed on your machine, it's time for some tweaks. Go ahead and run caff by typing caff at the command prompt. This will setup the folders and files you need that we'll be tweaking. 1) I *highly* suggest making a symlink from ~/.gnupg/gpg.conf -> ~/.caff/gnupghome/ via ln -s ~/.gnupg/gpg.conf ~/.caff/gnupghome This will have caff use your preferences in gpg.conf and it makes it easier to configure / use the way you want to. 2) edit ~/.gnupg/gpg.conf and set your default key, default keyserver (most of them sync with each other so it's not a big deal, but I prefer pool.sks-keyservers.net since it handles subkeys very well.) Also to note, keys can prefer certain servers so don't worry if gpg is asking a few different servers where things are. Also, if you haven't already, set your preferences for algorithms, hashes, and compression. *NOTE* this only applies to making new keys. You should still set the proper preferences on your key via gpg --edit-key <KEYID>. Lastly, I like to add ask-cert-level so gpg (and therefore caff) ask me what certification level to give to each signature 3) edit your ~/.caffrc file to customize your name, email address, and email template / procedure for signing keys. Caff looks for 16 digit keyids, not 8 so punch in the last 16 of your fingerprint for you key. Also, I like to bcc myself on the emails in case a message gets bounced so I can resend it easily via Thunderbird 4) Once those are edited and saved, you're all set! Grab your trusted list, and feed caff one or more keyids to handle via caff <KEYID> <KEYID> <KEYID...> Don't forget to verify the fingerprint caff / gpg show you with your trusted list. I'm attaching my gpg.conf and .caffrc files for those of you who are interested. I should probably put this up as a wiki / blog post at some point in time to I can go back and update / clarify it. Also, check out: sig2dot (included in pgp-tools / keysigning-party) which is a visualizer for the Web of Trust http://pgp.cs.uu.nl/ for PGP trust paths Cheers!

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Ubuntu usb/bluetooth/android
by Bill Mills-Curran 15 Sep '13

15 Sep '13

I've had my shiny new HTC One for a while, and I've found that the USB-connected file mount/transfer/etc speed with my Ubuntu (Precious) is atrocious. I've tried both the nautilus (automount) interface and the mtp-mount: both are bad. I'm wondering whether a usb-bluetooth adapter (my laptop does not have bluetooth) would allow me to mount the smartphone filesystem and get decent performance. TIA, Bill

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Next WLUG Meeting: Keysigning Party 9/11/2013
by Eric Martin 12 Sep '13

12 Sep '13

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On Wednesday, September 11th 2013 I'll be running a PGP Key Signing party. PGP stands for Pretty Good Privacy and was developed by Phil Zimmerman in 1991 for secure communications. Signing keys allows you to say that you trust somebody's key, and extends the Web of Trust which helps everybody. To participate, please bring your public key's fingerprint, and at least (2) forms of ID (Government issued photo ID is the best way to go). If you don't yet have a public key, follow the directions for 'Preparing for the Party' from this [1] Key Signing Party HOWTO. Additionally, please upload your public key to our keyring for this event here [2]. I'll give a brief talk on PGP, and then we'll go through everybody's keys. What not to bring: A computer. Keys are signed at home, we just verify them at the Key Signing. [1] http://www.cryptnet.net/fdp/crypto/keysigning_party/en/keysigning_party.htm… [2] http://biglumber.com/x/web?keyring=4480 - -- Eric Martin Key Fingerprint = C74F 1EBF 2E80 7984 8CB5 064E BF17 D34C C704 B30F -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.13 (Darwin) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBCAAGBQJSIBdBAAoJEL8X00zHBLMPIP8P/AmMZiaHpVo3Mq72yOXONUbX bUUFKtK2qCFw0g8uAJ63D5hL7kDTbWXlTWsm+73jvkaofsKyTP8hNR0ulr5ni7dw X7EEQYSpK0MufQzEqUpfEoIa6I8Pjfa5qIWNOAuJDJpAwR8+0S2urGcQML0YarFG fys0HHWW69kYG8CTGZw/0ATmBdVZFiZEjXFk6R5wIB33SvXtzuPTLltoded5bpwK svtZf4Fa3QlaEBlg25AKWFpa6OOTt3eUBQU/KNGjhfIrLkhpsbuhcbAD6C6DPtzk 25P/9TWCSaRAcyT29amGG5qLrFEHklAic6UcOjIJtlN6ywcHSbVtHOcxIA4OmBLy e0HeskGlqu/qhqgZxDQMWbvMUdzIRqCa+pMzxGI40+w6tHnlTGPW1MZbZJxhfStW AC720w6U+q/b9iCiZHF634gbvIL6Da3G2G20Vhr4h6s1rOX53sfgIqmoB66A6SPC P6MUkO42oPdEQ7WE+69f7VHGyXgkEnJUaEXGYoBdILV3qyHyNJNKF/X7o0Vtf+xn rJTokOgCEyg5xRtzQFlYpdiIoR/BMHTteKsyki6px2hn4bCsNItOJNhG8IutVo/o qofPVIyJaiA5o7G7z8QNeppy4NBq0h752T0lU/gSs9ojhBzQ9kVuhR4PNL6QcZ98 +rLxS3s1fEsTmakIpo2G =lNN3 -----END PGP SIGNATURE-----

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Next WLUG meeting August 14th!?!
by Tim Keller 13 Aug '13

13 Aug '13

Hey Gang! Whose up for having a WLUG meeting, talking shop and eating some pizza?!? If someone has a topic they'd like to talk about please step forward otherwise this will just be a general discussion meeting. Chuck / Doug... When is this going to be? Later, Tim. -- I am leery of the allegiances of any politician who refers to their constituents as "consumers".

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