CentOS/AlmaLinux Error: Failed to download metadata for repo 'appstream'

# Install migration tool
curl -O https://raw.githubusercontent.com/AlmaLinux/almalinux-deploy/master/almalinux-deploy.sh
chmod +x almalinux-deploy.sh
sudo bash almalinux-deploy.sh

# Restart
sudo reboot

# Verify
cat /etc/almalinux-release

# Replace mirrors with CentOS vaults
sudo sed -i 's|mirrorlist=|#mirrorlist=|g' /etc/yum.repos.d/CentOS-*
sudo sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-*

# Update
sudo dnf update -y

# Redirect to vaults
sudo sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-*
sudo sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-*

# Test
sudo yum update -y

# Clean yum/dnf cache
sudo dnf clean all
sudo dnf makecache

# Force a specific mirror
sudo dnf update --setopt=fastestmirror=True -y

# Check which repos are enabled
sudo dnf repolist

# Temporarily disable appstream
sudo dnf update --disablerepo=appstream -y

# Or modify the repo file
sudo nano /etc/yum.repos.d/almalinux-appstream.repo
# Change enabled=1 to enabled=0

# CentOS 7
sudo yum install iptables-services -y
sudo systemctl start iptables
sudo systemctl enable iptables

# AlmaLinux 8/9 (uses nftables by default, but you can install iptables)
sudo dnf install iptables-services -y
sudo systemctl disable firewalld
sudo systemctl stop firewalld
sudo systemctl start iptables
sudo systemctl enable iptables

# Verify
sudo iptables -L -n

# Save current config
sudo service iptables save

# Configuration file
cat /etc/sysconfig/iptables

# Reload rules
sudo systemctl restart iptables