Differences

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--- linux_router:nftables [2023-07-09 Sun wk27 11:42] – [Hairpin NAT] baumkp
+++ linux_router:nftables [2024-09-21 Sat wk38 20:29] (current) – [iptables] baumkp
@@ Line 1: / Line 1: @@
 {{tag>linux router NFtables firewall}}
 =====NFTables Configuration=====
 The best reference for nftables is at the dedicated wiki [[https://wiki.nftables.org/|wiki nftables]]. Some other references I found [[https://gist.github.com/wolfhechel/db7ed3be31feb104752e|nftables router]]. The reference at stosb is good, but not for a router [[https://stosb.com/blog/explaining-my-configs-nftables/|Explaining My Configs: nftables]].
@@ Line 7: / Line 6: @@
 Dont forget to ensure the router is allowed to forward packets:
-  * ''sudo sysctl net.ipv6.ip_forward'' to check
+  * ''sudo sysctl net.ipv4.ip_forward'' to check
-  * ''sudo sysctl net.ipv6.ip_forward=1'' to set or =0 turn off
+  * ''sudo sysctl net.ipv4.ip_forward=1'' to set or =0 turn off
   * ''sudo sysctl net.ipv6.conf.all.forwarding=1'' similar for ipv6
+====iptables====
+It is not a good idea to have both iptables and nftables rules setup at the same time.
+  *To check existing iptables rules: ''sudo iptables -S'', the output should be as follows, indicating no restrictions:
+<code text>-P INPUT ACCEPT
+-P FORWARD ACCEPT
+-P OUTPUT ACCEPT</code>
+  *The iptables rules can be flushed with ''sudo iptables -F''.
 ====Sample NFTables configuration====
@@ Line 247: / Line 254: @@
 <tab9><color blue>       # dnat - direct allowed by port number wan incoming services to correct lan server ip.</color>\\
 <tab9>       ip daddr <color red>$wan_ip4</color> tcp dport {http, https} counter dnat to <color red>$http_server</color> ++ | \\ + <color #202000/#F0F0E0> Incoming WAN packets to the http or https ports are preroute dnat to the webserver IP address.</color>++\\
-<tab9>       ip daddr <color red>$wan_ip4</color> tcp dport {pop3s, imaps, smtp} counter dnat to <color red>$mail_server</color> ++ | \\ + <color #202000/#F0F0E0> Incoming WAN packets to the mail ports, pop3s, imaps or smtp ports are preroute dnat to the mail server IP address.</color>++\\
+<tab9>       ip daddr <color red>$wan_ip4</color> tcp dport { pop3s, imaps, imap2, smtp, submission, submissions } counter dnat to <color red>$mail_server</color> ++ | \\ + <color #202000/#F0F0E0> Incoming WAN packets to the mail ports, pop3s, imaps or smtp ports are preroute dnat to the mail server IP address.</color>++\\
 <tab9>       ip daddr <color red>$wan_ip4</color> udp dport <color red>$vpn_port</color> counter dnat to <color red>$vpn_ip4</color>  ++ | \\ + <color #202000/#F0F0E0> Incoming WAN packets to the VPN port are preroute dnat to the VPN IP address.</color>++\\
 <tab6>    }\\
@@ Line 255: / Line 262: @@
 <tab9> \\
 <tab9><color blue>      #Allow internal clients to correctly see external address "hairpin dnat"</color>   ++ | \\ + <color #202000/#F0F0E0> Hairpin nat is dicussed in greater death at [[https://wiki.kptree.net/doku.php?id=linux_router:nftables#hairpin_nat|hairpin nat]].</color>++\\
-<tab9>       ip saddr <color red>$lan_ip4</color> ip daddr <color red>$http_server</color> tcp dport {http, https} counter snat <color red>$router_ip4</color>\\
+<tab9>       ip saddr <color red>$lan_ip4</color> ip daddr <color red>$http_server</color> tcp dport { http, https } counter snat <color red>$router_ip4</color>\\
-<tab9>       ip saddr <color red>$lan_ip4</color> ip daddr <color red>$mail_server</color> tcp dport {http, https, pop3s, imaps, smtp} counter snat <color red>$router_ip4</color>\\
+<tab9>       ip saddr <color red>$lan_ip4</color> ip daddr <color red>$mail_server</color> tcp dport { http, https, pop3s, imap2, imaps, smtp, submission, submissions } counter snat <color red>$router_ip4</color>\\
 <tab9>\\
 <tab9><color blue>      #Standard postrouting nat</color>  ++ | \\ + <color #202000/#F0F0E0> The examples below show different levels of granularity in control.</color>++\\
@@ Line 272: / Line 279: @@
 ++++
+++++mail server ports:|
+  * smtp {25} / (smtps) submissions {465} / submission {587} - (My mail server uses smtp / submission on ports 25 / 587 respectivily)
+  * imap {143} / imaps {993} - (My mail server uses starttls on port 143)
+  * pop3 {110} / pop3s {995} - who still uses pop3?
+''nft'' translates ports to service namesas defined in /etc/services
+++++
 ===Some configuration notes===