...
To see the default firewall rules trought through the CLI you can type:
| Code Block |
|---|
|
/system default -configuration print |
...
IPv4 firewall
Protect the router itself
- work with new with
new connections to decrease the load on a router; - create
address-list for IP addresses, that are allowed to access your router; - enable ICMP access (optionally);
drop everything else, log=yes might be added to log packets that hit the specific rule;
| Code Block |
|---|
|
/ip firewall filter
add action=accept chain=input comment="default configuration" connection-state=established,related
add action=accept chain=input src-address-list=allowed_to_router
add action=accept chain=input protocol=icmp
add action=drop chain=input
/ip firewall address-list
add address=192.168.88.2-192.168.88.254 list=allowed_to_router |
Protect the LAN devices
We will create address-list with the name "not_in_internet" which we will use for the firewall filter rules:
| Code Block |
|---|
|
/ip firewall address-list
add address=0.0.0.0/8 comment=RFC6890 list=not_in_internet
add address=172.16.0.0/12 comment=RFC6890 list=not_in_internet
add address=192.168.0.0/16 comment=RFC6890 list=not_in_internet
add address=10.0.0.0/8 comment=RFC6890 list=not_in_internet
add address=169.254.0.0/16 comment=RFC6890 list=not_in_internet
add address=127.0.0.0/8 comment=RFC6890 list=not_in_internet
add address=224.0.0.0/4 comment=Multicast list=not_in_internet
add address=198.18.0.0/15 comment=RFC6890 list=not_in_internet
add address=192.0.0.0/24 comment=RFC6890 list=not_in_internet
add address=192.0.2.0/24 comment=RFC6890 list=not_in_internet
add address=198.51.100.0/24 comment=RFC6890 list=not_in_internet
add address=203.0.113.0/24 comment=RFC6890 list=not_in_internet
add address=100.64.0.0/10 comment=RFC6890 list=not_in_internet
add address=240.0.0.0/4 comment=RFC6890 list=not_in_internet
add address=192.88.99.0/24 comment="6to4 relay Anycast [RFC 3068]" list=not_in_internet |
Brief firewall filter rule explanation:
- packets with connection-state=established,related established/related packets are added to FastTrack for faster data throughput, the firewall will work with new connections only;
- drop invalid connection and log them with prefix "invalid";
- drop attempts to reach not public addresses from your local network, apply address-list=not_in_internet before, bridge1 "bridge" is local network interface, log=yes attempts with prefix "!public_from_LAN";
- drop incoming packets that are not NATedNAT`ed, ether1 is public interface, log attempts with "!NAT" prefix;
- jump to ICMP chain to drop unwanted ICMP messages
- drop incoming packets from the Internet, which are not public IP addresses, ether1 is a public interface, log attempts with prefix "!public";
- drop packets from LAN that does not have LAN IP, 192.168.88.0/24 is local network used subnet;
| Code Block |
|---|
|
/ip firewall filter
add action=fasttrack-connection chain=forward comment=FastTrack connection-state=established,related
add action=accept chain=forward comment="Established, Related" connection-state=established,related
add action=drop chain=forward comment="Drop invalid" connection-state=invalid log=yes log-prefix=invalid
add action=drop chain=forward comment="Drop tries to reach not public addresses from LAN" dst-address-list=not_in_internet in-interface=bridge1bridge log=yes log-prefix=!public_from_LAN out-interface=!bridge1bridge
add action=drop chain=forward comment="Drop incoming packets that are not NATtedNAT`ted" connection-nat-state=!dstnat connection-state=new in-interface=ether1 log=yes log-prefix=!NAT
add action=jump chain=forward protocol=icmp jump-target=icmp comment="jump to ICMP filters"
add action=drop chain=forward comment="Drop incoming from internet which is not public IP" in-interface=ether1 log=yes log-prefix=!public src-address-list=not_in_internet
add action=drop chain=forward comment="Drop packets from LAN that do not have LAN IP" in-interface=bridge1bridge log=yes log-prefix=LAN_!LAN src-address=!192.168.88.0/24 |
Allow only needed ICMP codes in "icmp" chain:
| Code Block |
|---|
|
/ip firewall address-listfilter
add address chain=icmp protocol=icmp icmp-options=0.0.0.0/8 comment=RFC6890 list=not_in_internet
add address=172.16.0.0/12 comment=RFC6890 list=not_in_internet
add address=192.168.0.0/16 comment=RFC6890 list=not_in_internet
add address=10.0.0.0/8 comment=RFC6890 list=not_in_internet
add address=169.254.0.0/16 comment=RFC6890 list=not_in_internet
add address=127.0.0.0/8 comment=RFC6890 list=not_in_internet
add address=224.0.0.0/4 comment=Multicast list=not_in_internet
add address=198.18.0.0/15 comment=RFC6890 list=not_in_internet
add address=192.0.0.0/24 comment=RFC6890 list=not_in_internet
add address=192.0.2.0/24 comment=RFC6890 list=not_in_internet
add address=198.51.100.0/24 comment=RFC6890 list=not_in_internet
add address=203.0.113.0/24 comment=RFC6890 list=not_in_internet
add address=100.64.0.0/10 comment=RFC6890 list=not_in_internet
add address=240.0.0.0/4 comment=RFC6890 list=not_in_internet
add address=192.88.99.0/24 comment="6to4 relay Anycast [RFC 3068]" list=not_in_internet:0 action=accept \
comment="echo reply"
add chain=icmp protocol=icmp icmp-options=3:0 action=accept \
comment="net unreachable"
add chain=icmp protocol=icmp icmp-options=3:1 action=accept \
comment="host unreachable"
add chain=icmp protocol=icmp icmp-options=3:4 action=accept \
comment="host unreachable fragmentation required"
add chain=icmp protocol=icmp icmp-options=8:0 action=accept \
comment="allow echo request"
add chain=icmp protocol=icmp icmp-options=11:0 action=accept \
comment="allow time exceed"
add chain=icmp protocol=icmp icmp-options=12:0 action=accept \
comment="allow parameter bad"
add chain=icmp action=drop comment="deny all other types" |
IPv6 firewall
Protect the router itself
Create an address-list from which you allow access to the device:
| Code Block |
|---|
|
/ipv6 firewall address-list add address=fd12:672e:6f65:8899::/64 list=allowed |
Brief IPv6 firewall filter rule explanation:
- work with new packets, accept established/related packets;
- drop link-local addresses from Internet(public) interface/interface-list;
- accept access to a router from link-local addresses, accept multicast addresses for management purposes, accept your source address-list for router access;
- drop anything else;
| Code Block |
|---|
|
/ipv6 firewall filter
add action=accept chain=input comment="allow established and related" connection-state=established,related
add chain=input action=accept protocol=icmpv6 comment="accept ICMPv6"
add chain=input action=accept protocol=udp port=33434-33534 comment="defconf: accept UDP traceroute"
add chain=input action=accept protocol=udp dst-port=546 src-address=fe80::/1610 comment="accept DHCPv6-Client prefix delegation."
add action=drop chain=input in-interface=sit1in_interface_name log=yes log-prefix=dropLL_from_public src-address=fe80::/1610
add action=accept chain=input comment="allow allowed addresses" src-address-list=allowed
add action=drop chain=input
/ipv6 firewall address-list
add address=fe80::/16 list=allowed
add address=xxxx::/48 list=allowed
add address=ff02::/16 comment=multicast list=allowed |
| Note |
|---|
In certain setups where the DHCPv6 relay is used, the src address of the packets may not be from the link-local range. In that case, the src-address parameter of rule #4 must be removed or adjusted to accept the relay address. |
Protect the LAN devices
Enabled IPv6 puts makes your clients available for from public networks, set make sure to add proper firewall filter rules to protect your customers.
- accept established/related and work with new packets;
- drop invalid packets and put prefix for rules;
- accept ICMP packets;
- accept new connection from your clients to the Internet;
- drop everything else.
| Code Block |
|---|
|
/ipv6 firewall filter
add action=accept chain=forward comment=established,related connection-state=established,related
add action=drop chain=forward comment=invalid connection-state=invalid log=yes log-prefix=ipv6,invalid
add action=accept chain=forward comment=icmpv6 in-interface=!sit1in_interface_name protocol=icmpv6
add action=accept chain=forward comment="local network" in-interface=!sit1in_interface_name src-address-list=allowed
add action=drop chain=forward log-prefix=IPV6 |
...