diff --git a/src/fromager/run_network_isolation.sh b/src/fromager/run_network_isolation.sh
index 42e082f4..c3e3d40b 100755
--- a/src/fromager/run_network_isolation.sh
+++ b/src/fromager/run_network_isolation.sh
@@ -1,4 +1,4 @@
-#!/usr/bin/env -S unshare -rn /bin/bash
+#!/usr/bin/env -S unshare --uts --net --map-root-user /bin/bash
 #
 # Run command with network isolation (CLONE_NEWNET) and set up loopback
 # interface in the new network namespace. This is somewhat similar to
@@ -6,6 +6,9 @@
 # unprivilged container. The user is root inside the new namespace and mapped
 # to the euid/egid if the parent namespace.
 #
+# Unshare UTS namespace, so we can set the hostname to "localhost", so
+# lookup of "localhost" does not fail.
+#
 # Ubuntu 24.04: needs `sysctl kernel.apparmor_restrict_unprivileged_userns=0`
 # to address `unshare: write failed /proc/self/uid_map: Operation not permitted`.
 #
@@ -21,5 +24,10 @@ fi
 # bring loopback up
 ip link set lo up
 
+# set hostname to "localhost"
+if command -v hostname 2>&1 >/dev/null; then
+   hostname localhost
+fi
+
 # replace with command
 exec "$@"