16 November 2017

Wifi: Channel

- wifi umpama hub. satu client hantar signal/gelombang, semua boleh nampak.
- 2 hantar serentak, akan ada gangguan/interference
- CCA(Clear Channel Assessment): semak dulu tiada client lain yg hantar signal, baru hantar. kalau ada, tunggu pada masa yg rawak, baru cuba hantar semula.
- receiver mesti ACK setiap terima signal.




ref:
1- https://commotionwireless.net/docs/cck/networking/learn-wireless-basics/ (good)
2- https://documentation.meraki.com/MR/WiFi_Basics_and_Best_Practices/Channel_Planning_Best_Practices
3- 

25 October 2017

windows reactivation slmgr

slmgr -rearm

HKEY_LOCAL_MACHINE/SOFTWARE/Microsoft/Windows NT/CurrentVersion/SoftwareProtectionPlatform
–>“SkipRearm”=dword:00000000
Just change 00000000 to 00000001. (After 3 Rearms Windows 7 Reaarm key would change to 00000000,So we have to change the value to enable Rearm once again).

11 October 2017

mata api

mandian: 46% incedent , tiada malware di install.

100% attack, curi credential


Attack lifecylce:
-Initial Recon
-Initial Compromise(laptop, end user device)
-Establish Foothold
-Escalate Privileges
-Internal Recon
-Complete Mission(data theft) (disini baru ada bussiness impact.)

Prevention:
-Malware problem
-Endpoint EPP
-Tactical Intellgigence
-MSSP

Detection Breach
-First Atack, usually malware, tapi lepas breach, human attacker.
- Endpont Detection and Response(EDR)
- Operational Threat Intellignence
-MDR, Manage Detection and REsponse




Fin7
mimikatz
gizmodo
doubleagent

14 September 2017

php://input

Actually php://input allows you to read raw POST data.

php://input is not available with enctype="multipart/form-data".





So, if you simply POST a good old HTML form, the request looks something like this:
POST /page.php HTTP/1.1

key1=value1&key2=value2&key3=value3



request with a JSON-payload would look something like this:
POST /page.php HTTP/1.1

{"key1":"value1","key2":"value2","key3":"value3"}
The content would now be application/json (or at least none of the above mentioned), so PHP's $_POST-wrapper doesn't know how to handle that (yet).
The data is still there, you just can't access it through the wrapper($_POST). So you need to fetch it yourself in raw format with file_get_contents('php://input') (as long as it's not multipart/form-data-encoded).




ref:  https://stackoverflow.com/questions/8893574/php-php-input-vs-post

13 September 2017

Thunderbird baca Microsoft Exchange

EWS_URL
   https:///EWS/Exchange.asmx

vpn vs mtu

Kadang-kadang akan ada masalah dengan vpn. Contoh website boleh dibuka dari host Windows, tapi tak boleh dari ubuntu.

Salah satu penyebab adalah size MTU(Max Transfer Unit)

Secara asal, MTU utk host Windows adalah 1300, manakala ubuntu 17 pula adalah 1500.

Cara nak kecilkan saiz mtu dalam linux

# ifconfig mtu 1300




Simtom kes di atas, bila TLS Handshake  tersangkut masa Server Hello(no 'Server Finish')

11 September 2017

BitCoin ... Blockchain

Bitcoin:
https://www.youtube.com/watch?v=l9jOJk30eQs



BlockChain
https://youtu.be/_160oMzblY8

06 September 2017

Current DNS setting

Utk mengetahui komputer guna DNS server yg mana:

# nmcli device show

or

$ systemd-resolve --status

16 August 2017

disable touchpad and touchscreen on ubuntu

xinput list   <-- device="" get="" id="" p="">
xinput disable 15


https://askubuntu.com/questions/885160/cant-permanently-disable-touchpad

rabbitmq



add user
rabbitmqctl add_user newadmin s0m3p4ssw0rd
rabbitmqctl set_user_tags newadmin administrator
rabbitmqctl set_permissions -p / newadmin ".*" ".*" ".*"


list users
rabbitmqctl list_users 




list queues
rabbitmqctl list_queues 

25 July 2017

Hard Disk



- Track (https://en.wikipedia.org/wiki/Disk_sector#/media/File:Disk-structure2.svg)
- sector (fix size for each harddisk(set during formatting))
- - Geometrical sector
- - track sector
- cluster contain multiple sector
- block - unit of data(eg: berapa byk bit dd nak baca utk sekali baca/tulis )


MBR
- first sector
- contains
- - partitions info
- - bootstrap code
- VBR (~MBR, tapi di setiap partition)

11 April 2017

tor hidden server/ dark web

bacaan yg bagus
http://blog.0x3a.com/post/153468210759/monitoring-dns-inside-the-tor-network

06 April 2017

install cisco virtual atas esx

http://www.cocheno.com/2016/02/setup-cisco-xrv-on-vmware/


Langkah
1- upload vmImage ke esx
2- tambah device serial port
3- Edit Security Profile, supaya firewall(esx) allow port telnet
4- dan telnet

enable kan ssh ke cisco router

Terdapat 4 proses/langkah:
1. Device preparation (setup hostname, domain name, username, and passwords)
2. Network preparation (IP addressing & routing)
3. Generate RSA key and activate SSH
4. Apply SSH transport for the vtys


ref: http://www.mustbegeek.com/enable-ssh-in-cisco-ios-router/
[artikel yg sgt bagus, setiap command beserta keterangan yg mudah difahami ]

05 April 2017

cisco IOVs router atas vmware platform

ref: http://jamsudsanusi.net/2014/08/running-cisco-virtual-ios-iosv-via-vmware-workstation/

10 March 2017

Single vs Multi (fibre cable mode)


Kable Fibre Optik
- Cahaya lalu pada core.
- Clading akan kepung dan pastikan cahaya sampai ke hujungnya




Single Mode
- Jarak lebih jauh
- Laluan kecil, perlu sumber cahaya yg kuat, device transmisi agak mahal











Multi Mode
- jarak bawah 10 batu
- speed kurang sikit(aku pun confuse)
- harga device transmisi  kurang

11 January 2017

video codec

Ada 2 benda perlu difahami terlebih dahulu.
1- codec
2- video file format


Codec:
  algoritma(formula) yg digunakan utk compres(decompres) video. 

  • Jenis
    • MPEG-1
      • kebanyakkan VCD di kompress guna algoritma ni( *.dat file format)
    • MPEG-2
      • most DVD ( *.vob file format)
    • MPEG-4
    • DivX
    • XviD
    • X264

Video file format: 
   adalah bekas(container).

  • Jenis: 
    • mp4
      • contoh nama file: movie.mp4
    • avi (Audio Video Interleaved )
      • contoh nama file: movie.avi
    • wma
      • contoh nama file: movie.wma
    • mkv
      • contoh nama file: movie.mkv
    • Flash Video( flv dan swf)
      • contoh nama file: movie.flv   /  movie.swf
  • Fungsi utk bungkuskan audio, video dan codec dalam satu file
    #Satu file video mengandungi beberapa 'barang'. Antaranya adalah gambar, dan suara(audio).



Ada container yg boleh diisi dengan pelbagai jenis codec. Contoh: 
 - container : AVI
   - support codec:  MPEG-2, DivX, or XviD



Ada player/tv/dvd yg support container tertentu, namun tak ada semua codec.
Contoh, player A support container AVI, tapi hanya ada codec utk MPEG-2 dan DivX.
Player B pula support Container AVI, dan support semua codec.

Jadi bila ada satu file nama tuah.avi yg di kompress guna codec XviD, file ini hanya boleh dimainkan di player B sahaja, dan tidak di player A.

Untuk membolehkan tuah.avi dimainkan di player A, perlulah gunakan video converter(contoh AnyVideoConverter(http://avidemux.sourceforge.net/) atau avidemux(http://avidemux.sourceforge.net/)) utk create file baru yg dicompress guna codec XviD.




ref:
1- http://www.makeuseof.com/tag/all-you-need-to-know-about-video-codecs-containers-and-compression/
2- http://www.makeuseof.com/tag/an-introduction-to-codecs-converters-and-rippers/