On 2018/10/16 16:12, Henrik Lund Kramshøj wrote:

Looks like the email got held up somewhere, only just received on the 19th.

> "Fun fact, Unbound on OpenBSD reply to DNS requests received in Ethernet
> packets with broadcast destination and IP destination being the IP of
> the server}

That is normal behaviour from the IP stack, it isn't specific to unbound
or OpenBSD.

> My script using Scapy was something like the below, but you can 
> probably just use, if on same subnet:
> ...
> packet=Ether(dst=broadcastmac,src=randommac)/IP(src=attacker,
> dst=destination)/UDP(sport=testport,dport=insideport)/DNS(rd=1,id=0xdead,qd=DNSQR(qname="www.wikipedia.org"))
> sendp(packet,loop=0)
> 
> without the VXLAN header.

For easier testing, you can also use "arp -s $ip_address ff:ff:ff:ff:ff:ff"
on the machine you are trying to connect from - you can make all sorts of
connection and they still work. For example, making an ssh connection
to a Linux box also succeeds with a broadcast destination MAC.

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