| 33.6. OSPF External Routes filter table | ||
|---|---|---|
 | Chapter 33. OSPF - Open Shortest Path First |  |
| 33.6. OSPF External Routes filter table | ||
|---|---|---|
| | Chapter 33. OSPF - Open Shortest Path First | |
The table of OSPF External Routes contains information about filtering rules for routes which are external to the OSPF domain and which could be imported into the OSPF domain.
This table is used only when this router is declared as ASBR
(ASBR:YES).
The table of OSPF External Routes is used as follows:
An empty table is a “default accept” table.
A table with only “ignore” records is still a “default accept” table.
A table with at least one “accept” record for a protocol becomes a “default ignore” for that protocol.
In the first case, the filtering is possible only “by
protocol” (through the parameters LOCAL,
STATIC and RIP).
In the second case, routes are ignored.
In the third case, all the routes for the protocol having at least one “accept” record are ignored, except those explicitly accepted.
Commands for managing the table of OSPF External Routes are the following:
This command shows the content of the Table of OSPF External Routes.
[16:45:23] ABILIS_CPX:d ospf external
-----------------------------------------------------
EXTERNAL: PROT: ACTION: METRIC: TYPE:
-----------------------------------------------------
192.168.006.002/32 RIP ACCEPT 5 1
192.168.006.000/24 LOCAL IGNORE 1 1
010.000.000.000/08 STATIC ACCEPT 10 1
000.000.000.000/00 ANY IGNORE * 1
-----------------------------------------------------Meaning of the parameters:
EXTERNALIt specifies the external IP network that can be imported (or not) into OSPF resource. External network IP address and mask in Slash Notation [0.0.0.0, 1-126.x.x.x, 127.0.0.1, 128-223.x.x.x]/[0..32].
PROTThis parameter defines a routing protocol for which this
filter will be applied [ANY,
LOCAL, STATIC,
RIP];
ACTIONThis parameter indicates if the selected network can be
accepted or ignored by OSPF resource [IGNORE:
do not distribute this IP addresses into OSPF;
ACCEPT: distribute this IP addresses into
OSPF]. This means that all the routing present in the IP Routings
table which matches will be imported to OSPF table in case that is
set to ACCEPT (and then will be used also
specified metric), and will be not imported in case that it is set
to IGNORE.
METRICThis parameter sets the metric value that will be used for
redistribution routes, of LOCAL,
STATIC or RIP type, imported
from the IP Routings table into OSPF. The value
* stands for “use default
metric”.
TYPEType of external route [1, 2].
The allowed syntax of the command is:
d ospf external: it shows the table.
d ospf external:x.x.x.x/yy PROT:val: it shows the specified entry.
It adds a new entry to the Table of OSPF External Routes.
The syntax of the command is:
a OSPF external:x.x.x.x/yy prot:val action:val [metric:val]
Example: add a rule to accept the OSPF packets for the net 192.168.5.0/24 (static routing) and assign to it the exporting metric value 5.
[16:19:36] ABILIS_CPX:a ospf external:192.168.5.0/24 prot:static action:accept metric:5COMMAND EXECUTED [16:54:47] ABILIS_CPX:d ospf external- Not Saved (SAVE CONF), Not Refreshed (INIT) --------------------------------- ----------------------------------------------------- EXTERNAL: PROT: ACTION: METRIC: TYPE: ----------------------------------------------------- 192.168.006.002/32 RIP ACCEPT 5 1 192.168.005.000/24 STATIC ACCEPT 5 1 192.168.006.000/24 LOCAL IGNORE 1 1 010.000.000.000/08 STATIC ACCEPT 10 1 000.000.000.000/00 ANY IGNORE * 1 -----------------------------------------------------
It deletes the OSPF external route entry identified by the specified mandatory parameters.
The syntax of the command is:
c OSPF external:x.x.x.x/yy prot:val
Example: clear the entry added in the previous paragraph.
[16:54:47] ABILIS_CPX:d ospf external- Not Saved (SAVE CONF), Not Refreshed (INIT) --------------------------------- ----------------------------------------------------- EXTERNAL: PROT: ACTION: METRIC: TYPE: ----------------------------------------------------- 192.168.006.002/32 RIP ACCEPT 5 1 192.168.005.000/24 STATIC ACCEPT 5 1 192.168.006.000/24 LOCAL IGNORE 1 1 010.000.000.000/08 STATIC ACCEPT 10 1 000.000.000.000/00 ANY IGNORE * 1 ----------------------------------------------------- [16:55:02] ABILIS_CPX:c ospf external:192.168.5.0/24 prot:staticCOMMAND EXECUTED [16:56:11] ABILIS_CPX:d ospf external- Not Saved (SAVE CONF), Not Refreshed (INIT) --------------------------------- ----------------------------------------------------- EXTERNAL: PROT: ACTION: METRIC: TYPE: ----------------------------------------------------- 192.168.006.002/32 RIP ACCEPT 5 1 192.168.006.000/24 LOCAL IGNORE 1 1 010.000.000.000/08 STATIC ACCEPT 10 1 000.000.000.000/00 ANY IGNORE * 1 -----------------------------------------------------
It sets new values of the parameters of the OSPF external route entry.
The syntax of the command is:
s OSPF external:x.x.x.x/yy prot:val par:val [par:val...]
Example: change the metric value to an already existing entry.
[16:57:24] ABILIS_CPX:d ospf external- Not Saved (SAVE CONF), Not Refreshed (INIT) --------------------------------- ----------------------------------------------------- EXTERNAL: PROT: ACTION: METRIC: TYPE: ----------------------------------------------------- 192.168.006.002/32 RIP ACCEPT 5 1 192.168.005.000/24 STATIC ACCEPT 5 1 192.168.006.000/24 LOCAL IGNORE 1 1 010.000.000.000/08 STATIC ACCEPT 10 1 000.000.000.000/00 ANY IGNORE * 1 ----------------------------------------------------- [16:57:30] ABILIS_CPX:s ospf external:192.168.5.0/24 prot:static action:accept metric:3COMMAND EXECUTED [16:57:35] ABILIS_CPX:d ospf external- Not Saved (SAVE CONF), Not Refreshed (INIT) --------------------------------- ----------------------------------------------------- EXTERNAL: PROT: ACTION: METRIC: TYPE: ----------------------------------------------------- 192.168.006.002/32 RIP ACCEPT 5 1 192.168.005.000/24 STATIC ACCEPT 3 1 192.168.006.000/24 LOCAL IGNORE 1 1 010.000.000.000/08 STATIC ACCEPT 10 1 000.000.000.000/00 ANY IGNORE * 1 -----------------------------------------------------
| |  | |
| 33.5. OSPF Areas table |  | 33.7. OSPF Hosts table |