12 Oct
2017
12 Oct
'17
7:44 p.m.
Hi Pedro,
Funny thing..
If I do a reverse lookup up for 193.137.237.9 I get 9.237.137.193.in-addr.arpa domain
name pointer 193.137.237.9.IPLNet.local.
.local domain is often used internally for machines what use Active Directory at a LAN.
These type of internal host names should not
leaked by the DNS in Windows Server to the outside world.
73,
Bob VE3TOK
On 2017-10-12 06:58 PM, Pedro Ribeiro wrote:
Hello everyone,
I'm creating a gateway here, to be used to static and dynamic VPNs to Portuguese HAMs
trying to access the 44net.
I've noticed that after I've leaven the router a few days with the DNS relay open
(big mistake!), I was receiving a stream of dummy querys about a hundred per second.
I was able to block it in our (Lisbon Polytechnics) firewall (before ipip
de-encapsulation) with the next iptables rule:
# iptables -t raw -A PREROUTING -i eth0 -p ipencap -d 193.137.237.9 -m length --length 87
-m u32 --u32 "42 = 0x0035002f" -j DROP
Now I've disabled the gateway at the AMPR portal and I'll wait for them to calm
down.
I don't know if more tunnels are affected by this so I'm sharing the
information.
tcpdump output at the firewall:
10:24:57.864885 IP 169.228.34.84 >
193.137.237.9: IP 101.173.185.122.17596 > 44.158.128.1.53: 46623+ [1au] ANY?
activum.nu. (39) (ipip-proto-4)
10:24:57.864886 IP 169.228.34.84 > 193.137.237.9: IP 101.173.185.122.17596 >
44.158.128.1.53: 46623+ [1au] ANY? activum.nu. (39) (ipip-proto-4)
10:24:57.864888 IP 169.228.34.84 > 193.137.237.9: IP 101.173.185.122.17596 >
44.158.128.1.53: 46623+ [1au] ANY? activum.nu. (39) (ipip-proto-4)
10:24:57.864889 IP 169.228.34.84 > 193.137.237.9: IP 101.173.185.122.17596 >
44.158.128.1.53: 46623+ [1au] ANY? activum.nu. (39) (ipip-proto-4)
10:24:57.864929 IP 169.228.34.84 > 193.137.237.9: IP 101.173.185.122.17596 >
44.158.128.1.53: 46623+ [1au] ANY? activum.nu. (39) (ipip-proto-4)
10:24:57.864931 IP 169.228.34.84 > 193.137.237.9: IP 101.173.185.122.17596 >
44.158.128.1.53: 46623+ [1au] ANY? activum.nu. (39) (ipip-proto-4)
10:24:57.864933 IP 169.228.34.84 > 193.137.237.9: IP 101.173.185.122.17596 >
44.158.128.1.53: 46623+ [1au] ANY? activum.nu. (39) (ipip-proto-4)
10:24:57.864934 IP 169.228.34.84 > 193.137.237.9: IP 101.173.185.122.17596 >
44.158.128.1.53: 46623+ [1au] ANY? activum.nu. (39) (ipip-proto-4)
10:24:57.864936 IP 169.228.34.84 > 193.137.237.9: IP 101.173.185.122.17596 >
44.158.128.1.53: 46623+ [1au] ANY? activum.nu. (39) (ipip-proto-4)
10:24:57.864937 IP 169.228.34.84 > 193.137.237.9: IP 101.173.185.122.17596 >
44.158.128.1.53: 46623+ [1au] ANY? activum.nu. (39) (ipip-proto-4)
10:24:57.864938 IP 169.228.34.84 > 193.137.237.9: IP 101.173.185.122.17596 >
44.158.128.1.53: 46623+ [1au] ANY? activum.nu. (39) (ipip-proto-4)
10:24:57.864940 IP 169.228.34.84 > 193.137.237.9: IP 101.173.185.122.17596 >
44.158.128.1.53: 46623+ [1au] ANY? activum.nu. (39) (ipip-proto-4)
10:24:57.864941 IP 169.228.34.84 > 193.137.237.9: IP 101.173.185.122.17596 >
44.158.128.1.53: 46623+ [1au] ANY? activum.nu. (39) (ipip-proto-4)
10:24:57.864943 IP 169.228.34.84 > 193.137.237.9: IP 101.173.185.122.17596 >
44.158.128.1.53: 46623+ [1au] ANY? activum.nu. (39) (ipip-proto-4)
10:24:57.864944 IP 169.228.34.84 > 193.137.237.9: IP 101.173.185.122.17596 >
44.158.128.1.53: 46623+ [1au] ANY? activum.nu. (39) (ipip-proto-4)
10:24:57.864945 IP 169.228.34.84 > 193.137.237.9: IP 101.173.185.122.17596 >
44.158.128.1.53: 46623+ [1au] ANY? activum.nu. (39) (ipip-proto-4)
73!