From c97735f567f792cd87ba553fdc8e808d11f7d870 Mon Sep 17 00:00:00 2001
From: Kroese <kroese@users.noreply.github.com>
Date: Sat, 22 Apr 2023 01:40:03 +0200
Subject: [PATCH] Check kernel version

---
 run/network.sh | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/run/network.sh b/run/network.sh
index 1df4c84..63cfed2 100644
--- a/run/network.sh
+++ b/run/network.sh
@@ -112,8 +112,10 @@ configureNAT () {
   iptables -t nat -A PREROUTING -i "${VM_NET_DEV}" -p tcp  -j DNAT --to $VM_NET_IP
   iptables -t nat -A PREROUTING -i "${VM_NET_DEV}" -p udp  -j DNAT --to $VM_NET_IP
 
-  # Hack for guest VMs complaining about "bad udp checksums in 5 packets"
-  iptables -A POSTROUTING -t mangle -p udp --dport bootpc -j CHECKSUM --checksum-fill || true
+  if (( KERNEL > 4 )); then
+    # Hack for guest VMs complaining about "bad udp checksums in 5 packets"
+    iptables -A POSTROUTING -t mangle -p udp --dport bootpc -j CHECKSUM --checksum-fill || true
+  fi
 
   #Enable port forwarding flag
   [[ $(< /proc/sys/net/ipv4/ip_forward) -eq 0 ]] && sysctl -w net.ipv4.ip_forward=1