Messages in this thread | | | Date | Fri, 4 Feb 2000 16:50:28 -0800 | From | "David S. Miller" <> | Subject | Re: 2.3.4[1-2] incoming connections -- RPC |
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From: rct@gherkin.sa.wlk.com (Bob_Tracy) Date: Fri, 4 Feb 2000 16:32:20 -0600 (CST)
I guess that could be construed to be a security feature. However, it is troubling that there now seems to be a dependency on RPC that didn't exist prior to 2.3.41. Would someone "in the know" please explain the thinking on this to me? If this matter isn't worth the list's time, a private reply would be acceptable and very much appreciated.
The RPC dependency on your system was always there, the behavior of the older kernels just hid it from you.
Look, your system is trying to talk to the portmapped, almost certainly to attempt NIS lookups. You don't have the portmapper running and you probably don't use NIS at all right? Look into /etc/nsswitch.conf, I it is configuring your system to attempt to use NIS. Am I right?
The new behavior is staying, because the old behavior has very far reaching negative effects. Here is one case which the old behavior would allow to happen:
a) Program A does UDP request to an active port on remote machine b) Program A times out and goes away for whatever reason c) Program B starts and does UDP request to same machine on same remote port, using same local port d) Remote machine finally responds to Program A's request (either with an error or real response from the server on that port) e) Program B sees the response/error!
For high load systems doing DNS, this is deadly.
So fix the apps and configuration on your system people.
Later, David S. Miller davem@redhat.com
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