<div dir="ltr"><span style="font-family:arial,sans-serif;font-size:13px">I use unbound as local caching server.</span><div style="font-family:arial,sans-serif;font-size:13px">When query goes from my local unbound to provider with "OPT UDPsize=512" - there is no any response from provider. I tried to set different values for "edns-buffer-size" but it does not helped.</div>
<div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">I found that unbound tries to send queries with this option. After several attempts it send queries without this option and that it gets response from the provider. This leads to the significant delay in resolving.</div>
<div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">Is there and way to make unbound send queries without this option?</div><div style="font-family:arial,sans-serif;font-size:13px">
<br></div><div style="font-family:arial,sans-serif;font-size:13px">This is example from tcpdump:</div><div style="font-family:arial,sans-serif;font-size:13px">----</div><div style="font-family:arial,sans-serif;font-size:13px">
<div> 192.168.1.75.31273 > 85.21.192.3.53: [udp sum ok] 21532+% [1au] A? <a href="http://ya.ru/" target="_blank">ya.ru</a>. ar: . OPT UDPsize=512 OK (34)</div><div>17:23:25.336577 IP (tos 0x0, ttl 64, id 45283, offset 0, flags [none], proto UDP (17), length 62)</div>
<div> 192.168.1.75.23166 > 85.21.192.3.53: [udp sum ok] 57209+% [1au] A? <a href="http://ya.ru/" target="_blank">ya.ru</a>. ar: . OPT UDPsize=512 OK (34)</div><div>17:23:26.884201 IP (tos 0x0, ttl 64, id 45285, offset 0, flags [none], proto UDP (17), length 62)</div>
<div> 192.168.1.75.58082 > 213.234.192.8.53: [udp sum ok] 20104+% [1au] A? <a href="http://ya.ru/" target="_blank">ya.ru</a>. ar: . OPT UDPsize=512 OK (34)</div><div>17:23:29.938285 IP (tos 0x0, ttl 64, id 45286, offset 0, flags [none], proto UDP (17), length 62)</div>
<div> 192.168.1.75.54667 > 213.234.192.8.53: [udp sum ok] 18401+% [1au] A? <a href="http://ya.ru/" target="_blank">ya.ru</a>. ar: . OPT UDPsize=512 OK (34)</div><div>17:23:32.992060 IP (tos 0x0, ttl 64, id 45289, offset 0, flags [none], proto UDP (17), length 62)</div>
<div> 192.168.1.75.60379 > 85.21.192.3.53: [udp sum ok] 16464+% [1au] A? <a href="http://ya.ru/" target="_blank">ya.ru</a>. ar: . OPT UDPsize=512 OK (34)</div><div>17:23:36.045801 IP (tos 0x0, ttl 64, id 45290, offset 0, flags [none], proto UDP (17), length 62)</div>
<div> 192.168.1.75.39746 > 85.21.192.3.53: [udp sum ok] 38011+% [1au] A? <a href="http://ya.ru/" target="_blank">ya.ru</a>. ar: . OPT UDPsize=512 OK (34)</div><div>17:23:39.095634 IP (tos 0x0, ttl 64, id 45291, offset 0, flags [none], proto UDP (17), length 51)</div>
<div> 192.168.1.75.26679 > 85.21.192.3.53: [udp sum ok] 3546+ A? <a href="http://ya.ru/" target="_blank">ya.ru</a>. (23)</div><div>17:23:39.099508 IP (tos 0x68, ttl 56, id 50151, offset 0, flags [none], proto UDP (17), length 99)</div>
<div> 85.21.192.3.53 > 192.168.1.75.26679: [udp sum ok] 3546 q: A? <a href="http://ya.ru/" target="_blank">ya.ru</a>. 3/0/0 <a href="http://ya.ru/" target="_blank">ya.ru</a>. A 93.158.134.3, <a href="http://ya.ru/" target="_blank">ya.ru</a>. A 213.180.204.3,<a href="http://ya.ru/" target="_blank">ya.ru</a>. A 213.180.193.3 (71)</div>
</div><div style="font-family:arial,sans-serif;font-size:13px">---</div><div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">As soon as query was sent without this option (at 17:23:39.099508) - I get the response.</div>
<div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">Best regards,</div><div style="font-family:arial,sans-serif;font-size:13px">Denis</div></div>