Please help me , am getting this issue.. 

DHCP Option and IP helper configured

At SMSPXE.log

Client boot action reply: <ClientIDReply><Identification Unknown="0" ItemKey="16795153" ServerName=""><Machine><ClientID>GUID:48101649-157B-41F6-92B4-9859E016C87C</ClientID><NetbiosName/></Machine></Identification><PXEBootAction LastPXEAdvertisementID="" LastPXEAdvertisementTime="" OfferID="000201E8" OfferIDTime="11/26/2014 3:15:00 PM" PkgID="00000078" PackageVersion="" PackagePath="http://servername/SMS_DP_SMSPKG$/00000053" BootImageID="00000053" Mandatory="0"/></ClientIDReply>
SMSPXE 8/26/2015 3:18:36 PM 4696 (0x1258)
98:90:96:D4:80:8C, 4C4C4544-004D-4C10-8050-B5C04F583532: found optional advertisement 000201E8 SMSPXE 8/26/2015 3:18:36 PM 4696 (0x1258)
Looking for bootImage 00000053 SMSPXE 8/26/2015 3:18:36 PM 4696 (0x1258)
Looking for bootImage 00000053 SMSPXE 8/26/2015 3:18:54 PM 4696 (0x1258)
Begin validation of Certificate [Thumbprint 7DE27DE9309128E2808591CF4CCC743776B8A099] issued to 'd38f2237-4763-4191-b658-f1b9bb98d357' SMSPXE 8/26/2015 3:44:25 PM 2760 (0x0AC8)
Completed validation of Certificate [Thumbprint 7DE27DE9309128E2808591CF4CCC743776B8A099] issued to 'd38f2237-4763-4191-b658-f1b9bb98d357' SMSPXE 8/26/2015 3:44:25 PM 2760 (0x0AC8)

Are your boot images distributed to the PXE enabled distribution point? Make sure you have an x86 and an x64 boot image on the DP.

Jeff

boot images already targetted to DP successfully.

what could be reason for this issue?

It appears that you may not be pressing F12 again when prompted?  You get about 2-3 seconds to press F12 after selecting the network card as the boot device.

DHCP Option and IP helper configured

Just use IPhelpers (as mentioned in the other thread).

Hi,

How have you deployed a task sequence? Are you using Unknown Comp

It appears that you may not be pressing F12 again when prompted?  You get about 2-3 seconds to press F12 after selecting the network card as the boot device.

• Proposed as answer by Jason SandysMVP 11 hours 12 minutes ago

Thanks All for your valuable response!!!

@Torsten and all , Please please help on this part.

DP+PXe is  sitting  on  Server VLAN ( subnet1)

Workstation+DHCP on Switch  is sitting on  Workstation VLAN(Subnet2)

We verfied that DHCP Option alone  didn't work for PXE booting

DHCP option+IPHelper  >> this way is able to do PXE Booting

Both must be required to be functional of PXE boot?

or  If IP helper is enough,  Please tell me how to configure to overcome PXE boot issue.

To which thread should we reply? This one or https://social.technet.microsoft.com/Forums/en-US/d63ee76e-78e8-414e-a589-6b9be5baa24e/tftp-open-timed-out-when-pxe-boot?forum=configmanagerosd? Please do not post the same question twice.Thanks. 

You use one or the other.  Preferably IP Helpers.  You do not need both configured..

• Proposed as answer by Jason SandysMVP 11 hours 12 minutes ago

As stated above, are you pressing F12 again when prompted?  Your screenshot looks like it's making contact with the PXE server.  You can verify this by watching the SMSPXE.log on your DP.

• Proposed as answer by Jason SandysMVP 11 hours 12 minutes ago