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I'm seeing strange DHCP behavior between Android and Windows and wanted to see if anyone here could make sense of it. It seems like Android is spamming a dozen or so discovers in a second, and ignoring anything the server says until the lease renewal time is up (from a prior connection).

https://www.cloudshark.org/captures/e6dcb03e4e03

EDIT: There are comments attached to the capture.

asked 02 Sep '15, 09:22

lordbah's gravatar image

lordbah
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edited 03 Sep '15, 08:19


The DHCP server responses are broadcast, while the client asks for unicast responses. Therefore the responses don't seem to arrive.

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answered 04 Sep '15, 03:52

Jaap's gravatar image

Jaap ♦
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So that means Windows 7 ICS DHCP server isn't honoring the unicast flag. Well, it is only a SHOULD in the standard, right?

Sometimes Android does see the response even though it is broadcast.

There are a number of hits on setting this flag on Windows as a DHCP client. Nothing I can find about it with Windows as DHCP server. I'm interested to hear of workarounds - arcane registry settings or whatever that would cause Windows to unicast.

Windows Firewall has a setting "Allow unicast response to multicast or broadcast network traffic", but is set to Yes in all profiles so it shouldn't be causing this. (Action/Properties/Settings/Customize)

(04 Sep '15, 10:31) lordbah
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question asked: 02 Sep '15, 09:22

question was seen: 1,744 times

last updated: 04 Sep '15, 10:31

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