Improve VPN ciphers

- Remove unsupported ESP algorithm on Raspbian

extras/vpnupgrade.sh

@@ -183,6 +183,9 @@ fi
 # Update ipsec.conf for Libreswan 3.19 and newer
 IKE_NEW="  ike=3des-sha1,3des-sha2,aes-sha1,aes-sha1;modp1024,aes-sha2,aes-sha2;modp1024,aes256-sha2_512"
 PHASE2_NEW="  phase2alg=3des-sha1,3des-sha2,aes-sha1,aes-sha2,aes256-sha2_512"
+if grep -qs raspbian /etc/os-release; then
+  PHASE2_NEW="  phase2alg=3des-sha1,3des-sha2,aes-sha1,aes-sha2"
+fi
 sed -i".old-$(date +%F-%T)" \
     -e "s/^[[:space:]]\+auth=esp\$/  phase2=esp/" \
     -e "s/^[[:space:]]\+forceencaps=yes\$/  encapsulation=yes/" \

vpnsetup.sh

@@ -279,6 +279,11 @@ if grep -qs 'Raspbian GNU/Linux 9' /etc/os-release; then
   check_ip "$PRIVATE_IP" && sed -i "s/left=%defaultroute/left=$PRIVATE_IP/" /etc/ipsec.conf
 fi
 
+# Remove unsupported ESP algorithm on Raspbian
+if grep -qs raspbian /etc/os-release; then
+  sed -i '/phase2alg/s/,aes256-sha2_512//' /etc/ipsec.conf
+fi
+
 # Specify IPsec PSK
 conf_bk "/etc/ipsec.secrets"
 cat > /etc/ipsec.secrets <<EOF