Service manual

Cyclades-TS
89
Appendix A - Linux
Installation & Service Manual
I - Insert a condition in a specified location in the chain.
L - List all conditions in the chain.
F - Flush (remove) all conditions in the chain.
N - Create a new chain.
X - Deletes a user-created chain
P - Policy applied for default handling
chain is one of the following:
input - filters incoming packets
output - filters outgoing packets
forward - filters packets which are not created by the Cyclades-TS and are not destined to the Cyclades-TS
user_created_chain - a previously defined (or in the process of being defined) chain created using the N
command described above.
The output chain controls which packets are sent. A packet can be accepted by the input chain, but then rejected
by the output chain. Likewise, the forward chain controls which packets will be routed. The input chain controls
incoming packet filtering. The packet is either destined for the router or for another computer. In the latter case,
the packet is processed by the forward chain. Packets that pass through the forward chain will then be pro-
cessed by the output chain.
source and destination have the following format:
[!]
address [/ mask ] [!][ port [: port ]]
! : reverses the definition, resulting in the opposite.
address : host or network IP
port : defines a specific port
port:port : defines a range of ports
If a source or destination is not specified then 0.0.0.0/0 is used.
protocol is one of the following:
tcp, udp, icmp, all or a protocol number (see the file /etc/protocols for a list).