Re: Request for review of performance advice

2020-07-07 Thread Browne, Stuart via bind-users
Just one quick one before I run off to lunch with regards to section 2: - Try to avoid crossing NUMA boundaries. At high throughput, the context switching and far memory calls kills performance. Stuart From: bind-users on behalf of Victoria Risk Date: Wednesday, 8 July 2020 at 11:58 To:

Request for review of performance advice

2020-07-07 Thread Victoria Risk
A while ago we created a KB article with tips on how to improve your performance with our Kea dhcp server. The tips were fairly obvious to our developers and this was pretty successful. We would like to do something similar for BIND, provide a dozen or so tips for how to maximize your

Re: rndc valid key types

2020-07-07 Thread Evan Hunt
On Tue, Jul 07, 2020 at 04:32:37PM -0700, Gregory Sloop wrote: > I've seen reports that only HMAC-MD5 is the only valid key type. That was the case at one time, but hasn't been for years. > Is there any (security) reason/implications to use something "better" > than MD5? MD5 is broken (as is

rndc valid key types

2020-07-07 Thread Gregory Sloop
So, I've spent some time looking at the man pages and googling without any definitive answer. I'm generating some new rndc keys for my bind9 config. (9.11.3 in this particular case, if it matters.) rndc-confgen has quite a number of options for the key-type - but I'm not sure what BIND9 will

Re: DNS security, amplification attacks and recursion

2020-07-07 Thread Brett Delmage
On Tue, 7 Jul 2020, Tony Finch wrote: Brett Delmage wrote: On Tue, 7 Jul 2020, Tony Finch wrote: minimal-any yes; Why only reduce and not eliminate? The reason is a bit subtle. If an ANY query comes via a recursive resolver, it is much better to give the resolver an answer so

Re: DNS security, amplification attacks and recursion

2020-07-07 Thread Tony Finch
Brett Delmage wrote: > On Tue, 7 Jul 2020, Tony Finch wrote: > > > > minimal-any yes; > > Why only reduce and not eliminate? The reason is a bit subtle. If an ANY query comes via a recursive resolver, it is much better to give the resolver an answer so that it will put an entry in its cache.

Re: DNS security, amplification attacks and recursion

2020-07-07 Thread @lbutlr
On 07 Jul 2020, at 12:06, Michael De Roover wrote: > On 7/7/20 4:06 PM, Tony Finch wrote: > >> max-udp-size 1420; >> https://dnsflagday.net/2020/ > Interesting, I wasn't aware of this campaign. I don't know if I'm > knowledgeable enough on UDP to be able to make educated decisions on

Re: DNS security, amplification attacks and recursion

2020-07-07 Thread Brett Delmage
On Tue, 7 Jul 2020, Shumon Huque wrote: Cloudflare themselves now implement the "minimal any" behavior described in this spec:     https://tools.ietf.org/html/rfc8482 cloudflare.com.         3789    IN      HINFO   "RFC8482" "" Gee, that's a pretty minimal answer!

Re: DNS security, amplification attacks and recursion

2020-07-07 Thread Shumon Huque
On Tue, Jul 7, 2020 at 2:21 PM Brett Delmage wrote: > On Tue, 7 Jul 2020, Tony Finch wrote: > > > Reduce the size of responses to ANY queries, which are a favourite tool > of > > amplification attacks. There's basically no downside to this one, in my > > opinion, but I'm biased because I

Re: DNS security, amplification attacks and recursion

2020-07-07 Thread Brett Delmage
On Tue, 7 Jul 2020, Tony Finch wrote: Reduce the size of responses to ANY queries, which are a favourite tool of amplification attacks. There's basically no downside to this one, in my opinion, but I'm biased because I implemented it. minimal-any yes; Why only reduce and not

Re: DNS security, amplification attacks and recursion

2020-07-07 Thread Michael De Roover
On 7/7/20 4:06 PM, Tony Finch wrote: An auth-only server can also be used for amplification attacks that use its authoritative zones - these attacks don't have to use recursion. There are a few ways to mitigate auth-only amplification attacks. Response rate limiting is very effective. Start

Re: DNS security, amplification attacks and recursion

2020-07-07 Thread Tony Finch
@lbutlr wrote: > > > rate-limit { responses-per-second 10; }; > > Does that apply to local queries as well (for example, a mail server may > easily make a whole lot of queries to 127.0.0.1, and rate limiting it > would at the very least affect logging and could delay mail if the MTA > cannot

Canadian registrars that properly support ipv6 and DNSSEC ?

2020-07-07 Thread Brett Delmage
Not quite on-topic, but consider this an essential element of making my BIND signing, authoritative server and name service work well. Does anyone know of or ideally have experience with Canadian (CIRA-authorized) and ideally _Canadian-based_ .ca registrars that handle DNSSEC and ipv6

Re: Fun with nsudpate and ac1.nstld.com

2020-07-07 Thread Tony Finch
@lbutlr wrote: > > The latest surprise was that dnssec-enable yes; is obsolete in Bind 9.16. `dnssec-enable yes` has been the default since 2007, so that directive has been useless for quite a long time :-) What changed in 9.16 is that you now can't turn DNSSEC off. (Specifically, support for

Re: DNS security, amplification attacks and recursion

2020-07-07 Thread @lbutlr
On 07 Jul 2020, at 08:06, Tony Finch wrote: Excellent post, and a nice summary of some best practices. I have a couple of questions. > Response rate limiting is very effective. Start off by putting the > following in your options{} section, and look in the BIND ARM for other > directives you

Re: Fun with nsudpate and ac1.nstld.com

2020-07-07 Thread @lbutlr
On 06 Jul 2020, at 17:59, Mark Andrews wrote: > Nsupdate can normally determine the name of the zone that has to be updated > so most of the time you don’t need to specify the zone. There are a few > cases, like when adding delegating NS records or glue to the parent zone you > have to

Re: DNS security, amplification attacks and recursion

2020-07-07 Thread Tony Finch
Michael De Roover wrote: > > Said friend said to me that he tested my authoritative name servers and > found them to be not vulnerable. [snip] They do not respond to recursive > queries. It appears that the test of whether a server is "vulnerable" or > not has to do with this. The command used to

Re: DNS security, amplification attacks and recursion

2020-07-07 Thread Stephane Bortzmeyer
On Tue, Jul 07, 2020 at 03:00:13PM +0200, Michael De Roover wrote a message of 46 lines which said: > The command used to test this was apparently "dig +short > test.openresolver.com TXT @your.name.server". ANY instead of TXT may be more efficient (specially with +dnssec), if the goal is to

DNS security, amplification attacks and recursion

2020-07-07 Thread Michael De Roover
Hello, Recently I discussed with a friend of mine the idea of NTP and DNS in the context of denial of service attacks. In NTP this amplification attack is done with the monlist command (that should honestly never have been publicly available due to its purpose being pretty much entirely