When it comes to PXE boot, various problems can occur. Recently a customer turned to me reporting that their testing physical machine failed to PXE boot. One of the key information was that the testing machine was in a different subnet than the pxe-enabled distribution point. So, I asked them to do a test in the same subnet of the distribution point. They did and told me that there was no problem in that case. It is obvious that there is a problem with the network between the two subnets, that is the subnet where the testing client was and the one which the distribution point belonged to.
I asked them to capture a network packet file from both the distribution point and the testing client. The network trace file capture on the distribution point showed that no DHCP request ever received from the testing client, though the testing client could send DHCP request to the DHCP server and could get a valid IP address. Coupled with the fact that their distribution point and the testing client computer were not on the same subnet, I asked them to verify if IP Helper was properly configured (refer here and here). It took days before they came back to me again telling me that IP Helper has been configured.
However, a new issue arose. The testing client shows the following page.
smspxe.log from the distribution point shows the following messages –
12-15-2020 15:57:39.943 SMSPXE 2744 (0xab8) 00:D8:61:AE:24:3D, 40364D80-1925-11EA-BB2A-98251BAD1100: Device is in the database.
12-15-2020 15:57:39.943 SMSPXE 2744 (0xab8)
Operation: BootReply (2) Addr type: 1 Addr Len: 6 Hop Count: 0 ID: 3D24AE64
Sec Since Boot: 16 Client IP: 010.138.001.168 Your IP: 000.000.000.000 Server IP: 192.168.210.121 Relay Agent IP: 000.000.000.000
Addr: 00:d8:61:ae:24:3d:
BootFile: smsboot\x86\wdsnbp.com
Magic Cookie: 63538263
Options:
Type=53 Msg Type: 5=Ask
Type=54 Svr id: 192.168.210.121
Type=97 UUID: 00804d36402519ea11bb2a98251bad1100
Type=60 ClassId: PXEClient
Type=250 02010105040000002903020014040200ba062c436f6e66696775726174696f6e204d616e61676572206973206c6f6f6b696e6720666f7220706f6c6963792e0b0101
12-15-2020 15:57:56.509 SMSPXE 2744 (0xab8) 00:D8:61:AE:24:3D, 40364D80-1925-11EA-BB2A-98251BAD1100: no advertisements found
12-15-2020 15:57:56.556 SMSPXE 2744 (0xab8) 00:D8:61:AE:24:3D, 40364D80-1925-11EA-BB2A-98251BAD1100: No boot action. Aborted.
Note that the log says the device is in the database but no advertisements found and thus boot action was aborted. This is an important hint indicating that the device was not in a proper collection to which the task sequence was deployed. After they put the testing client into a collection and initiated a reboot as I had suggested, the previous issue disappeared, but the testing client computer stopped at the screen below.
Spotting the message “Press F12 for network service boot“, I asked the customer if he did press on F12 and he replied with a firm “Yes”. Okay. Investigation had to continue. Turning to smspxe.log, which, however, showed no errors at all –
12-16-2020 15:05:01.019 SMSPXE 2744 (0xab8) 04:0E:3C:30:C3:B3, 9655701B-A6F4-11EA-B39E-040E3C30C3B3: found optional advertisement S012000B
12-16-2020 15:05:01.019 SMSPXE 2744 (0xab8) Looking for bootImage S0100002
12-16-2020 15:05:01.035 SMSPXE 2744 (0xab8) Not in SSL.
12-16-2020 15:05:01.050 SMSPXE 2744 (0xab8) Not in SSL.
But “found optional advertisement” caught my eye. This message told us that the task sequence was deployed as Available and so it will prompt a message asking you to press F12 (refer here).
Looking at the network trace file captured on the testing client end, we could see DHCP requests were sent to the distribution point for wdsnbp.com and pxeboot.com files. All looked quite good. However, no more DHCP requests! Noting seemed wrong here. I scratched my head, not knowing what actually happened.
Then, I called the customer again asking him how he pressed F12 and he told me that he pressed F12 only once at the sight of the “Press F12 for network service boot” message on the screen. Only once! That was not enough… That only-once press on F12 would only bring the client into pxe boot but would not kick off the optional advertisement. With that thought, I asked him to keep on pressing down and up on F12. As I had expected, the issue was gone and pxe boot succeeded in the end.
SCCM Monde 