[Pdns-users] Some issues with DNSDist version 1.1 beta

[Thao Nguyen]

Hi everyone,

I get some issues with DNSDist, could anyone help me?
My dnsdist rpm: dnsdist-1.1.0-0.1.beta1.1pdns.el7.x86_64.rpm
My OS: Redhat 7.2

*Issue 1*:

I tried to use feature "eBPF Socket Filtering" but it does not work as
example. Do I miss something? I can't find another example in internet.

[root at mymachine ~]# dnsdist -c
> bpf = newBPFFilter(1024, 1024, 1024)
Error: [string "bpf = newBPFFilter(1024, 1024, 1024)"]:1: attempt to call
global 'newBPFFilter' (a nil value):

I see it require  Linux kernels (4.1+). But the last kernel in Redhat 7 is
kernel-3.10.0-327.36.3.el7.x86_64. Can I use this feature ?

*Issue 2: *
showResponseLatency seen works normally. But, when I send a query with type
"axfr", the "Average response latency" increase to very big. Does it is a
bug?
The query time of dig "axfr" type is "Query time: 1 msec". If I continue
use "axfr" in dig, "Average response latency" look wrong.

> showResponseLatency()
> showResponseLatency()
Average response latency: 37364.53 msec
  msec
  0.10
  0.20
  0.40
**********************************************************************
  0.80
  1.60
  3.20
  6.40
 12.80
 25.60
 51.20
102.40
204.80
409.60
819.20
1638.40

Addition:
In case I never query(restart dnsdist), then I send a query with type
"axfr" , we will see below log if call showResponseLatency()

> showResponseLatency()
No traffic yet.
> showResponseLatency()
Error: Exception thrown by a callback function called by Lua:
basic_string::_S_create> showResponseLatency()

After this error, I sent a query without "axfr". I see the result is:
Average response latency: 149470.26 msec

*Issue 3:*
I tried to use addDeplay but I think it can not work with query "axfr"
type. Please let me know your thought.

addDelay("test.com.", 500)

Without "axfr": Query time: 501 msec
With "axfr": Query time: 41 msec (not deplayed)


I really like dnsdist-1.1.0-0.1, it works better than dnsdist 1.0 in Redhat
7 although it is Beta version.

Best regards,

Thao Nguyen
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