Am 15.09.2017 um 09:37 schrieb Harshith Mulky: > Hello Experts, > > I had a query on advertising the payload size on client in DNS Responses > over UDP/TCP > > > This is as much I have understood from RFC 6891, that a > requester(client) can address his capabilities to restrict the UDP > Payload size to a limit between 512 to 4096 bytes based on his > limitation when supporting EDNS Procedures. > > Is it the same case with TCP? > > Can we(client) advertize our capabilities over TCP to limit the payload > size in Responses?
why would you want do do that? TCP don't suffer from the problem of a faked sourcip and the repsonse going back to the attacke victim! what do you imagine to happen when your response data is larger? in case of UDP the fallback is simply TCP and then you want to cripple that fallback? [Harshith] But I do not understand why would OPT section required in a TCP Query. As i see from my Traces, Even TCP Queries carry a OPT section with the advertized sizes the client supports! Why would this be necessary? I do not want to cripple the fallback, but if a query is intending to do so from a resolver, how Do we stop that? Thanks ________________________________ From: bind-users <bind-users-boun...@lists.isc.org> on behalf of bind-users-requ...@lists.isc.org <bind-users-requ...@lists.isc.org> Sent: Friday, September 15, 2017 5:30 PM To: bind-users@lists.isc.org Subject: bind-users Digest, Vol 2734, Issue 2 Send bind-users mailing list submissions to bind-users@lists.isc.org To subscribe or unsubscribe via the World Wide Web, visit https://lists.isc.org/mailman/listinfo/bind-users or, via email, send a message with subject or body 'help' to bind-users-requ...@lists.isc.org You can reach the person managing the list at bind-users-ow...@lists.isc.org When replying, please edit your Subject line so it is more specific than "Re: Contents of bind-users digest..." Today's Topics: 1. Re: What is wrong with my second $ORIGIN (Harshith Mulky) 2. Re: Is there a need for clients to advertize the capabilities for DNS Responses over TCP (Reindl Harald) ---------------------------------------------------------------------- Message: 1 Date: Fri, 15 Sep 2017 01:16:08 -0700 (MST) From: Harshith Mulky <harshith.mu...@outlook.com> To: bind-users@lists.isc.org Subject: Re: What is wrong with my second $ORIGIN Message-ID: <1505463368415-0.p...@n4.nabble.com> Content-Type: text/plain; charset=us-ascii Than you All. Did not notice I had missed a trailing '.' Will make sure I do not miss these things the next time I test -- Sent from: http://bind-users-forum.2342410.n4.nabble.com/ ------------------------------ Message: 2 Date: Fri, 15 Sep 2017 12:30:23 +0200 From: Reindl Harald <h.rei...@thelounge.net> To: bind-users@lists.isc.org Subject: Re: Is there a need for clients to advertize the capabilities for DNS Responses over TCP Message-ID: <ac3458f0-305d-fc4f-868b-bd5ffed1f...@thelounge.net> Content-Type: text/plain; charset=windows-1252; format=flowed Am 15.09.2017 um 09:37 schrieb Harshith Mulky: > Hello Experts, > > I had a query on advertising the payload size on client in DNS Responses > over UDP/TCP > > > This is as much I have understood from RFC 6891, that a > requester(client) can address his capabilities to restrict the UDP > Payload size to a limit between 512 to 4096 bytes based on his > limitation when supporting EDNS Procedures. > > Is it the same case with TCP? > > Can we(client) advertize our capabilities over TCP to limit the payload > size in Responses? why would you want do do that? TCP don't suffer from the problem of a faked sourcip and the repsonse going back to the attacke victim! what do you imagine to happen when your response data is larger? in case of UDP the fallback is simply TCP and then you want to cripple that fallback? ------------------------------ Subject: Digest Footer _______________________________________________ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users ------------------------------ End of bind-users Digest, Vol 2734, Issue 2 *******************************************
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