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<div>Actually, not all DNS queries fail to receive a response—only some do, especially for domains starting with "www".</div><div>The only difference of query packets between version 2.91 and version 2.90 is EDNS0 header. </div><div><br></div><div>Perplexing ISP firewall.</div><hr style="width: 210px; height: 1px;" color="#b5c4df" size="1" align="left">
<div><span><div style="MARGIN: 10px; FONT-FAMILY: verdana; FONT-SIZE: 10pt"><div>zhangguodong@robustel.com</div></div></span></div>
<blockquote style="margin-Top: 0px; margin-Bottom: 0px; margin-Left: 0.5em; margin-Right: inherit"><div> </div><div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm"><div style="PADDING-RIGHT: 8px; PADDING-LEFT: 8px; FONT-SIZE: 12px;FONT-FAMILY:tahoma;COLOR:#000000; BACKGROUND: #efefef; PADDING-BOTTOM: 8px; PADDING-TOP: 8px"><div><b>From:</b> <a href="mailto:uhlar@fantomas.sk">Matus UHLAR - fantomas</a></div><div><b>Date:</b> 2025-12-23 19:36</div><div><b>To:</b> <a href="mailto:dnsmasq-discuss@lists.thekelleys.org.uk">dnsmasq-discuss</a></div><div><b>Subject:</b> Re: [Dnsmasq-discuss] Add an option to not always add a pseudo header?</div></div></div><div><div>On 23.12.25 17:48, zhangguodong--- via Dnsmasq-discuss wrote:</div>
<div>>I'm using dnsmasq as a local caching resolver for several years and upgrade to version 2.91 recently. It used to work properly in the past, but the queries to dnsmasq can not be replied now.</div>
<div>>I have confirmed that my home broadband provider's firewall is blocking query packets with the EDNS0 header, based on a comparison between versions 2.91 and 2.90.</div>
<div>>From the changelog of version 2.91, I also learn that EDNS0 header will be always added when talking to upstream now.</div>
<div> </div>
<div>Have you tried to handle this with your provider?</div>
<div> </div>
<div>EDNS is 25 years old (RFC 2671, August 1999) and required for many </div>
<div>functionalities, especially since many DNS replies are bigger than the old </div>
<div>512B maximum for DNS UDP packets.</div>
<div> </div>
<div> </div>
<div>>Therefore, is it possible to add an option to control whether to always add EDNS0 header?</div>
<div> </div>
<div>-- </div>
<div>Matus UHLAR - fantomas, uhlar@fantomas.sk ; http://www.fantomas.sk/</div>
<div>Warning: I wish NOT to receive e-mail advertising to this address.</div>
<div>Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu.</div>
<div>REALITY.SYS corrupted. Press any key to reboot Universe.</div>
<div> </div>
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</div></blockquote>
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