HP-UX IPFilter A.03.05.13 Administrator's Guide: HP-UX 11i v3
Table Of Contents
- HP-UX IPFilter Version A.03.05.13 Administrator's Guide
- Legal Notices
- Table of Contents
- Preface: About This Document
- 1 Installing and Configuring HP-UX IPFilter
- Overview of HP-UX IPFilter Installation
- Step 1: Checking HP-UX IPFilter Installation Prerequisites
- Step 2: Loading HP-UX IPFilter Software
- Step 3: Determining the Rules for IPFilter
- Step 4: Adding Rules to the Rules Files
- Step 5: Loading IPFilter and NAT Rules
- Step 6: Verifying the Installation and Configuration
- Kernel Tunable Parameters
- Supported and Unsupported Interfaces
- Troubleshooting HP-UX IPFilter
- 2 HP-UX IPFilter on HP-UX 11i Version 3
- 3 Rules and Keywords
- IPFilter Configuration Files
- Basic Rules Processing
- IPFilter Keywords
- pass and block: Controlling IP Traffic
- in and out: Bidirectional Filtering
- quick: Optimizing IPFilter Rules Processing
- on: Filtering by Network Interfaces
- from and to: Filtering by IP Addresses and Subnets
- log: Tracking Packets on a System
- proto: Controlling Specific Protocols
- opt and ipopts: Filtering on IP Options
- icmp-type: Filtering ICMP Traffic by Type
- port: Filtering on TCP and UDP Ports
- keep state: Protecting TCP, UDP, and ICMP Sessions
- flags: Tight Filtering Based on TCP Header Flags
- keep frags: Letting Fragmented Packets Pass
- with frags: Dropping Fragmented Packets
- with short: Dropping Short Fragments
- return-rst: Responding to Blocked TCP Packets
- return-icmp: Responding to Blocked ICMP Packets
- dup-to: Drop-Safe Logging
- NAT Keywords
- 4 Dynamic Connection Allocation
- 5 Firewall Building Concepts
- Blocking Services by Port Number
- Using Keep State
- Using Keep State with UDP
- Using Keep State with ICMP
- Logging Techniques
- Improving Performance with Rule Groups
- Localhost Filtering
- Using the to
- Creating a Complete Filter by Interface
- Combining IP Address and Network Interface Filtering
- Using Bidirectional Filtering Capabilities
- Using port and proto to Create a Secure Filter
- 6 HP-UX IPFilter Utilities
- 7 HP-UX IPFilter and FTP
- 8 HP-UX IPFilter and RPC
- 9 HP-UX IPFilter and IPSec
- 10 HP-UX IPFilter and Serviceguard
- A HP-UX IPFilter Configuration Examples
- B HP-UX IPFilter Static Linking
- C Performance Guidelines
- Index

Dynamic Connection Allocation
DCA Rule Modifications
Chapter 4 65
DCA Rule Modifications
The following sections describe how to modify DCA rules when HP-UX
IPFilter is running.
NOTE HP recommends configuring a redundant rule, such as pass in all, in
all DCA rules files. IPFilter does not process packets without a rule.
To modify an active rules file:
1. Run the following command:
ipf -f
<rules file>
2. Add new rules to the rules file.
DCA begins processing incoming packets with the new rules as you
add them.
CAUTION If a non-cumulative rule already has a connection limit entry in the
limit table, DCA matches incoming packets with the same source IP
address, destination IP address, and destination port to the old rule.
This occurs even if you enter a new rule higher up the list in the
active rules file. The new rule does not take effect until the current
connection limit entry expires.
To force a new rule to take effect immediately, follow the procedures
described in “Updating keep limit Rules” on page 66. Alternately, use
the following procedure to modify an inactive rules file and switch it
with the active rules file.
To modify an inactive rules file, then switch it with the active rules file:
1. Run the following command to add or modify rules in an inactive
rules file:
ipf -If
<rules file>