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28
DHCP Relay
This chapter shows you how to set up DHCP relays for each VLAN.
28.1 DHCP Relay
DHCP (Dynamic Host Configuration Protocol, RFC 2131 and RFC 2132) allows individual
clients to obtain TCP/IP configuration at start-up from a DHCP server. You can configure the
IES-1248 to relay DHCP requests to one or more DHCP servers and the server’s responses
back to the clients. You can specify default DHCP servers for all VLAN, and you can specify
DHCP servers for each VLAN.
28.2 DHCP Relay Agent Information Option (Option 82)
The IES-1248 can add information to DHCP requests that it relays to a DHCP server. This
helps provide authentication about the source of the requests. You can also specify additional
information for the IES-1248 to add to the DHCP requests that it relays to the DHCP server.
Please see RFC 3046 for more details.
28.2.1 DHCP Relay Agent Circuit ID and Remote ID Sub-option
Formats
The DHCP relay agent information feature adds an Agent Information field to the option 82
field of the DHCP headers of DHCP request frames that the IES-1248 relays to a DHCP
server. The Agent Information field that the IES-1248 adds contains an “Agent Circuit-ID sub-
option” that includes the port number, VLAN ID and optional information about the port
where the DHCP request was received.
The following figure shows the format of the Agent Circuit ID sub-option. The 1 in the first
field identifies this as an Agent Circuit ID sub-option. The length N gives the total number of
octets in the Agent Information Field. If the configuration request was received on a DSL port,
a 2-byte Port No field specifies the ingress port number (the first byte is always 0, the second
byte is in hexadecimal format). The next field is 2 bytes and displays the DHCP request
packet’s VLAN ID. The last field (A) can range from 0 to 24 bytes and is optional information
(that you specify) about this relay agent.
Figure 101
DHCP Relay Agent Circuit ID Sub-option Format
Содержание IES-1248-71
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Страница 8: ...Safety Warnings IES 1248 71 73 User s Guide 8 ...
Страница 38: ...List of Tables IES 1248 71 73 User s Guide 38 ...
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Страница 51: ...Chapter 2 Hardware Installation IES 1248 71 73 User s Guide 51 Figure 6 IES 1248 Frame Ground Frame Ground ...
Страница 52: ...Chapter 2 Hardware Installation IES 1248 71 73 User s Guide 52 ...
Страница 60: ...Chapter 3 Front Panel Connections IES 1248 71 73 User s Guide 60 ...
Страница 68: ...Chapter 4 MDF Connections IES 1248 71 73 User s Guide 68 ...
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Страница 81: ...Chapter 7 Introducing the Web Configurator IES 1248 71 73 User s Guide 81 Figure 30 Logout ...
Страница 82: ...Chapter 7 Introducing the Web Configurator IES 1248 71 73 User s Guide 82 ...
Страница 110: ...Chapter 12 User Account IES 1248 71 73 User s Guide 110 ...
Страница 116: ...Chapter 13 Switch Setup IES 1248 71 73 User s Guide 116 ...
Страница 118: ...Chapter 14 IP Setup IES 1248 71 73 User s Guide 118 ...
Страница 150: ...Chapter 17 xDSL Profiles Setup IES 1248 71 73 User s Guide 150 ...
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Страница 166: ...Chapter 19 VLAN IES 1248 71 73 User s Guide 166 ...
Страница 184: ...Chapter 22 Multicast VLAN IES 1248 71 73 User s Guide 184 ...
Страница 216: ...Chapter 30 2684 Routed Mode IES 1248 71 73 User s Guide 216 ...
Страница 222: ...Chapter 31 PPPoA to PPPoE IES 1248 71 73 User s Guide 222 ...
Страница 226: ...Chapter 32 DSCP IES 1248 71 73 User s Guide 226 ...
Страница 240: ...Chapter 36 Syslog IES 1248 71 73 User s Guide 240 ...
Страница 248: ...Chapter 37 Access Control IES 1248 71 73 User s Guide 248 ...
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Страница 259: ...Chapter 39 Alarm IES 1248 71 73 User s Guide 259 ...
Страница 260: ...Chapter 39 Alarm IES 1248 71 73 User s Guide 260 ...
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Страница 296: ...Chapter 44 Commands IES 1248 71 73 User s Guide 296 ...
Страница 304: ...Chapter 45 Command Examples IES 1248 71 73 User s Guide 304 ...
Страница 320: ...Chapter 47 DHCP Commands IES 1248 71 73 User s Guide 320 ...
Страница 328: ...Chapter 48 IEEE 802 1Q Tagged VLAN Commands IES 1248 71 73 User s Guide 328 ...
Страница 334: ...Chapter 49 MAC Commands IES 1248 71 73 User s Guide 334 ...
Страница 348: ...Chapter 50 IGMP Commands IES 1248 71 73 User s Guide 348 ...
Страница 352: ...Chapter 51 Packet Filter Commands IES 1248 71 73 User s Guide 352 ...
Страница 362: ...Chapter 53 Firmware and Configuration File Maintenance IES 1248 71 73 User s Guide 362 ...
Страница 394: ...Chapter 55 ADSL Commands IES 1248 71 73 User s Guide 394 ...
Страница 418: ...Chapter 56 Virtual Channel Management IES 1248 71 73 User s Guide 418 ...
Страница 424: ...Chapter 57 ACL Commands IES 1248 71 73 User s Guide 424 ...
Страница 436: ...Chapter 58 Troubleshooting IES 1248 71 73 User s Guide 436 ...
Страница 437: ...437 PART VI Appendices and Index Product Specifications 439 Legal Information 449 Index 457 ...
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Страница 448: ...Appendix B Removing and Installing a Fuse IES 1248 71 73 User s Guide 448 ...
Страница 452: ...Appendix C Legal Information IES 1248 71 73 User s Guide 452 ...
Страница 464: ...Index IES 1248 71 73 User s Guide 464 ...