Server 4.1.5/OS X 10.10.5 DHCP server stopped working

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Level 1

4 points

Server 4.1.5/OS X 10.10.5 DHCP server stopped working

Hi,

After upgrading to 10.10.5 I immediately updated Server to 4.1.5. That went seemingly without error.

After the final reboot, all seemed well. The local clients even got DHCP leases. A little while later, though, clients received no answer from the DHCP server anymore.

The DHCP service is bound to the right interface (en0). The service is started. A "netstat -na | grep 67" conforms there's a listener on UDP port 67.

Client leases do arrive, as witnessed by a "sudo tcpdump -vvnni en0 port 67"; this also shows that there are no responses from the DHCP server.

The DHCP service logs show that the service starts upon system boot, and handles a few requests. After that, no requests are logged.

Upon disabling the service in Server and running it by hand in interactive/debug mode ("sudo /usr/lib/bootps -dDv") shows that the service starts, but even though tcpdump clearly shows the DHCP requests arriving, the bootps daemon shows nothing.

Reverting to 10.10.4/4.1.3 restores functionality. Upgrading to 10.10.5/4.1.5 breaks DHCP service again.

I suspect breakage. Am I missing something?

iMac, OS X Server, 10.10.5

Posted on Aug 17, 2015 1:35 AM

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Answer 1

roenass Author

Level 1

4 points

Sep 2, 2015 2:32 AM in response to roenass

No change, but still investigating. I've resorted to running ISC DHCPD instead, as a workaround for the time being.

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Answer 2

roenass Author

Level 1

4 points

Sep 16, 2015 4:18 PM in response to roenass

Found it, fixed it.

As it turns out, server has its firewall enabled, with default network access from "private networks".

... And without a service defined for DHCP. This explains why the service is running and can be seen to be listening on the "bootps" port.

I've added a "DHCP" custom access object, which is defined as applicable to inbound udp/67 traffic and which accepts connections from private networks as well as 0.0.0.0.

And presto, that restored sanity.

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