If your NetBoot clients can’t start up from the server
Some clients might not start up even when NetBoot services appear to be available from the server. To find the cause, check the server’s log messages.
Check the server’s log messages
Examine the messages to identify the point where the client and server stop communicating. This can help you identify the cause of the NetBoot issue.
If you use OS X 10.11 or earlier, examine the /var/log/system.log file on the NetBoot server.
With macOS Sierra 10.12 or later, use Console app to create a filter so that you can see live messages on the NetBoot server:
In the search field, type bootpd, then press Return.
In the list that appears, choose Process. If you want to save this search, click Save.
To see live messages that the bootpd process logs on the NetBoot server, run this command:
sudo log stream --process bootpd
To see messages that have been logged in the system log datastore on the NetBoot server, run this command:
sudo log show --predicate 'senderImagePath contains "bootpd"'
Server log messages to look for in macOS Server 10.12 and later
Look for the server messages that are listed in one of the sections below, depending on whether Dynamic Host Configuration Protocol (DHCP) is enabled or disabled.
If DHCP is enabled on NetBoot Server
Look for these DHCP Discover, Offer, and Request server log messages. These examples are from a server running macOS Sierra and Server 5.2.
DHCP DISCOVER
DHCP DISCOVER [en3]: 1,40:6c:8f:37:95:27
This is a request from a client to discover DHCP servers on the network.
If you don’t see this message, something might be blocking bootp (DHCP) traffic. Make sure that any network device between the server and client, like a firewall or managed switch, is configured correctly.
OFFER
OFFER sent MacBook-Air 192.168.1.200 pktsize 300
This is a DHCP message offering a DHCP lease to a client computer.
If you use DHCP services on the NetBoot server but you don't see this message, the server might have determined that it can’t lease IP addresses for one of these reasons:
The valid subnets are out of IP addresses.
There are no valid subnets.
ACK
ACK sent MacBook-Air 192.168.1.200 pktsize 300
This message shows that the DHCP server acknowledges that the client accepts the IP address that the server offered. The DHCP server notes that the client uses the address, and the DHCP lease period begins.
DHCP INFORM
DHCP INFORM [en3]: 1,40:6c:8f:37:95:27
This message shows that the client sends a DHCP message to the server to get DHCP options.
If DHCP is disabled on NetBoot Server
If you’ve disabled DHCP, look for Boot Service Discovery Protocol (BSDP) server log messages. These are samples from a server running macOS Sierra and Server 5.2.
BSDP INFORM
BSDP INFORM [en3] 1,40:6c:8f:37:95:27 NetBoot001 arch=i386 sysid=MacBookAir5,2
This is a BSDP message from a client to generate a reply from BSDP (NetBoot) servers. The client identifies itself by its media access control (MAC) address. It lists what kind of computer it is so that the server can determine if it can start the client. BSDP uses DCHP option 43 to communicate between clients and servers.
The server logs this message when:
A client opens the Startup Disk preference pane.
A user presses and holds the Option key during startup. In this case, you usually see a BSDP ACK[LIST] message after you see this BSDP INFORM message.
A client selects a NetBoot image to start up from. In this case, you usually see a BSDP ACK[SELECT] message after you see this BSDP INFORM message.
If you don't see this message, a firewall, managed switch, or other network device between the server and client might be blocking bootp (DHCP) traffic. Check the configuration of these devices.
BSDP ACK[LIST]
NetBoot: [1,40:6c:8f:37:95:27] BSDP ACK[LIST] sent 192.168.1.200 pktsize 344
This message shows that the server replied with a list of available NetBoot images.
BSDP ACK[SELECT]
NetBoot: [1,40:6c:8f:37:95:27] BSDP ACK[SELECT] sent 192.168.1.37 pktsize 358
This message shows that the BSDP server acknowledges the client's selection of a NetBoot image.
Server log messages to look for in OS X Server 10.11 and earlier
Look for the server messages that are listed below. These examples are from a server running Mac OS X Server 10.6. Log entries from later versions of Mac OS X Server look similar.
BSDP INFORM
server bootpd[726]: BSDP INFORM [en0] 1,0:3:93:8d:e0:f4 NetBoot006 arch=ppc sysid=PowerMac4,2
This is a BSDP message from a client to generate a reply from BSDP (NetBoot) servers. The client identifies itself by its MAC address. It lists what kind of computer it is so that the server can determine if it can start the client.
The server logs this message when:
A client opens the Startup Disk preference pane.
A user presses and holds the Option key during startup. In this case, you usually see a BSDP ACK[LIST] message after you see this BSDP INFORM message.
A client selects a NetBoot image to start up from. In this case, you usually see a BSDP ACK[SELECT] message after you see this BSDP INFORM message.
BSDP ACK[LIST]
server bootpd[726]: NetBoot: [1,0:3:93:8d:e0:f4] BSDP ACK[LIST] sent 192.168.1.12 pktsize 416
This message shows that the server sends a list of available NetBoot images.
BSDP ACK[SELECT]
server bootpd[726]: NetBoot: [1,0:3:93:8d:e0:f4] BSDP ACK[SELECT] sent 192.168.1.12 pktsize 450
This message shows that the BSDP server acknowledges the client's selection of a NetBoot image.
DHCP INFORM
server bootpd[726]: DHCP INFORM [en0]: 1,0:3:93:8d:e0:f4
This message shows that the client sends a DHCP message to the server to get DHCP options.
BSDP DISCOVER
server bootpd[726]: BSDP DISCOVER [en0] 1,0:3:93:8d:e0:f4 NetBoot006 arch=ppc sysid=PowerMac4,2
This message shows that the client sends a BSDP message to try to NetBoot. The client identifies itself by its MAC address. It lists what kind of computer it is so that the server can determine if it can start the client.
If this BSDP message is not in the log, check network connectivity. The server might not be able to communicate with the client.
BDSP OFFER
server bootpd[726]: BSDP OFFER sent [1,0:3:93:8d:e0:f4] pktsize 447
This message shows that the server:
Received the DISCOVER request.
Determined that it can start the client.
Sent a message to the client that offers NetBoot.
If you don't see this entry in the log, the server determined that it couldn't start the computer. This might happen if:
The server has filtering enabled. In Server app, check the Filters tab.
The image has filtering enabled. In Server app, click the Images tab, then double-click the image.
The client can’t find a valid NetBoot or NetInstall image on the server.
DHCP DISCOVER
server bootpd[726]: DHCP DISCOVER [en0]: 1,0:3:93:8d:e0:f4
This message shows that the client requests an IP address. This request isn’t server specific. It shows only that the message is sent on the network segment. The request isn’t addressed specifically to this server. This message appears only when the DHCP service is enabled on the NetBoot server.
If you use DHCP services on the NetBoot server but don't see this message, a firewall, managed switch, or other network device between the server and client might be blocking bootp (DHCP) traffic. Check the configuration of these devices.
OFFER
server bootpd[726]: OFFER sent <no hostname> 192.168.1.12 pktsize 300
This message shows that the server offers a DHCP lease to the client computer.
If you use DHCP services on the NetBoot server but don't see this message, the server might have determined that it can’t lease IP addresses for one of these reasons:
The server determines that valid subnets are out of IP addresses.
The server determines that there are no valid subnets.
DHCP REQUEST
server bootpd[726]: DHCP REQUEST [en0]: 1,0:3:93:8d:e0:f4
This is a DHCP request from a client for the IP address. This message appears only when the DHCP service is enabled on the NetBoot server.
If you use HTTP NetBoot
Check the permissions on the web directory. If storage data is on the startup disk, you can find the permissions in /Library/Server/Web/Data/Sites/Default/NetBoot. The permissions should look like this:
drwxr-xr-x 3 root wheel 102 (time stamp) /Library/Server/Web/Data/Sites/Default/NetBoot/
If you use Diskless NetBoot (AFP)
If you’ve exceeded the server's maximum number of NetBoot connections, a client won’t start up. At the server, increase the maximum number of connections and the client "aging time" value. This value affects how often the server can reuse the available connections.
You can use the Network Install and Server software to install and reproduce only:
Non-copyrighted materials
Materials for which you own the copyright
Materials that you are authorized or legally permitted to reproduce
Network Install and Server software license agreements require that you:
Make sure that each end user is aware of software license terms for all software that the image files contain.
Make sure that all end users comply with these software license terms.
