diff --git a/internal/pkg/container/container.go b/internal/pkg/container/container.go
index 51087ea..8606632 100644
--- a/internal/pkg/container/container.go
+++ b/internal/pkg/container/container.go
@@ -178,7 +178,10 @@ func (c *Container) CreateCommands() cmd.Set {
 	nets := map[string]types.PerNetworkOptions{}
 	dns := []net.IP{}
 	for i := range c.Networks {
-		if !c.Networks[i].IPv6.Bool {
+		if c.Networks[i].IPv6.Valid && !c.Networks[i].IPv6.Bool {
+			if c.Sysctl == nil {
+				c.Sysctl = make(map[string]string, 1)
+			}
 			c.Sysctl["net.ipv6.conf."+c.Networks[i].Name+".accept_ra"] = "0"
 		}
 		ips := []net.IP{}