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A
PPENDIX
D: C
ONNE
X
TIONS
H.323 G
ATEWAY
These descriptions focus on the firewall-protected approach, and offer
guidelines for programming a firewall that can be used to support H.323
connections that are accessible to the public internet.
Outbound Calls
Most firewalls do not restrict outbound packets or IP packets that
respond to outbound initiatives. They are configured for unrestricted
outbound packets with unrestricted reply packets. They do not have to be
changed to support outbound H.323 calls from a system.
Inbound Calls
Firewalls usually discriminate against incoming packets. The network
administrator configures a list of acceptable sources for each destination
address within a protected network. The configuration list includes a list
of entries that the firewall compares to the IP address of the local H.323
gateway and the IP address of an external caller. The configuration list
also discriminates for or against specific types of packets. IP addresses
and packet types must match for packets to pass.
The H.323 protocol uses TCP packets for call setup, and UDP packets to
carry the voice payload. Each type of packet includes an array of port
addresses that are used during the connection. Ports 1720 negotiates
which of the other available ports is used to carry the connection.
The ConneXtions gateway uses these default port assignments:
■
For UDP traffic, ConneXtions uses ports 8000-8099 by default. Calls
require four UDP ports each.
■
ConneXtions uses ports 1025-5000 for TCP traffic. You can configure
TCP ports during installation.
During ConneXtions installation, you can configure the TCP ports that are
used for incoming calls. For outgoing calls, no control is possible. Port
1720 must be preserved.
You must configure a firewall to accommodate both TCP and UDP ports
on the same system.
Gateway Load
If the gateway system NIC is attached to a LAN with heavy packet traffic
(more than 700 non-H.323 packets per second), the extra address
processing burden, which requires processing power, can slow down the
Summary of Contents for 3C10402B
Page 18: ...18 ...
Page 22: ...22 ABOUT THIS GUIDE ...
Page 26: ...26 CHAPTER 1 INTRODUCTION ...
Page 74: ...74 CHAPTER 3 FEATURE SETTINGS ...
Page 130: ...130 CHAPTER 5 TELEPHONE CONFIGURATION ...
Page 156: ...156 CHAPTER 7 CALL DISTRIBUTION GROUPS ...
Page 194: ...194 CHAPTER 8 PSTN GATEWAY CONFIGURATION ...
Page 256: ...256 CHAPTER 10 SIP MODE OPERATIONS ...
Page 328: ...328 CHAPTER 11 DIAL PLAN ...
Page 360: ...360 CHAPTER 13 DOWNLOADS ...
Page 370: ...370 CHAPTER 14 LICENSING AND UPGRADES ...
Page 406: ...406 CHAPTER 16 NETWORK MANAGEMENT ...
Page 412: ...412 CHAPTER 17 COUNTRY SETTINGS ...
Page 450: ...450 APPENDIX A INTEGRATING THIRD PARTY MESSAGING ...
Page 456: ...456 APPENDIX B ISDN COMPLETION CAUSE CODES ...
Page 510: ...510 APPENDIX F OUTBOUND CALLER ID AND 911 SERVICE ...
Page 546: ...546 APPENDIX G NBX ENTERPRISE MIB ...
Page 566: ...566 GLOSSARY ...
Page 578: ...578 INDEX ...
Page 582: ......