Disable IPv6 in Ubuntu LTS 26

(2026-07-21)

Problem: Ubuntu is defaulting to trying ipv6 to find things and you don't have an ipv6 network to support the same.

Solution:

sudo tee -a /etc/sysctl.conf << 'EOF'
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1
EOF

sysctl -p