Multiple ip helper-addresses: simultaneous or round robin?

Unanswered Question
Feb 18th, 2009
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When more than one ip helper-address is configured on an interface, does the switch send out a unicast request to all IP helper addresses at the same time, or is there a round-robin or other sort of preferential treatment?


Thanks in advance -w

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Edison Ortiz Wed, 02/18/2009 - 17:18
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The answer is:


switch send out a unicast request to all IP helper addresses at the same time


HTH,


__


Edison.

a.alekseev Thu, 02/19/2009 - 14:36
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It cannot be at the same time.

First is the first, last is the last.


Some times it makes sense.

Edison Ortiz Thu, 02/19/2009 - 15:02
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R3 (F0/1) <--LAN--> (F0/1) R1


R3:

interface FastEthernet0/1

description R1

ip address 192.168.13.3 255.255.255.0

ip helper-address 192.168.34.4

ip helper-address 192.168.34.5


R1:


interface FastEthernet0/1

description R3

ip address dhcp

shutdown

duplex auto

speed auto

no clns route-cache


R1(config-if)#int f0/1

R1(config-if)#no shut


R3#

00:05:22: DHCPD: setting giaddr to 192.168.13.3.

00:05:22: DHCPD: BOOTREQUEST from 0063.6973.636f.2d63.6130.302e.3166.6338.2e30.3030.362d.4661.302f.31 forwarded to 192.168.34.4.

00:05:22: DHCPD: BOOTREQUEST from 0063.6973.636f.2d63.6130.302e.3166.6338.2e30.3030.362d.4661.302f.31 forwarded to 192.168.34.5.

00:05:23: IP-EIGRP(Default-IP-Routing-Table:1): Neighbor 0.0.0.0 not on common subnet for FastEthernet0/1

00:05:25: DHCPD: setting giaddr to 192.168.13.3.

00:05:25: DHCPD: BOOTREQUEST from 0063.6973.636f.2d63.6130.302e.3166.6338.2e30.3030.362d.4661.302f.31 forwarded to 192.168.34.4.

00:05:25: DHCPD: BOOTREQUEST from 0063.6973.636f.2d63.6130.302e.3166.6338.2e30.3030.362d.4661.302f.31 forwarded to 192.168.34.5.

00:05:27: DHCPD: setting giaddr to 192.168.13.3.

00:05:27: DHCPD: BOOTREQUEST from 0063.6973.636f.2d63.6130.302e.3166.6338.2e30.3030.362d.4661.302f.31 forwarded to 192.168.34.4.

00:05:27: DHCPD: BOOTREQUEST from 0063.6973.636f.2d63.6130.302e.3166.6338.2e30.3030.362d.4661.302f.31 forwarded to 192.168.34.5.


HTH,


__


Edison.

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