Greetings Rajkumar,
: I am going through the LARTC howto to understand how the iproute2
: works. But some concepts like Policy Routing, RPDB etc are not clear
: to me. I am pretty new to iproute, beeing using route command for
: long...
:
: From what I understand
:
: 1. rules (ip rule) tell how to select packets for routing and route (ip
: route) tell where to route the selected packets.
Rules can do a few different things:
- most significantly, a rule (in the RPDB) can select a routing table
based on the characteristics of the packet
- a rule can rewrite the source addresses on (outbound) packets
- a rule can be of type blackhole (effectively drop), prohibit (ICMP
prohibit) or unreachable (ICMP unreachable)
: 2. A collection of rules is RPDB
The collection of rules is the routing policy database (RPDB).
: 3. Policy routing is routing using rules.
In linux-think, yes, policy routing requires the use of rules (RPDB).
In more general terms, policy routing is a technique of routing based on
characteristics of a packet other than the destination address, which is
the only selection criteria in conventional routing systems.
: 4. rules can specify a packet on various parameters, like source dest,
: fwmark, interface etc...
True enough. I have written a little bit about the RPDB [0], but you may
find that Matthew Marsh's policy routing book is a good resource [1].
And if you need a crash course in how linux selects a route [2].
: 5. route can tell only dst interface or next hop.
[ diagram and description snipped ]
: I hope my dig is legible. This is what I want to do. I would much
: appreciate if some one can give a clear picture as to how iproute
: works.
I tried to understand what you were trying to do, but found myself
confused. Perhaps you don't need policy routing? Anyway, best of
luck...try describing the problem again, and maybe it'll be more obvious
to me (and others?) next time around.
-Martin
[0] http://linux-ip.net/html/routing-rpdb.html
http://linux-ip.net/html/ch-routing.html
[1] http://www.policyrouting.org/
[2] http://linux-ip.net/html/routing-selection.html
--
Martin A. Brown --- SecurePipe, Inc. --- mabrown@xxxxxxxxxxxxxx
_______________________________________________
LARTC mailing list / LARTC@xxxxxxxxxxxxxxx
http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/
