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DNS packets trigering the isdn (DOD)

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3 replies

by deepa_scorp26

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I have a isdn DOD connection.
There are some dns packets which keeps triggering the isdn and gets connected.
For testing purpose i disconnected all the lan connection (not even a PC) form the router,except the T0(ISDN-DOD).Still there are some DNS packets which keeps on triggering.What could be the possible cause...

regards
Deepa K

3 replies

by hackersforum

hi deepa
first of all check that whether DNS server which is used for resolving DNS queries is inside the domain. ie inside the iner interface of the Router. DNS queries from an ISP will always trigger an connection.
For minimising the queries configure a local Caching only DNS server.
Hope this will help.
cheers!

by nico baggus

Try to findout with tcpdump or ethereal what
traffic is causing the dialup.

With netfilter (iptables) you can make a filter
that is applicable when the link is down and on
that is applicable when the link is up and
swifth the forward/output chains between the up
and down versions.

HIH,

Kind regards,
Nico Baggus

by deepa_scorp26

blocking the packets using firewall is a second issue...i want to knw wat causes this triggering...when i checked even the open tcp due to previous connection.there is no more such type of connection either.
then finally i made changes in named.conf ,which blocked further querying of the forward address in forwarders.

Now its the XNS packets, which triggers , what could be the cause for the generation of these types of packets....

Firewall will help out to block them ,but i want to what proccess will generate all these unwanted packets....

regards
Deepa K

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