This error usually indicates that the iSCSI target IQN does not exist, or that the iSCSI initiator is not permitted to access the iSCSI target.

  * Check that the target IQN given in the iSCSI root path is correct.

  * Check that the iSCSI target is responding to the specified IQN.

  * Check the ACL for the iSCSI target.  Note that [[:appnote:iscsi_targets|some targets]] default to denying access; you may need to explicitly enable access for the [[:cfg:initiator-iqn|initiator IQN]] used by iPXE.

=== Upgrading from gPXE ===

If you have upgraded from gPXE to iPXE, and if you are not setting an explicit [[:cfg:initiator-iqn|iSCSI initiator IQN]] using DHCP option 203 (or an iPXE [[:scripting|script]]), then you should be aware that the default iSCSI initiator IQN has [[http://git.ipxe.org/ipxe.git/commit/960dee6|changed]] to

  * ''iqn.2010-04.org.ipxe:<hostname>'' if you have a hostname assigned (e.g. via DHCP), or

  * ''iqn.2010-04.org.ipxe:<uuid>'' if you do not have a hostname assigned.

For example, if your DHCP server specifies a hostname of ''winxp-diskless.example.com'', then iPXE will use the iSCSI initiator IQN ''iqn.2010-04.org.ipxe:winxp-diskless.example.com''.  If your DHCP server does not specify a hostname, then iPXE will use an initiator IQN based on your system UUID, such as ''iqn.2010-04.org.ipxe:d513a93e-a0a2-477e-9f46-b2d5c79bc2be''.

You may need to update your ACL rules to use the correct iSCSI initiator IQN used by iPXE, rather than the old gPXE IQN ''iqn.2000-09.org.etherboot:UNKNOWN''.