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One potential solution involves implementing the use of intermediate
Internet gateways (i.e., those servers connecting disparate networks along the path followed by any given packet) filtering or denying any packet deemed to be illegitimate. The gateway processing the packet might simply ignore the
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of the computer that originally sent it. This allows devices in the receiving network to know where it came from, allowing a reply to be routed back (amongst other things), except when IP addresses are used through a proxy or a spoofed IP address, which does not pinpoint a specific user within that
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In ingress filtering, packets coming into the network are filtered if the network sending it should not send packets from the originating IP address(es). If the end host is a stub network or host, the router needs to filter all IP packets that have, as the source IP,
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Any router that implements ingress filtering checks the source IP field of IP packets it receives and drops packets if the packets don't have an IP address in the IP address block to which the interface is connected. This may not be possible if the end host is
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As of 2012, one report suggests that, contrary to general opinion about the lack of BCP 38 deployment, some 80% of the
Internet (by various measures) were already applying anti-spoofing packet filtering in their networks.
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At least one computer security expert is in favor of passing a law requiring 100% of all ISPs to implement network ingress filtering as defined in IETF BCP 38. In the US, presumably the
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of IP connectivity filter packets entering their networks from downstream customers, and discard any packets which have a source address that is not allocated to that customer.
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are one example of technical engineering applications that help to identify, prevent and/or deter unwanted, unsuspected or suspicious events and intrusions.
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packet completely, or where possible, it might send a packet back to the sender relaying a message that the illegitimate packet has been denied.
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Chapter 23 in Hutt, Bosworth, and Hoytt (1995) "Computer
Security Handbook, Third Edition", Wiley, section 23.6(b), pp 23-12, et seq.
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There are many possible ways of implementing this policy; one common mechanism is to enable
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are actually from the networks from which they claim to originate. This can be used as a
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on links to customers, which will indirectly apply this policy based on the provider's
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Networks receive packets from other networks. Normally a packet will contain the
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in BCP 38 and 84, which are defined by RFC 2827 and RFC 3704, respectively.
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policy that relies on cooperation between ISPs for their mutual benefit.
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or addresses that do not have the same network address as the interface.
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of
Internet traffic, and thus indirectly combat various types of
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404:"What laws should be created to improve computer security?"
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2019 IEEE Conference on
Network Softwarization (NetSoft)
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Network ingress filtering makes it much easier to track
501:"Everyone should be deploying BCP 38! Wait, they are …"
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for network ingress filtering are documented by the
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by making
Internet traffic traceable to its source.
49:. Unsourced material may be challenged and removed.
528:Ingress Filtering for Multihomed Networks (BCP 84)
341:Zhauniarovich, Yury; Dodia, Priyanka (June 2019).
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131:is a technique used to ensure that incoming
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16:Computer network packet filtering technique
143:where the attacker's packets contain fake
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464:Ingress Filtering for Multihomed Networks
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246:to their source(s) so they can be fixed.
109:Learn how and when to remove this message
200:and also sends transit network traffic.
190:Host intrusion prevention systems (HIPS)
546:Information on BCP 84 » RFC Editor
541:Information on BCP 38 » RFC Editor
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461:Baker, F.; Savola, P. (March 2004).
423:Ferguson, P.; Senie, D. (May 2000).
47:adding citations to reliable sources
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167:A sender IP address can be faked (
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262:Internet Engineering Task Force
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229:Internet service providers
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566:Computer network security
244:denial-of-service attacks
221:Network ingress filtering
149:denial-of-service attacks
387:Security on the Internet
302:would enforce this law.
177:denial-of-service attack
385:Robert Gezelter (1995)
276:reverse-path forwarding
267:BCP 84 recommends that
227:technique used by many
402:Dr. David A. Wheeler.
258:best current practices
317:Ingress cancellation
282:of their customers'
171:), characterizing a
43:improve this article
284:route announcements
233:IP address spoofing
183:Potential solutions
125:computer networking
58:"Ingress filtering"
269:upstream providers
231:to try to prevent
532:Jay R. Ashworth.
364:978-1-5386-9376-6
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99:February 2014
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32:This article
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534:"BCP38.info"
503:. senki.org.
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41:Please help
36:verification
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198:multi-homed
409:2023-06-10
328:References
290:Deployment
161:IP address
69:newspapers
524:RFC
517:RFC
373:201621791
237:net abuse
560:Category
306:See also
216:Networks
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155:Problem
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359:ISBN
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