158 lines
2.4 KiB
Markdown
158 lines
2.4 KiB
Markdown
# 9.1 Netzwerkdienste
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## Wichtige Netzwerkdienste
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### Übersicht
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```
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Netzwerkdienste
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├── DHCP (IP-Adressen)
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├── DNS (Namen auflösen)
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├── HTTP/HTTPS (Web)
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├── SMTP (E-Mail)
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├── FTP/SFTP (Dateien)
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├── SSH (Remote-Zugriff)
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└── LDAP (Verzeichnis)
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```
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---
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## DHCP (Dynamic Host Configuration Protocol)
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### Funktion
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```
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DHCP - Ablauf
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Client → DHCP Discover (Broadcast)
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Server → DHCP Offer
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Client → DHCP Request
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Server → DHCP Acknowledge
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```
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### Konfiguration
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```
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DHCP-Server - Einstellungen
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├── IP-Bereich (Pool)
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├── Subnetzmaske
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├── Gateway
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├── DNS-Server
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├── Lease Time
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└── Reservierungen
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```
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### Beispiel
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```yaml
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# DHCP-Konfiguration (ISC DHCP)
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subnet 192.168.1.0 netmask 255.255.255.0 {
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range 192.168.1.100 192.168.1.200;
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option routers 192.168.1.1;
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option domain-name-servers 8.8.8.8, 8.8.4.4;
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default-lease-time 600;
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max-lease-time 7200;
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}
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```
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---
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## DNS (Domain Name System)
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### Aufbau
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```
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DNS - Hierarchie
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. (Root)
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├── de
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│ └── example.de
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├── com
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│ └── example.com
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└── org
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└── wikipedia.org
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```
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### DNS-Records
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| Typ | Bedeutung | Beispiel |
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|-----|----------|----------|
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| A | IPv4-Adresse | example.com → 93.184.216.34 |
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| AAAA | IPv6-Adresse | example.com → ... |
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| CNAME | Alias | www → example.com |
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| MX | Mail-Server | @ → mail.example.com |
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| TXT | Text | v=spf1 include:_spf.google.com ~all |
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### nslookup/dig
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```bash
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# DNS-Abfrage
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nslookup example.com
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dig example.com
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# Bestimmter Record-Typ
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dig MX example.com
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```
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---
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## HTTP/HTTPS
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### HTTP-Request
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```
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GET /index.html HTTP/1.1
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Host: www.example.com
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User-Agent: Mozilla/5.0
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Accept: text/html
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```
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### HTTPS/TLS
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```
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HTTPS - Ablauf
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1. Client → Server: Hallo
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2. Server → Client: Zertifikat + Public Key
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3. Client: Zertifikat prüfen
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4. Client → Server: Pre-Master-Secret (verschlüsselt)
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5. Beide: Session Key generieren
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6. Verschlüsselte Kommunikation
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```
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---
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## Weitere Dienste
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### SSH (Secure Shell)
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```bash
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# Verbinden
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ssh benutzer@server.example.com
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# Datei kopieren
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scp datei.txt benutzer@server:/pfad/
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# Schlüssel generieren
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ssh-keygen -t ed25519
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```
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### SMTP (E-Mail-Versand)
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```
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SMTP - Ablauf
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1. EHLO client
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2. MAIL FROM: absender@example.com
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3. RCPT TO: empfaenger@example.com
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4. DATA
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5. Nachricht
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6. QUIT
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```
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---
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## Querverweise
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- [[LF9-02-Server|Nächstes Thema: Server]]
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---
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*Stand: 2024*
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