19.2.12. Network connections

This section describes how to set up a network connection, and then to configure the networking environment for use on a Linux platform. The following instructions assume that your network provides IP addresses by DHCP. If this is not the case, consult your network administrator.


NAT, IPv4 based networking provides limited IP connectivity by using user level IP services. This requires no extra privileges to set up or use but has inherent limitations. System level services, or services conflicting with those on the host can be provided using port remapping.


NAT (user mode) network support has known issues that intermittently cause networking to slow down.

One problem with using user mode networking is that, since it is acting as a NAT router between the virtual network in the model and the host network, it remaps the source port of a guest connection. This can cause problems with NFS servers. These usually default to a configuration that rejects client connections from source ports with port numbers greater than1023. With the NFS servers provided with most Linux distributions, this problem can be solved by adding the insecure option to the configuration entry for the NFS export you wish to mount.


In the /etc/exports directory is a list of local filesystem paths that are exported using NFS (NFS exports). The insecure option can be specified for any entry in /etc/exports, using:

/pub     *(ro,insecure,all_squash)
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