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🗓️ 04102025 0030
📎 networking_connectivity

HTTP/Web Tools

Tools for testing HTTP/HTTPS endpoints and downloading files.

curl - HTTP Testing​

Commands​

curl https://example.com                  # GET request
curl -I https://example.com               # Headers only (HEAD request)
curl -v https://example.com               # Verbose (debugging)
curl -X POST https://api.example.com      # POST request
curl -H "Content-Type: application/json"  # Custom headers
curl -d '{"key":"value"}' https://api.com # Send data
curl --resolve example.com:443:1.2.3.4    # Force specific IP
curl -w "%{http_code}" https://example.com # Show status code
curl -L https://example.com               # Follow redirects
curl -k https://example.com               # Ignore SSL errors (insecure!)

Use for: Testing APIs, debugging HTTP issues, checking SSL certificates, testing endpoints.

What it does: Transfer data from/to servers, supports HTTP, HTTPS, FTP, and more.

Interpreting Output​

Basic GET Request​

$ curl https://example.com
<!doctype html>
<html>
<head>
    <title>Example Domain</title>
...
  • Shows response body (HTML, JSON, etc.)
  • Silent about errors (use -v for details)

Headers Only (-I)​

$ curl -I https://example.com
HTTP/2 200
content-type: text/html; charset=UTF-8
date: Fri, 04 Oct 2025 00:30:00 GMT
server: nginx
content-length: 1256

Key headers:

  • HTTP/2 200: Protocol version and status code
    • 200 - OK
    • 301/302 - Redirect (use -L to follow)
    • 404 - Not Found
    • 500 - Server Error
    • 403 - Forbidden
  • content-type: What kind of data (HTML, JSON, etc.)
  • server: Web server software
  • date: Server's timestamp
  • content-length: Response size in bytes

Verbose Mode (-v)​

$ curl -v https://example.com
* Trying 93.184.216.34:443...
* Connected to example.com (93.184.216.34) port 443 (#0)
* TLS 1.3 connection using TLS_AES_256_GCM_SHA384
> GET / HTTP/2
> Host: example.com
> User-Agent: curl/7.88.1
> Accept: */*
>
< HTTP/2 200
< content-type: text/html
...

Key parts:

  • * lines: Connection info (DNS, TLS handshake)
  • > lines: Request sent to server
  • < lines: Response from server
  • Useful for debugging SSL issues, DNS problems, redirects

Common curl scenarios:

Testing API endpoint:

curl -X POST https://api.example.com/users \
  -H "Content-Type: application/json" \
  -d '{"name":"John","email":"john@example.com"}'

Check if website is up:

curl -I -w "%{http_code}\n" -o /dev/null -s https://example.com
# Returns: 200 (or other status code)

Debug SSL certificate:

curl -v https://example.com 2>&1 | grep -A 5 "Server certificate"

Test with specific DNS (like networking_etc_hosts but temporary):

curl --resolve example.com:443:93.184.216.34 https://example.com

wget - Download Files​

Commands​

wget https://example.com/file.zip
wget -c https://example.com/file.zip      # Continue interrupted download
wget -r https://example.com               # Recursive download (whole site)
wget --spider https://example.com         # Check if exists (don't download)
wget -O output.zip https://example.com/file.zip  # Save with specific name
wget -q https://example.com/file.zip      # Quiet mode
wget --limit-rate=200k https://example.com/file.zip  # Limit bandwidth

Use for: Downloading files, mirroring websites, batch downloads, scripts.

What it does: Non-interactive network downloader (good for scripts, can resume downloads).

Interpreting Output​

$ wget https://example.com/file.zip
--2025-10-04 00:30:00--  https://example.com/file.zip
Resolving example.com (example.com)... 93.184.216.34
Connecting to example.com (example.com)|93.184.216.34|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 10485760 (10M) [application/zip]
Saving to: 'file.zip'

file.zip          100%[=========>]  10.00M  5.21MB/s    in 1.9s

2025-10-04 00:30:02 (5.21 MB/s) - 'file.zip' saved [10485760/10485760]

Key parts:

  • Resolving: DNS lookup (uses networking_dns_tools)
  • Connecting: Establishing connection (like networking_connectivity)
  • HTTP request sent: Waiting for response
  • 200 OK: Success (same status codes as curl)
  • Length: File size
  • Progress bar: Download progress
  • Speed: Download rate

Common wget scenarios:

Resume interrupted download:

wget -c https://example.com/large-file.iso
# Can stop and restart, picks up where it left off

Download quietly (for scripts):

wget -q https://example.com/file.zip
# No output, check exit code: 0 = success

Check if file exists without downloading:

wget --spider https://example.com/file.zip
# Returns: HTTP response status

Mirror a website:

wget -r -np -k https://example.com
# -r: recursive
# -np: don't go to parent directories  
# -k: convert links for local viewing

References