Sometimes when you connect to a multipath'ed iSCSI target you will have access to only some of its portals. This is common when the initiator is directly connected to the target's ethernet ports, as opposed to going though switches.
[my actual example at hand of such an infrastructure is a Dell MD3200i / MD3220i SAN with 4 directly connected servers]
When you do iSCSI discovery the initiator will get a list of all portals, even those that it is not actually connected to and can't speak to. With a dual controller, four ports per controller, you would see something like:
# iscsiadm --mode discovery --type sendtargets --portal 192.168.130.101
192.168.130.101:3260,1 iqn.1984-05.com.dell:powervault.md3200i.690b11c0123456789012345678901234
192.168.131.101:3260,1 iqn.1984-05.com.dell:powervault.md3200i.690b11c0123456789012345678901234
192.168.132.101:3260,1 iqn.1984-05.com.dell:powervault.md3200i.690b11c0123456789012345678901234
192.168.133.101:3260,1 iqn.1984-05.com.dell:powervault.md3200i.690b11c0123456789012345678901234
192.168.130.102:3260,2 iqn.1984-05.com.dell:powervault.md3200i.690b11c0123456789012345678901234
192.168.131.102:3260,2 iqn.1984-05.com.dell:powervault.md3200i.690b11c0123456789012345678901234
192.168.132.102:3260,2 iqn.1984-05.com.dell:powervault.md3200i.690b11C0123456789012345678901234
192.168.133.102:3260,2 iqn.1984-05.com.dell:powervault.md3200i.690b11c0123456789012345678901234
...but the host is physically cabled to the first (192.168.130.101) and sixth (192.168.131.102) ports, so it will never be able to speak with the other six portals.
Following typical documentation for iSCSI targets one ends up with all portals "known" by the initiator but the latter will only do the actual login on the ones of interest (two of them in the above example).
Should the "unreachable" ones be deleted from the initiator's configuration? Can they pose any problem being "known" even if not actually logged into ?