An oddball network is a network which fails to meet the assumptions
ipmasq
makes (please see Assumptions, Section 2.3 for more
information).
Should ipmasq
incorrectly identify interfaces or misclassify them
(with respect to being internal or external), create a file
/etc/ipmasq/rules/A01interfaces.rul
that defines the variables
EXTERNAL to contain the name of all your external interfaces (i.e.
EXTERNAL="eth0 eth0:0") and INTERNAL
containing the names of all interfaces connected to networks you wish to
masquerade. Make sure that the loopback interface (lo) appears in
neither EXTERNAL or INTERNAL.
Should ipmasq
incorrectly determine the IP address, netmask, or
peer IP address of an interface, create a file
/etc/ipmasq/rules/A01precompute.rul
that defines, for all
interfaces in EXTERNAL and INTERNAL, the IP address,
netmask, peer IP address, and broadcast address. (If you override the
.def to change one value, you must specify all values.)
The following shows how to define an interface foo0:
IPOFIF_foo0=10.1.2.3 NMOFIF_foo0=255.252.0.0 PEEROFIF_foo0=192.168.1.1
Aliased (i.e. foo0:0) and vlan (i.e. foo0.0) interfaces are mangled before being made into variable names. The colon in aliased interface names is transformed into an underscore, while the period in vlan interface names is transformed into two underscores.
Asymmetric routing occurs when the interface on which external packets enter the system is not the same interface on which packets leave the system. This happens most commonly with a load-balancing setup (i.e. traffic enters the system on ppp0 and ppp1, while it "leaves" the system over eql0).
To correctly indicate the interfaces over which packets enter and leave the
system, create a file /etc/ipmasq/rules/A01interfaces.rul
that
defines the variables EXTERNAL_OUT to contain the name of all your
outbound external interfaces (i.e.
EXTERNAL_OUT="eql0"), EXTERNAL_IN to
contain the name of all your inbound external interfaces (i.e.
EXTERNAL_IN="ppp0 ppp1") and INTERNAL
containing the names of all interfaces connected to networks you wish to
masquerade. Make sure that the loopback interface (lo) does not
appear in any of EXTERNAL_OUT, EXTERNAL_IN, or
INTERNAL.
Ipmasq User's Manual
Brian Bassettbrianb@debian.org
osamu@debian.org