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Tweaking the DNS response

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# 1  
Old 08-26-2013
Tweaking the DNS response
Hi All,

The following is the scenario.

I open the browser and request a web page. The DNS query is sent to the DNS server of my company and replies my GNU/Linux machine with a DNS response. I have "insmod"ed a kernel module that picks up the DNS response and over rides the "Addr" field of the "Answers" Section of the DNS response packet with a different IP address. However, after overriding the "Addr" field, my machine sends a ICMP(Host unreachable, administratively probihited) msg to the DNS server.
Can some one throw light on what is happening.


I am using netfilter frame work in my module and tweaking the DNS response in the NF_INET_PRE_ROUTING hook.

I m attaching the wireshark pcap.
192.168.180.29 - IP of my machine.
192.168.164.12 - DNS server IP.


Thank You.
roy
ne.edu_sdnat.gz (60.6 KB) 
# 2  
Old 08-26-2013
Attachment?
Not sure what your attachment is, but I know many WILL NOT open an attachment to look at a problem.
1) Lots of extra steps
2) Security issues
This User Gave Thanks to joeyg For This Post:
rstnsrr
# 3  
Old 08-27-2013
Hi joeyg,

Can u please elaborate your points?


Regards,
Roy
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