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<TITLE>RE: [j-nsp] Filtering OSPF routes</TITLE>
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<P><FONT SIZE=2>Wayne, </FONT>
<BR><FONT SIZE=2> </FONT>
<BR><FONT SIZE=2>I have seen this in action, and it is ugly.</FONT>
<BR><FONT SIZE=2> </FONT>
<BR><FONT SIZE=2>I recently had to work on a Cisco network where all routers were in</FONT>
<BR><FONT SIZE=2>one of two areas, and they were using the distribute-lists to only</FONT>
<BR><FONT SIZE=2>use the 0/0 LSA. This created many routing loops, and I asked the</FONT>
<BR><FONT SIZE=2>"designer" what they were thinking, and basically got the cold</FONT>
<BR><FONT SIZE=2>shoulder. I couldn't understand why someone would want to use OSPF</FONT>
<BR><FONT SIZE=2>and then deliberately break it in that manner.</FONT>
<BR><FONT SIZE=2> </FONT>
<BR><FONT SIZE=2>Has anyone on this list ever seen a good reason to filter LSAs?</FONT>
<BR><FONT SIZE=2> </FONT>
<BR><FONT SIZE=2>- -andrew</FONT>
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<P><FONT SIZE=2>- -----Original Message-----</FONT>
<BR><FONT SIZE=2>From: Wayne (juniper nsp) [<A HREF="mailto:wg-jnpr-nsp@wgustavus.com">mailto:wg-jnpr-nsp@wgustavus.com</A>] </FONT>
<BR><FONT SIZE=2>Sent: Saturday, February 15, 2003 11:43 PM</FONT>
<BR><FONT SIZE=2>To: Ben Buxton; Ajay Bhardwaj; juniper-nsp@puck.nether.net</FONT>
<BR><FONT SIZE=2>Subject: Re: [j-nsp] Filtering OSPF routes</FONT>
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<P><FONT SIZE=2>Actually, if you are running a sufficiently high enough version of</FONT>
<BR><FONT SIZE=2>IOS (e.g. 12.0S), the 7200 can filter some LSAs. It depends on your</FONT>
<BR><FONT SIZE=2>exact scenario if this will accomplish what you are trying to do. It</FONT>
<BR><FONT SIZE=2>does tend to go contrary to the design of OSPF (or any link state</FONT>
<BR><FONT SIZE=2>protocol), but I suppose enough people wanted the knob, so they got</FONT>
<BR><FONT SIZE=2>it.</FONT>
<BR><FONT SIZE=2> </FONT>
<BR><FONT SIZE=2>Not sure if JUNOS has a similar knob.</FONT>
<BR><FONT SIZE=2> </FONT>
<BR><FONT SIZE=2>- - Wayne </FONT>
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<P><FONT SIZE=2>- ----- Original Message ----- </FONT>
<BR><FONT SIZE=2>From: Ben Buxton </FONT>
<BR><FONT SIZE=2>To: Ajay Bhardwaj ; juniper-nsp@puck.nether.net </FONT>
<BR><FONT SIZE=2>Sent: Monday, February 10, 2003 4:18 AM</FONT>
<BR><FONT SIZE=2>Subject: RE: [j-nsp] Filtering OSPF routes</FONT>
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<P><FONT SIZE=2> </FONT>
<BR><FONT SIZE=2>You cannot filter OSPF. This would break the requirement that all</FONT>
<BR><FONT SIZE=2>routers have</FONT>
<BR><FONT SIZE=2>the same link state view.</FONT>
<BR><FONT SIZE=2>This is true for both Junos and IOS.</FONT>
<BR><FONT SIZE=2> </FONT>
<BR><FONT SIZE=2>BB</FONT>
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<P><FONT SIZE=2>- -----Original Message-----</FONT>
<BR><FONT SIZE=2>From: Ajay Bhardwaj [<A HREF="mailto:ajay.bhardwaj@in.spectranet.com">mailto:ajay.bhardwaj@in.spectranet.com</A>] </FONT>
<BR><FONT SIZE=2>Sent: Monday, 10 February 2003 08:39</FONT>
<BR><FONT SIZE=2>To: juniper-nsp@puck.nether.net</FONT>
<BR><FONT SIZE=2>Subject: [j-nsp] Filtering OSPF routes</FONT>
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<P><FONT SIZE=2>Hi all,</FONT>
<BR><FONT SIZE=2> </FONT>
<BR><FONT SIZE=2>We have cisco 7200 router and M-5 router both running ospf and part</FONT>
<BR><FONT SIZE=2>of area 10.</FONT>
<BR><FONT SIZE=2> </FONT>
<BR><FONT SIZE=2>I want to deny few routes which are flowing trough ospf from 7200 to</FONT>
<BR><FONT SIZE=2>m5 either at 7200 side or m5 side. Pls if anyone have any solution to</FONT>
<BR><FONT SIZE=2>this would be gr8 help for me.</FONT>
<BR><FONT SIZE=2> </FONT>
<BR><FONT SIZE=2>Ajay Bhardwaj</FONT>
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<P><FONT SIZE=2> _____ </FONT>
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