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--- tools:fwknop [2022/08/28 15:22] – darron
+++ tools:fwknop [2023/01/20 20:16] (current) – [Server] darron
@@ Line 4: / Line 4: @@
 Port knocking is used to alter packet filter rules on a host
-dependant upon a secret packet delivered to that host.
+dependant upon a packet encrypted with a secret key delivered to that host.
-It can be used to open a port to an SSH server from a single
+It can be used to open a normally closed port to an SSH server
-host. This opening will occur for a limited time period to
+from a single host for a limited time duration.
-allow authentication. After a fixed duration. the port is then closed
-to world as previously.
+===Server===
+==IPtables==
+<code>
+iptables -t filter -A INPUT -i eth0 -p tcp --syn --destination-port 22 -j REJECT --reject-with icmp-port-unreachable
+</code>
+==FWKNOP==
+==Install==
+<code>
+apt install fwknop-server
+</code>
+==Run==
+<code>
+/usr/sbin/fwknopd
+</code>
+==access.conf==
+<code>
+SOURCE: ANY
+OPEN_PORTS: tcp/22
+KEY: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+FW_ACCESS_TIMEOUT: 60
+</code>
+==fwknop.conf==
+<code>
+PCAP_INTF eth0;
+</code>
+===Client===
+==Install==
+<code>
+apt install fwknop-client
+</code>
+==.fwknoprc==
+<code>
+[default]
+[hostname]
+SPA_SERVER      x.x.x.x
+ACCESS          tcp/22
+ALLOW_IP        resolve
+KEY             XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+</code>
+==.ssh/config==
+<code>
+Match host hostname exec "fwknop -n hostname && sleep 0.5"
+</code>
 ===Resources===
 [[https://www.cipherdyne.org/fwknop/|Home page]]

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