[dns-operations] latest bind, EDNS & TCP

[Simon Munton]

>> My big concern is if this is an issue in a new release of bind,
>
> Which new release of BIND?

I guess from whatever version starts from bufsize=512, instead of 
bufsize=4096 - I don't follow bind source that closely.


I've attached (if this mailing list supports attachments?) an example of 
two queries 0.5 seconds apart that demonstrates the phenomenon.

They come from the same resolver and are into the same zone (dot-IN), so 
if it was going to learn a larger bufsize, it should have done so.

In both cases, the TCP session start 0.001 seconds after the UDP reply 
went out - so there can be little doubt this is in response to TC=1, as 
opposed to a time-out.
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09:46:47.173739 IP 213.162.69.168.8399 > 194.0.1.7.53: 8503 [1au] A? www.dell.co.in. (43)
09:46:47.173829 IP 194.0.1.7.53 > 213.162.69.168.8399: 8503-| 0/2/1 (90)
09:46:47.174764 IP 213.162.69.168.40581 > 194.0.1.7.53: Flags [S], seq 3470914970, win 14600, options [mss 1460,sackOK,TS val 256870591 ecr 0,nop,wscale 7], length 0
09:46:47.174786 IP 194.0.1.7.53 > 213.162.69.168.40581: Flags [S.], seq 2996415289, ack 3470914971, win 4344, options [mss 1460,sackOK,TS val 3451744005 ecr 256870591,nop,wscale 7], length 0
09:46:47.175607 IP 213.162.69.168.40581 > 194.0.1.7.53: Flags [.], ack 1, win 115, options [nop,nop,TS val 256870591 ecr 3451744005], length 0
09:46:47.175654 IP 213.162.69.168.40581 > 194.0.1.7.53: Flags [P.], ack 1, win 115, options [nop,nop,TS val 256870591 ecr 3451744005], length 4558862 [1au][|domain]
09:46:47.175662 IP 194.0.1.7.53 > 213.162.69.168.40581: Flags [.], ack 46, win 34, options [nop,nop,TS val 3451744006 ecr 256870591], length 0
09:46:47.175851 IP 194.0.1.7.53 > 213.162.69.168.40581: Flags [P.], ack 46, win 34, options [nop,nop,TS val 3451744006 ecr 256870591], length 60258862-[|domain]
09:46:47.176663 IP 213.162.69.168.40581 > 194.0.1.7.53: Flags [.], ack 603, win 124, options [nop,nop,TS val 256870591 ecr 3451744006], length 0
09:46:47.176802 IP 213.162.69.168.40581 > 194.0.1.7.53: Flags [F.], seq 46, ack 603, win 124, options [nop,nop,TS val 256870591 ecr 3451744006], length 0
09:46:47.176824 IP 194.0.1.7.53 > 213.162.69.168.40581: Flags [F.], seq 603, ack 47, win 34, options [nop,nop,TS val 3451744007 ecr 256870591], length 0
09:46:47.177652 IP 213.162.69.168.40581 > 194.0.1.7.53: Flags [.], ack 604, win 124, options [nop,nop,TS val 256870591 ecr 3451744007], length 0
09:46:47.620204 IP 213.162.69.168.5880 > 194.0.1.7.53: 23607 [1au] A? www.webnettechnology.in. (52)
09:46:47.620261 IP 194.0.1.7.53 > 213.162.69.168.5880: 23607-| 0/2/1 (99)
09:46:47.621193 IP 213.162.69.168.55340 > 194.0.1.7.53: Flags [S], seq 554306569, win 14600, options [mss 1460,sackOK,TS val 256870702 ecr 0,nop,wscale 7], length 0
09:46:47.621215 IP 194.0.1.7.53 > 213.162.69.168.55340: Flags [S.], seq 2999808062, ack 554306570, win 4344, options [mss 1460,sackOK,TS val 3451744451 ecr 256870702,nop,wscale 7], length 0
09:46:47.622064 IP 213.162.69.168.55340 > 194.0.1.7.53: Flags [.], ack 1, win 115, options [nop,nop,TS val 256870703 ecr 3451744451], length 0
09:46:47.622094 IP 213.162.69.168.55340 > 194.0.1.7.53: Flags [P.], ack 1, win 115, options [nop,nop,TS val 256870703 ecr 3451744451], length 5456660 [1au][|domain]
09:46:47.622103 IP 194.0.1.7.53 > 213.162.69.168.55340: Flags [.], ack 55, win 34, options [nop,nop,TS val 3451744452 ecr 256870703], length 0
09:46:47.622257 IP 194.0.1.7.53 > 213.162.69.168.55340: Flags [P.], ack 55, win 34, options [nop,nop,TS val 3451744452 ecr 256870703], length 59756660-[|domain]
09:46:47.623083 IP 213.162.69.168.55340 > 194.0.1.7.53: Flags [.], ack 598, win 124, options [nop,nop,TS val 256870703 ecr 3451744452], length 0
09:46:47.623237 IP 213.162.69.168.55340 > 194.0.1.7.53: Flags [F.], seq 55, ack 598, win 124, options [nop,nop,TS val 256870703 ecr 3451744452], length 0
09:46:47.623258 IP 194.0.1.7.53 > 213.162.69.168.55340: Flags [F.], seq 598, ack 56, win 34, options [nop,nop,TS val 3451744453 ecr 256870703], length 0
09:46:47.624056 IP 213.162.69.168.55340 > 194.0.1.7.53: Flags [.], ack 599, win 124, options [nop,nop,TS val 256870703 ecr 3451744453], length 0