Script checking internet restriction with FFmpeg

Sometimes, you may face your FFmpeg not loading internet resources as planned. In my case, I found the case, FFmpeg can't load redirected internet object such as ts or m3u8. The below script will help you to check what kind of issues are happening in the system, so you can fix its root cause.

#!/bin/bash

echo "=============================================="
echo "  Checking FFmpeg URL Redirection Restrictions"
echo "=============================================="

# 1. Check iptables rules for HTTP/HTTPS blocking
echo -e "\n[+] Checking iptables rules..."
if sudo iptables -L -v -n | grep -E "REJECT|DROP" | grep -E "80|443"; then
    echo "⚠️  iptables is blocking HTTP/HTTPS traffic!"
else
    echo "✅ No HTTP/HTTPS blocks in iptables."
fi

# 2. Check firewalld rules
echo -e "\n[+] Checking firewalld rules..."
if sudo firewall-cmd --list-all | grep -E "block|reject"; then
    echo "⚠️  firewalld is blocking some traffic!"
else
    echo "✅ No blocking rules in firewalld."
fi

# 3. Check /etc/hosts for blocked domains
echo -e "\n[+] Checking /etc/hosts for blocked domains..."
if grep -E "0.0.0.0|127.0.0.1" /etc/hosts | grep -v "localhost"; then
    echo "⚠️  Some domains might be blocked in /etc/hosts!"
else
    echo "✅ No domain blocking in /etc/hosts."
fi

# 4. Check sysctl for ICMP redirects
echo -e "\n[+] Checking sysctl ICMP redirect settings..."
if sysctl -a 2>/dev/null | grep "accept_redirects" | grep "= 0"; then
    echo "⚠️  ICMP redirects are disabled!"
else
    echo "✅ ICMP redirects are enabled."
fi

# 5. Check SELinux status
echo -e "\n[+] Checking SELinux status..."
selinux_status=$(getenforce)
if [ "$selinux_status" == "Enforcing" ]; then
    echo "⚠️  SELinux is Enforcing. It might restrict FFmpeg!"
else
    echo "✅ SELinux is not enforcing."
fi

# 6. Check dnsmasq blocking
echo -e "\n[+] Checking dnsmasq for blocked domains..."
if [ -f /etc/dnsmasq.conf ]; then
    if grep "address=" /etc/dnsmasq.conf; then
        echo "⚠️  Some domains are blocked via dnsmasq!"
    else
        echo "✅ No domain blocking in dnsmasq."
    fi
else
    echo "✅ dnsmasq is not configured."
fi

# 7. Test FFmpeg URL redirection
echo -e "\n[+] Testing FFmpeg URL redirection..."
ffmpeg_output=$(ffmpeg -v debug -i "http://redirecting-site.com/video.mp4" 2>&1)
if echo "$ffmpeg_output" | grep -q "301 Moved Permanently\|302 Found"; then
    echo "✅ FFmpeg can follow redirects."
else
    echo "⚠️  FFmpeg redirection might be blocked!"
fi

echo -e "\n✅ Scan Completed!"

You should change redirecting-site.com/video.mp4 to your target URL.

The above script is tested on CentOS 7. You can save it as ffmpeg_check_internet_restrictions.sh:

sh ffmpeg_check_internet_restrictions.sh