Hello,
I’m running unbound 1.0.2 on FreeBSD (7/amd64) without any problems, except this one.
Occasionally, unbound gives back very high TTLs, as can be seen here (reported by one of our users, while querying a local ISP’s DSL pool addresses randomly from the server in question):
; <<>> DiG 9.4.1-P1 <<>> dsl51B6D492.pool.t-online.hu.
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 10905
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 0
;; QUESTION SECTION:
;dsl51B6D492.pool.t-online.hu. IN A
;; ANSWER SECTION:
dsl51B6D492.pool.t-online.hu. 4294966839 IN A 81.182.212.146
;; AUTHORITY SECTION:
pool.t-online.hu. 86400 IN NS ans1.t-online.hu.
pool.t-online.hu. 86400 IN NS ans0.t-online.hu.
;; Query time: 2 msec
;; SERVER: 172.16.1.55#53(172.16.1.55)
;; WHEN: Fri Oct 10 14:55:48 2008
Wireshark says:
Answers
dsl51B6D492.pool.t-online.hu: type A, class IN, addr 81.182.212.146
Name: dsl51B6D492.pool.t-online.hu
Type: A (Host address)
Class: IN (0x0001)
Time to live: -7 minutes, -37 seconds
Data length: 4
Addr: 81.182.212.146
But it can be clearly seen that there is a signedness issue in wireshark, because the packet dump contains:
0030 00 01 00 02 00 00 0b 64 73 6c 35 31 42 36 44 34 …dsl51B6D4
0040 39 32 04 70 6f 6f 6c 08 74 2d 6f 6e 6c 69 6e 65 92.pool.t-online
0050 02 68 75 00 00 01 00 01 c0 0c 00 01 00 01 ff ff .hu…
0060 fe 37 00 04 51 b6 d4 92 c0 18 00 02 00 01 00 01 .7..Q…
The error doesn’t always pop up, but -according to the user- can be reproduced, because he could find some other occurances as well.
The server itself has two (Opteron) CPUs, and unbound runs without threading enabled (–without-pthreads). The server also runs openntpd, which should call adjtime to skew the clock if needed.
Another aspect, which can be relevant is that the host has kern.timecounter.hardware: TSC set, and TSC is said to be not synchronized across the CPUs, but I don’t think this could cause such a difference.
Any ideas about this?
Thanks,