sgoncharenko

WDS on D-link routers (connecting Dlink router as a wireless extender to your WiFi network)

2011-01-12T11:50:00.000-08:00

Hi,

Looks like in the Internet and on different forums there is a mis-perception that if you want to make a wireless bridge or WiFi extender or WiFi client using another router - you have to either choose router which supports this literally(in the specs) and you have to be using the same routers or your will need to purchase some really expensive routers.

That's not true - I was able to connect DI-524 as a wireless extender to DI-824vup+ and LAN ports of this DI-524 can also use internet and be in the local network

How I did this?

First of all you need to know that almost all D-Link routers have hidden WDS (access point + wireless bridge) mode, you just need to add "/wds.htm" to the URL of your router (http://192.168.0.1/wds.htm for instance). Most people on the internet think that this page is fake and that these devices doesn't have WDS mode - well, as I already said that's not true and all these people probably just were not able to properly configure their devices for WDS.

Secondly let me tell you my configuration of the whole system

Internet "arrives" to DI-824vup+, this device distributes internet to other hosts in my network and provides Wireless network to WiFi clients. This device has 192.168.0.1 IP address in the local network and Wireless. Some devices and computers are connected directly to this router via Ethernet cables or via wireless network.

DI-524 works as a bridge ad access point in the same time (WDS mode). It transmits traffic from wireless and LAN devices (Di-524 has 192.168.0.254 as LAN address) via wireless network to DI-824 and to internet via this router. So I can have an isolated segment of network (isolated in terms of cables - no cables are involved) which is on the same local network and can use internet connection. To this DI-524 router are connected - media player and laptop via WiFi and they both can connect to the internet.

Now to details.

All routers should have the same IP addresses on their LAN interfaces

WiFi setting of Di 824vup+

WDS settings of DI-824vup+ (/wds.htm). In the Remote AP MAC you should but WiFi MAC address of DI-524

Wireless performance settings of DI-824vup+

DI-524 WAN settings should be dynamic IP connection with manual reconnect. So, that device won't try to reestablish internet access which it physically doesn't have.

DI-524 WDS settings (/wds.htm). In the Remote AP MAC you should but WiFi MAC address of DI-824vup+

DI-524 WiFi settings (Network ID, channel, security method and secret key should be the same as in DI-824vup+)

DI-524 WiFi performance settings (ssid broadcast should be disabled)

DI-524 DHCP settings - DHCP is disabled (DHCP should work only on "main" router)

That's it - feel free to ask questions in the comments.

Coupling Parallax Robot with iPaq – Part 2

2010-06-30T04:20:00.001-07:00

You can read Part 1 here

So, I was able to successfully create a C# application for WinMo5 which reads input from BoeBot and can send data back to the robot. On the BoeBot I uploaded a program which reads data from IR sensors, reports it back to the COM port and wait for instructions where to go to.

The program on the iPaq has a built-in web server which allows me to connect to the application via WiFi and to read data from BoeBot, there is also a text field which can be used to send instructions back to the robot. So, for instance, via WiFi I can send a message to go forward and then receive on the web page values from IR sensors. It’s like a remote control via WiFi via built into the robot webserver.

I’ll post my current source code later.

Coupling Parallax Robot with iPaq

2010-06-18T03:53:00.001-07:00

Recently I started a project of coupling parallax Boe bot robot with ipaq rx1950. Initially I thought it can’t be done since my Boe Bot only have a serial port, but then I found that rx1950 actually has a serial port and I can assemble a connector for this.

You might ask “why do I bother?” – the thing is that I always had a thought of implementing my science work in the university in the real life. It is a neural network which is being trained and programmed by a genetic algorithm. Basically this simulates how homo-sapience and other animals with abilities to collect knowledge evolved through the generations, but with computer you can speedup this process for a neural networks to a few minutes (it depends on the size of the network though).

PBasic that Parallax has in their robots and in controllers is quite modern and quite good language, but it won’t do what I need to implement for the whole thing. Plus, hardware restrictions won’t allow me to collect data for several thousands of virtual “species” (individual configurations of the neural network). That’s why I quickly realized that with BoeBot I can only create an “animal” with the “brain” (neural network), in order to train this thing I have to use external tools. I.E. I could select best fit for the brain, switch boebot on and program it to collect some performance data for the selected brain sample, then I can use collected data on a PC to optimize values. But this process will be very very time-consuming and not scalable and not flexible enough.

So, then I realized that I could use ipaq and connect it directly to the robot. Then I decided to proceed with 2 phases

- Phase I – a program on the iPaq will collect data from robot’s sensors and return back commands for actuators (motors). The program will include neural network and GA (genetic algorithm which will adjust the network).

- Pase II – a program will collect data about robot’s sensors and will train network which resides on the robot itself. So, even if ipaq is switched off, the “animal” will live, it just won’t evolve.

I thought I can use Linux on the iPaq (I already tried to port it and it worked quite well even with the wifi – send me a message if you want to know how, I know that it’s hard for the rx1950), but then I decided that it will be very unstable and again not flexible – it’s hard to compile for embedded Linux (I just never had enough time to learn how to do this). So I decided to go with WinMo5. VS2005+WinMo5SDK are very good development tools I should say, it was very easy to create ComPort application with C# and .Net Compact Framework.

Now I need to put everything together. I’ll let you know what I make.

P.S. iPaq rx1950 pinout for serial port:

http://www.gomadic.com/comipseradca.html

http://pinouts.ru/PDA/ipaq_22p_pinout.shtml

Apple AppStore is a nightmare for developers

2009-11-06T07:56:00.001-08:00

We submitted an app to the AppStore more than a week ago, usually it take 3-4 days to approve our product, we were OK with that, but when you release a hotfix (X.X.1 version) – why the hell on earth it should take more than a week?

Are you serious? For other our products we still have even older version. This is totally unacceptable, didn’t you know about a huge load that you will experience with all of these apps in the store? Looks like you have a single person per developer, who is wasting their time doing unnecessary QA tests.

I am very disappointed with you Apple! And when developers are very disappointed with platform for which they develop an application – this is something that should be taken care of.

Самый простой способ купить билет в Ryanair

2009-09-10T00:12:00.001-07:00

Недавно спланировал и съездил с женой в Голландию, Германию и отдыхал на Сардинии. По сложившейся традиции :) отдых = зарплате (никаких накопить, сэкономить, взять кредит). По–этому Тампере, по-этому Ryanair.

Подождал Жутчайшего promotion от Ryanair – все билеты мне обходились по 5 евро итого – 4 перелёта на двоих = 40 евро. Но встала проблема – оплата по visa добавляет к каждому перелёту ещё по 5 евро и стоимость перелётов удваивается – не очень-то радостно. Promotion заканчивался на следующий день – ни она из Visa Electron что была на руках не сработала :). Но “русские не здаются” :) вычитал в интернете что вродебы Промсвязьбанк выдаёт Электроны которые работают, кроме того у них появилась услуга Visa Electron Express или что-то типа того. Поехал – оказалось действительно – платишь 250 р (годовое обслуживание) и тебе за пол-часа выдают Электрон.

Могу подтвердить – хоть на этой карте нету Вашей фамилии, в инете карта работает на ура. Ryanair схавал! :)

Да здравствует победа русской смекалки над иностранным маркетингом – не на тех напали :)

P.S. Правда на след день цена на билет опустилась до 1 евро :)

P.P.S. Чёто я уже писал оказывается :) – ну теперь по русски заголовок :)

Ryanair Tickets to Europe with Visa Electron. Райанэиром в Европу – оплата Visa Electron

2009-07-14T02:06:00.001-07:00

Тут Ryanair поменял немного схему продажи билетов. Теперь в случае если у тебя не Visa Electron приходится доплачивать по 5 евро на человека на перелёт. Учитывая что я обычно сложные маршруты придумываю с несколькими перелётами – выходит в копеечку. Кроме того собирался покупать билеты по теже 5 евро, так что платить 10 как то не очень хотелось. Выход был найден.

Оказывается не все Visa Electron-ы у нас в стране одинаково полезны :). Судя по форумам Ryanair кушает старые VTB-шные и Промсвязьбанка. Промоакция по которой я собирался билеты брать заканчивалась на следующий день. Карточку выдают 3-5 дней. Но оказалось Промсвязьбанк выдаёт Visa Electron Мгновенного использования (без имени владельца на карте), я получил такую за 120 рублей в течение 30 минут ;)

Карта сработала like a charm :)

Мораль сей басни – на следующий день Ryanair сбросил часть билетов до 1евро :(, правда при этом конкретно мои дни подорожали и значительно – так что нечего особо расстраиватся

Last.fm is now a commercial service :(

2009-05-12T23:46:00.001-07:00

Sad but true. Will remove all my last.fm links and subscription.

Thank you last.fm, it was a good idea. Now I’m going to find another free internet radio.

Asterisk 1.6 + Voiceone + Exchange 2007

2009-05-06T09:43:00.001-07:00

Almost finished this configuration. For those who don’t know – Voiceone is a great gui for asterisk. I was able to install it with asterisk 1.6, although it was not intended to work with it (so I rewrote its code a little bit), you can reed more in this topic

http://voiceone.it/forum/viewtopic.php?t=973

In the last post I added a link to download my code. Also now I’m adding a link to my dialplan and some configuration (I will be updating this site, right now it doesn’t have all configs).

http://sites.google.com/site/sgoncharenko/Home/asterisk-configs

With respect to

Voiceone – it’s great – I like it – it is very intuitive and it’s very convenient to modify settings of my asterisk box. I even was able to do a provisioning of Linksys PAP2 boxes – check my code.

Asterisk 1.6 – it’s super. With respect to previous versions – it is more stable and works perfectly in real-time asterisk mode. They also fixed many bug with SIP and NAT. So right now my new asterisk server is sitting behind a NAT, we forwarded ports from one of our external IPs to this box (these a SIP UDP ports, you can google for them) using our CISCO ASA firewall. So, I was able to connect external client that was behind a router/NAT to the asterisk, in previous version it was a problem. All my SIP providers are working perfectly. Moreover they added TCP SIP support to this version which allowed me to connect it to Exchange unified messaging.

Exchange UM – this is awesome. Right now I can call to a person by calling to Exchange auto attendant and saying a name of that person. I can log into my mailbox by voice and Exchange will read emails for me, reschedule my meetings, compose voice messages and call people. I was able to use exchange as a voice messaging system of my Asterisk PBX. Hopefully it is already supports faxes the same way, although I am not sure :).

With these 2 (plus voiceone) guys, Exchange UM and Asterisk 1.6 I can do even more. Will tell you of course… :)

P.S. Probably will add more details in the future. If I’d have a time…

Seven Pounds

2009-04-03T06:30:00.001-07:00

Посмотрел тут фильм “Семь жизней” как его на русский перевели. Если знать английское название то суть фильма становится понятно немного раньше в процессе просмотра.

Очень сильный фильм. Очень. Даже сейчас не могу о нём нормально написать – очень большое впечатление оставляет. Такие истории не каждый день узнаёшь. Очень класно сделан фильм сам по себе, музыка вообще супер, пейзажи, погода, да всё – фильм продуман до мелочей. За какие-то жалкие час-полтора рассказывается история которую можно было обсуждать и рассказывать очень долго.

Игра Will Smith-а – просто гениально, после Хенкока (в котором он тоже не плох) это просто супер, читал что именно он сделал главного героя именно таким какой он есть.

Вобщем всем советую – это такой фильм который стоит посмотреть и который наверное никогда не забудется.

Converting Fedora 10 single drive installation to RAID1

2009-03-30T05:14:00.001-07:00

Look like there is no straight forward instructions regarding the topic. I used two of them

http://togami.com/~warren/guides/remoteraidcrazies/

http://m.linuxjournal.com/article/10217

I already installed mdadm package during the initial system setup, so I went directly to the step of copying partition table to the second (clean) disk (manual #2, Converting a Server to RAID1, 2nd step)

# sfdisk -d /dev/sda | sfdisk /dev/sdb
# fdisk /dev/sdb
> t
> 1
> fd
> t
> 2
> fd
> t
> 3
> fd
> w

I have 3 partitions (root, swap and synchronized with drbd), so I converted them all to raid fs type.

Then I created a raid 1 with single disks for all of my 3 partitions.

# mdadm -C /dev/md0 -n2 -l1 missing /dev/sdb1 # root
# mdadm -C /dev/md1 -n2 -l1 missing /dev/sdb2 # swap
# mdadm -C /dev/md2 -n2 -l1 missing /dev/sdb3 # drbd
# cat /proc/mdstat
# mdadm --detail --scan >> /etc/mdadm/mdadm.conf

As you can see I do everything like in the second manual. But now the most interesting part of this manipulations begins – you should boot from your newly created raid1.

I did everything like in the next step of the 2nd manual – copied the boot config and specified “root=/dev/md0” and (hd1,0) instead of (hd0,0).

Then the second manual suggests to rebuild initrd image with debian tool. But I don’t have it in fedora. So I followed instructions about creating initrd manually.

Unfortunately they didn’t help – my system couldn’t mount /dev/md0 device (“couldn’t mount /dev/root device” at the boot screen).

So, I googled and found old Russian article about doing the same sort of things, most of step in this article are outdated, but luckily there was a step that saved me

mkinitrd --with=raid1 --preload=raid1 --fstab=/mnt/md0/etc/fstab [image filename] [kernel version]

before that I mounted md0 raid drive to “/mnt/md0”, I also modified fstab on the raid disk – instead of local partitions I mounted raid ones (/dev/md0, /dev/md1).

Don’t forget also to change fstab on your original system – for some reasons grub could load partitions via their IDs after a reboot, so I couldn’t boot to any system.

Then I synchronized content from the /dev/sda1 to /dev/md0. installed grub onto both disks (see article #2) and used solution in the first article to boot into the second option once a time.

It finally did the trick – I stuck with the creation of initrd image – you have to specify new fstab, otherwise mkinitrd won’t know that your root partition is on the raid drive, thus initrd won’t mount raid at the very beginning, so grub won’t be able to load the kernel.

Once I booted from the raid drive I added the original one to the raid array and synchronized the array.

OK, so I will continue with creating of failover cluster, I need to configure drbd and heartbeat. Will let you know if I face any issues.

Наша Раша

2009-03-11T00:55:00.001-07:00

Оставил тут машину на выходные на парковке у торгового центра “Купеческий Двор”, сегодня утром приехал забрать.

Перед тем как оставлял – специально проверил – никаких знаков предупреждающих/запрещающих – нет. Сегодня утром парковка была закрыта! :(

Очень сильно было желание открутить болты у цепи которая перекрывает проезд, проехать и прикрутить их обратно (порчи имущества – нет, знаки повесить не потрудились – получайте) – жалко времени было – переезжал через паребрик, но это ещё повезло что лёд намёрз у паребрика и я спуститься смог (машинка то маленька) – в следующий раз (а он обязательно будет раз они знаков не вешают) обязательно откручу болты, заварят – откручу ещё что-нибудь, думаю у меня есть право и на порчу их имущества ибо они без права на то – перекрывают мне выезд. П…сы.

Провайдинг

2009-03-02T03:46:00.001-08:00

Столкнулся тут с обустройсвом сети одного провайдера в центре города. Оказалось достаточно интересно. За моих два визита удалось немного разгрести биллинговый сервак и настроить резервное подключение к интернету через Корбину – ну и задачка же это.

Выяснилось (ну я то корбиной ни разу не пользовался) что она даёт инет через ВПН (не новость хотя) пришлось настраивать этот ВПН.

Для начала встретил сопротивление от резервной сетевеой карты – что-то очень она сопротивлялась работать с тем процом, дровами и… корбиной. На следующий день поставил новые дрова – и о чудо – сетевуха заработала way more лучше.

Потом беда пришла негаданно – после установки pptp клиента выяснилось что в ядре не хватает поддержки mschap v2 – точнее шифрации для него, пришлось искать модули которые это фиксят – наконец pptp клиент заработал – но впниться активно отказывался.

После небольшого рисёрча выяснилось что этот роутер (ну как ему и следовало) набит файервольными правилами которые блокируют доступ по pptp. Погуглил – выяснил что надо открыть – открыл – инет заработал.

Потом блин так обидно – провёл несколько часов выясняе почему ДНС не работает – оказалось в NAT правилах для файервола я ошибся в номере подсети для внутрених серверов – из-за чего внутренний ДНС сервер не мог вйти наружу.

Ну теперь то вроде заработало.

Работа с этим провайдером оказалось интересной – поработаем, возможно удастся их сеть развить и сделать более надёжной и устойчивой – у меня ктати же давно зреет мысль об провайдинге VoIP телефонии, может и выйдет чего :)

UPDATE:

В момент написания статьи выяснилось что интернет с корбиной падает через час после работы. Погуглил – убрал буфферизацию на ppp устройстве – заработало стабильнее, кроме того добавил автоматический подъём соединения после обрыва. Однако напрягает что очень много потеряных пакетов на ppp соединении – хотя вроде на самом качестве связи это не отражается. В инете пишут что проблема есть с размерами MTU MRU, да и корбина на это в своих конфигах намекает, вобщем посмотрим – думаю удасться с этой проблемой справиться. Другой вариант – юзать l2tp – но там проблемы быдут с установкой – у меня ядро и сама операционка достаточно старая – много чего придётся доставлять и обновлять.

Asterisk + Skype

2009-03-01T23:53:00.001-08:00

Recently discovered that it is possible to create an asterisk to skype gateway. Well, I’ve implemented this by doing the following (everything was installed on the asterisk server):

Installed jdk
installed skype client on asterisk server, in it is a gui applications so I installed Xming on my desktop PC – this allowed me to configure skype without sitting in front of asterisk server. For those who doesn’t know hot to do this, here you are (don’t forget to allow connections to your Xming from external sources)-

export DISPLAY=IP_of_your_desktop_PC:0.0

skype

So, I configured Skype on the asterisk server, so that it will be started minimized. Then Skype could be launched by “skype &”
Then I installed SipToSis software http://www.mhspot.com/sts/siptosis.html
I had to recompile skype4java (but you probably do not need this option). Also I added direct paths for java applications.
Once I started SiptoSis software (don’t forget to export DISPLAY again) Skype asked me if I would like to allow access from external program – I allowed this.

Installation is done, now I configured SiptoSis and Asterisk configs:

SipToSis SkypeToSisAuth.props (substitute EXT with a valid asterisk extension):

*,sip:EXT@localhost:5060

SipToSis siptosis.cfg:

host_port=5070

username=skypeusername

passwd=skypepassword

Asterisk sip.conf:

[skype]

type = peer

context = your_asterisk_context

secret = skypepassword

username = skype

host = IP_address_of_asterisk_server

port = 5070

qualify = yes

That’s it, I need to mention that I was only interested in incoming calls from Skype to my Asterisk system, so I didn’t investigate SkypeOut and other features of SipToSis package.

And now – major this in my post – you have to link this SkypeIn line to a certain extension on your asterisk system (conference room or something), because there is no way to dial numbers or input any PINs via Skype client :)

So, the bottom line – It is cool but without interactive dialpad in Skype this thing can’t do much. I have a thought of implementing voice recognition for this line, so that users can say which extension they would like to dial, but this is going to be pretty complicated. I let you know if I make this, deal? :)

Mail servers, DNS and SPF records

2009-02-09T07:18:00.001-08:00

Today spent some time investigating issues with friend’s mail server. Well, it looks like some of our russian mailing systems began to check for SPF. We added and SPF record for his domain and everything began to work properly. Before that mail.ru, rambler.ru didn’t accept mail from his server.

While doing this I’ve found some interesting tools in the cloud

http://www.politemail.com/check-spf.aspx – a tool to check SPF record for your domain.

http://old.openspf.org/wizard.html – this is very famous resource, as far as I remember they started when SPF was just a small initiative group. This wizard can help you to create a correct SPF record for your domain.

http://www.intodns.com/ – nice tool instead of dnsreport which is now a commercial service.

We also checked his mail server in different blacklists. It looks like after we added an SPF record it did the trick.

Hello world!

2009-02-09T06:44:00.000-08:00

My old posts can be found there

http://sgonch.spaces.live.com

Most of my posts are in russian. On this blog I will try to post in english too.

BTW, below is my MS tag, in case you are too lazy to type http://sgoncharenko.blogspot.com in your browser :)

Don't know how to use this? check out Blackberry tool for that http://gettag.mobi