12 Oct
2017
12 Oct
'17
7:25 p.m.
It looks like they are trying to use your host as a DNS server. I have
found it best to block the port (53)
On Thu, Oct 12, 2017 at 3:58 PM, Pedro Ribeiro <ct7abp(a)gmail.com> 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
--
------------------------------
John D. Hays
K7VE
<http://k7ve.org/blog> <http://twitter.com/#!/john_hays>
<http://www.facebook.com/john.d.hays>
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!
--
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Callsign: CT7ABP
QRA: Pedro Ribeiro
GRID Locator: IM58mr
QTH: São Francisco, Alcochete, Portugal
NET: http://www.qrz.com/db/CT7ABP
CT7ABP is also home station of CR7AJI Diogo
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