Find Sender of Route Request

[Ahmad Haghighi <[e-mail]>]

​​Hello

I'm working on MANET security and Blackhole/Grayhole detection.
I have a question, so please help me, or  If you have little time and so
can't answer me, please refer me to some people or book for finding my
answer. my question is:
*In MANET (with DSR or AODV) when a Route Reply (RREP) packet received by
the source node, the source node can not be sure who is the sender of RREP,*
 (*it is a assumption in all papers*) so source node (the node which
initiated Route Discovery) should do some operations for detecting exact
address of Malicious node (sender of malicious RREP).
But e.g. in DSR Header we have a "Source Address" field which carries
address of sender. or also in IP header of ADOV RREP.
I don't understand why source node is *not sure* about identity of sender
of RREP?
I don't know the reason of above assumption.

Let me explain my question more oblivious.
Source node, receive a malicious RREP, the source node use it's path for
sending packets. As expected Malicious node drops all packets.
Ok.
Now we want to find malicious node (sender of RREP), If value of "Source
Address" Was reliable, we be able to easily find malicious node (sender of
RREP).
But in all papers, authors employs some mechanisms for detecting malicious
node (sender of RREP). so we can conclude value of "Source address"
field is not reliable.
My question is, why? why source node can not use this field for detecting
and removing malicious node?
One answer is because of IP Spoofing i.e malicious node can use another
address as source address
but this not the only reason, I need to find another reason for that

I hardly need the answer.
So please guide me
Thanks