Network Security and Search Engines

Study Notes

Threats:
- Unauthorized access
- Malware (viruses, worms, Trojan horses)
- Denial of Service (DoS) attacks
- Phishing and social engineering
Security measures:
- Firewalls
- Encryption (SSL/TLS, HTTPS)
- Authentication and authorization
- Intrusion Detection Systems (IDS) and Intrusion Prevention Systems (IPS)

How search engines work:
- Crawling: web crawlers/bots scan the web for new content
- Indexing: crawled data is stored in massive databases
- Retrieval: search algorithms match user queries with indexed data
- Ranking: results are ranked by relevance and popularity
Search engine types:
- Crawler-based (Google, Bing)
- Directory-based (Yahoo!, DMOZ)
- Hybrid (combines crawler-based and directory-based approaches)

Physical topology:
- Bus
- Star
- Ring
- Mesh
Logical topology:
- Broadcast (Ethernet)
- Token passing (Token Ring)
- Token bus (FDDI)

Components:
- Protocol (http, https, ftp, etc.)
- Subdomain (optional)
- Domain name
- Port number (optional)
- Path
- Query string (optional)
- Fragment (optional)
Example: <a href="http://www.example.com:8080/path/to/resource?query=string#fragment">http://www.example.com:8080/path/to/resource?query=string#fragment</a>

IP address structure:
- IPv4: 32-bit, dotted decimal notation (e.g., 192.0.2.1)
- IPv6: 128-bit, hexadecimal notation (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334)
IP address types:
- Unicast (one-to-one)
- Anycast (one-to-nearest)
- Multicast (one-to-many)
- Broadcast (one-to-all)

Ancaman:
- Akses tidak sah
- Malware (virus, worm, Trojan)
- Serangan Denial of Service (DoS)
- Phishing dan rekayasa sosial
Langkah keamanan:
- Firewall
- Enkripsi (SSL/TLS, HTTPS)
- Autentikasi dan autorisasi
- Sistem Deteksi Penyusupan (IDS) dan Sistem Pencegahan Penyusupan (IPS)

Cara kerja mesin pencari:
- Crawling: web crawler/bot memindai web untuk konten baru
- Indeksing: data yang dipindai disimpan dalam database besar
- Retrieval: algoritma pencarian mencocokkan kueri pengguna dengan data yang diindeks
- Perankingan: hasilnya diurutkan berdasarkan relevansi dan popularitas
Jenis mesin pencari:
- Berbasis crawler (Google, Bing)
- Berbasis direktori (Yahoo!, DMOZ)
- Hibrid (menggabungkan pendekatan crawler-based dan direktori-based)

Topologi fisik:
- Bus
- Star
- Ring
- Mesh
Topologi logis:
- Broadcast (Ethernet)
- Token passing (Token Ring)
- Token bus (FDDI)

Komponen:
- Protokol (http, https, ftp, dll.)
- Subdomain (opsional)
- Nama domain
- Nomor port (opsional)
- Path
- String kueri (opsional)
- Fragmen (opsional)
Contoh: <a href="http://www.example.com:8080/path/to/resource?query=string#fragment">http://www.example.com:8080/path/to/resource?query=string#fragment</a>

Struktur alamat IP:
- IPv4: 32-bit, notasi desimal berpola (contoh, 192.0.2.1)
- IPv6: 128-bit, notasi heksadesimal (contoh, 2001:0db8:85a3:0000:0000:8a2e:0370:7334)
Jenis alamat IP:
- Unicast (satu-ke-satu)
- Anycast (satu-ke-terdekat)
- Multicast (satu-ke-banyak)
- Broadcast (satu-ke-semua)