Connecting XenServer to an iSCSI SAN using two separate LAN's

The solution wasn't related to iSCSI configuration on either side. The issue was with the separate LAN created for the iSCSI network. By default, only the first NIC in XenServer is configured. The others must be configured manually:

Network interface configurations are defined in files stored in the /etc/sysconfig/network-scripts directory. Each network interface has its own file with the name ifcfg-device_name. There is a device file for the physical card itself and another for the Linux bridge associated with this device. For example, the first network interface card is named eth0, and its associated bridge is xenbr0, so the network configuration information would be found in the files /etc/sysconfig/network-scripts/ifcfg-eth0 and /etc/sysconfig/network-scripts/ifcfg-xenbr0.

When XenServer Host is installed on a machine with multiple NICs, only the interface selected as the management NIC will be configured with an IP address. The NIC configurations for the additional interfaces will be present in /etc/sysconfig/network-scripts directory. If you wish to use other NICs, you need to add the line

      IPADDR=<ip address>
                  to the appropriate ifcfg-xenbrn file

If you add a new network interface to a XenServer Host, copy an existing pair of ifcfg-ethn and ifcfg-xenbrn files and edit them appropriately.

If a network interface is configured to get its network parameters from a DHCP server, its ifcfg files might be something like the following:

      DEVICE=eth1
      ONBOOT=yes
      TYPE=Ethernet
      HWADDR=00:15:60:95:4f:d0
      BRIDGE=xenbr1
      check_link_down() { return 1 ; }
                        DEVICE=xenbr1
      ONBOOT=yes
      TYPE=Bridge
      DELAY=0
      STP=off
      BOOTPROTO=dhcp
      check_link_down() { return 1 ; }
                  If a network interface is configured with static network parameters, it needs to have IP address, gateway, and netmask specified explicitly in its ifcfg-xenbrn file:

      DEVICE=xenbr1
      BOOTPROTO=none
      ONBOOT=yes
      TYPE=Bridge
      NETMASK=255.255.255.0
      IPADDR=10.100.2.6
      GATEWAY=10.100.2.1
      PEERDNS=yes
      DELAY=0
      STP=off
      check_link_down() { return 1 ; }
                  The ONBOOT tells the system to enable the network device when the computer is booted up. To disable an existing network interface, edit its ifcfg file to that the ONBOOT parameter is set to no:

      ONBOOT=no
                  You can also disable an existing NIC by renaming or deleting its ifcfg file.