Cyclades PC400 installation manual Packet Filtering using ipchains

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Cyclades-PC400

Installation Manual

Packet Filtering using ipchains

The Linux utility ipchains can be used to filter IP packets entering, leaving and passing through interfaces. An ipchains tutorial is beyond the scope of this manual. For more information on ipchains, see the ipchains man page (by typing man ipchains at the Linux command prompt) or the howto: http://netfilter.filewatcher.org/ipchains/ HOWTO.html.

The syntax of the ipchains command is:

ipchains -command chain [-ssource] [-ddestination] [-pprotocol] [-jtarget] [-iinterface]

where command is one of the following:

A - Add a condition or rule to the end of the chain. Note that the order in which a condition appears in a chain can modify its application and the first rule added to a chain is processed first, etc.

D - Delete a condition from the chain. The condition must match exactly with the command’s arguments to be deleted.

R- Replace a condition in the chain.

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 server and are not destined to the server

user_created_chain - a previously defined (or in the process of being defined) chain created using the N command described above.

Appendix A - Linux

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Contents Cyclades-PC400 Canadian DOC Notice Cyclades-PC400 Installation ManualFCC Warning Statement Table of Contents Appendix B Hardware Specifications Upgrades of Software and Manuals What is in the BOXStep Two Hardware InstallationStep One Step Three Step Five Step FourSoftware Installation Software Installation Make config Make menuconfig Step TWO Board and System ConfigurationStep ONE Dspprofilebegin InterfnNbegin Label Description ISDN-PRI Profile Parameters Interface Parameters USA AT&T Pc400load Last or channelnumberchannelnumberchannelnumber etcPc400util -p Step ThreeStep Four Guided Examples for the Most Common Applications Step FiveISDN-BRI LANRAS DIAL-IN Application Parameters Parameter Description Value for T1 Value for E1 Line∙∙∙ ETH0 Example 2 a LAN-to-LAN Example Using ChannelsLAN 10 Multiple LAN-TO-LAN Application Parameters ∙∙∙ General Tips TroubleshootingRoot@cyclades common# ./pc400hwtest Hardware TestGlobal Test ESC Previous Menu G Global E ErrorsPasses Pg0 Board DSP U19 U06 U20 U07ESC Previous Menu G Global E ErrorsAdministrative Utilities Appendix a Information for Users not Familiar with Linux Users and PasswordsPasswd Linux File StructureCp filename destination Basic File Manipulation CommandsVi filename Mode What is done there How to Get ThereVi Editor Routing Table Net-host Netstat -rnNetmask Ssh The Secure Shell SessionProcess Table PID TTY Stat Time CommandLoading the Configuration File Get information from the board Minute hour date month day-of-week user commandSyslog Crond Utility59 * * * * /etc/testcron.sh Dhcp Dynamic Host Configuration Protocol ClientActive root /etc/tstcron.src Packet Filtering using ipchains Interface is Accept DenyCyclades-PC400 Installation Manual RJ-48C Signal Pin RxTip RxRing TxTip TxRing Appendix B Hardware SpecificationsCyclades Philippines