Technical data

Gateway Routing Daemon (GATED) Configuration Reference
A.12 Protocol Overview
A.12.6 Kernel Interface
Although the kernel interface is not technically a routing protocol, it has many
characteristics of one, and GATED handles it similarly. The routes GATED
chooses to install in the kernel forwarding table are those that will actually be
used by the kernel to forward packets.
The add, delete and change operations that GATED must use to update the
typical kernel forwarding table take a non-trivial amount of time. The time
used does not present a problem for older routing protocols (RIP, EGP), which
are not particularly time critical and do not easily handle very large numbers of
routes anyway. The newer routing protocols (OSPF, BGP) have stricter timing
requirements and are often used to process many more routes. The speed of the
kernel interface becomes critical when these protocols are used.
A.12.7 Static Routes
Static statements define the static routes used by GATED. A single static
statement can specify any number of routes. The static statements occur after
protocol statements and before control statements in the TCPIP$GATED.CONF
file. Any number of static statements may be specified, each containing any
number of static route definitions. These routes can be overridden by routes with
better preference values.
A.13 The ICMP Statement
On systems without the BSD routing socket, GATED listens to ICMP messages
received by the system. GATED currently supports router discovery as well
as redirect. Processing of ICMP redirect messages is handled by the redirect
statement.
Use the ICMP statement to trace the ICMP messages that GATED receives.
The following ICMP statement specifies the tracing options for ICMP.
icmp {
traceoptions trace_options ;
}
traceoptions trace_options ;
A.13.1 Tracing Options
Packet tracing options (which may be modified with detail and recv ):
packets All ICMP packets received.
redirect Only ICMP REDIRECT packets received.
routerdiscovery Only ICMP ROUTER DISCOVERY packets received.
info
Only ICMP informational packets, which include mask
request/response, info request/response, echo request/response
and time stamp request/response.
error Only ICMP error packets, which include time exceeded,
parameter problem, unreachable and source quench.
A–18 Gateway Routing Daemon (GATED) Configuration Reference