diff --git a/postinstall b/postinstall
index cd51411..f18af62 100755
--- a/postinstall
+++ b/postinstall
@@ -522,22 +522,36 @@ pve_conf_backup(){
 harden_ssh(){
     if [ $ssh_hardening -gt 0 ]; then
         log "Hardening ssh server"
-        rm /etc/ssh/ssh_host_*
-        log "Creating new SSH host keys"
-        ssh-keygen -t rsa -b 4096 -f /etc/ssh/ssh_host_rsa_key -N "" > /dev/null 2>&1
-        ssh-keygen -t ed25519 -f /etc/ssh/ssh_host_ed25519_key -N "" > /dev/null 2>&1
-        log "Creating new SSH moduli"
-        awk '$5 >= 3071' /etc/ssh/moduli > /etc/ssh/moduli.safe
-        mv /etc/ssh/moduli.safe /etc/ssh/moduli
 
-        log "Writing hardened SSH config"
-        if [[ $VERSION_CODENAME == "bookworm" ]]; then
-            echo -e "\n# Restrict key exchange, cipher, and MAC algorithms, as per sshaudit.com\n# hardening guide.\nKexAlgorithms sntrup761x25519-sha512@openssh.com,curve25519-sha256,curve25519-sha256@libssh.org,gss-curve25519-sha256-,diffie-hellman-group16-sha512,gss-group16-sha512-,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha256\nCiphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr\nMACs hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,umac-128-etm@openssh.com\nHostKeyAlgorithms ssh-ed25519,ssh-ed25519-cert-v01@openssh.com,sk-ssh-ed25519@openssh.com,sk-ssh-ed25519-cert-v01@openssh.com,rsa-sha2-512,rsa-sha2-512-cert-v01@openssh.com,rsa-sha2-256,rsa-sha2-256-cert-v01@openssh.com" > /etc/ssh/sshd_config.d/ssh-audit_hardening.conf
-        elif [[ $VERSION_CODENAME == "bullseye" ]]; then
-            sed -i 's/^\#HostKey \/etc\/ssh\/ssh_host_\(rsa\|ed25519\)_key$/HostKey \/etc\/ssh\/ssh_host_\1_key/g' /etc/ssh/sshd_config
-            echo -e echo -e "\n# Restrict key exchange, cipher, and MAC algorithms, as per sshaudit.com\n# hardening guide.\nKexAlgorithms curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha256\nCiphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr\nMACs hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,umac-128-etm@openssh.com\nHostKeyAlgorithms ssh-ed25519,ssh-ed25519-cert-v01@openssh.com,sk-ssh-ed25519@openssh.com,sk-ssh-ed25519-cert-v01@openssh.com,rsa-sha2-256,rsa-sha2-512,rsa-sha2-256-cert-v01@openssh.com,rsa-sha2-512-cert-v01@openssh.com" > /etc/ssh/sshd_config.d/ssh-audit_hardening.conf
+        log "Creating backup of current SSH config"
+        cp /etc/ssh/sshd_config /etc/ssh/sshd_config.bak.$(date +%F-%H%M%S)
+
+        rm -f /etc/ssh/ssh_host_*
+        ssh-keygen -t rsa -b 4096 -f /etc/ssh/ssh_host_rsa_key -N "" > /dev/null
+        ssh-keygen -t ed25519 -f /etc/ssh/ssh_host_ed25519_key -N "" > /dev/null
+
+        if [ $(awk '$5 >= 3071' /etc/ssh/moduli | wc -l) -gt 0 ]; then
+            awk '$5 >= 3071' /etc/ssh/moduli > /etc/ssh/moduli.safe
+            mv /etc/ssh/moduli.safe /etc/ssh/moduli
+        fi
+
+        INCLUDE_LINE="Include /etc/ssh/sshd_config.d/*.conf"
+        grep -qxF "$INCLUDE_LINE" /etc/ssh/sshd_config || echo "$INCLUDE_LINE" >> /etc/ssh/sshd_config
+
+        cat << EOF > /etc/ssh/sshd_config.d/ssh-audit_hardening.conf
+# Hardening profile by bashclub.org
+KexAlgorithms curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256
+Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com
+MACs hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com
+HostKeyAlgorithms ssh-ed25519,rsa-sha2-512
+EOF
+
+        if sshd -t; then
+            systemctl restart ssh.service
+        else
+            echo "Fehlerhafte SSH-Konfiguration erkannt. Bitte prüfen: /etc/ssh/sshd_config.d/ssh-audit_hardening.conf"
+            exit 1
         fi
-        systemctl restart ssh.service
     fi
 }