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Re: [OT] after portscan



On Tue, Sep 05, 2000 at 11:47:32AM +0200, ISM Kolemanov, Ivan wrote:
> hi again helpful people in misc,
> 
> Which steps I have to do in such a "standard" case:
> 
> Sep  4 21:31:43 211.34.121.57:2429 -> x.y.z.xy0:21 SYN **S*****
> ...
> Sep  4 21:31:43 211.34.121.57:2443 -> x.y.z.254:21 SYN **S*****
> 
> OK, in this case I'm not really afraid, it looks like smb
> just started an ftp probe in a big range of IPs
> and I have no ftp server running, and feel good with
> OpenBSD system + Snort as IDS
> but what I have to do in such a situations,
> probably I have to contact his ISP?

honestly i dunno, and would like to see comments about some common
practice.

> and how to define it?

i'd do "dig -x 211.34.121.57 soa", that results in:

; <<>> DiG 2.2 <<>> -x soa 
;; res options: init recurs defnam dnsrch
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 36748
;; flags: qr rd ra; Ques: 1, Ans: 0, Auth: 1, Addit: 0
;; QUESTIONS:
;;      57.121.34.211.in-addr.arpa, type = SOA, class = IN

;; AUTHORITY RECORDS:
34.211.in-addr.arpa.    10222   SOA     ns.krnic.net. domain.krnic.net. (
                        1999122121      ; serial
                        21600   ; refresh (6 hours)
                        900     ; retry (15 mins)
                        604800  ; expire (7 days)
                        43200 ) ; minimum (12 hours)

;; Total query time: 26 msec
;; FROM: comrade to SERVER: default -- xxx.xxx.xxx.xxx
;; WHEN: Tue Sep  5 12:07:39 2000
;; MSG SIZE  sent: 44  rcvd: 118

so it seems krnic.net (korean ISP?) is authoritative for that range
of IP addresses. abuse@krnic.net is the way to go?

> traceroute 211.34.121.57
> ...
> 18  teleglobe.ny2-gw.customer.ALTER.NET (157.130.4.166)  372.59 ms
> teleglobe-gw.customer.alter.net (157.130.5.218)  321.318 ms  563.356 ms
> 19  if-0-0.core1.NewYork.Teleglobe.net (207.45.221.97)  258.22 ms  275.539
> ms *
> 20  * if-3-0.core1.PaloAlto.Teleglobe.net (207.45.222.177)  319.379 ms
> 419.846 ms
> 21  if-3-0.core1.Seattle.Teleglobe.net (207.45.223.74)  336.904 ms  348.585
> ms  434.562 ms
> 22  * if-3-0.core1.Burnaby.Teleglobe.net (207.45.222.86)  431.677 ms
> 492.954 ms
> 23  if-1-0.core2.LakeCowichan.Teleglobe.net (207.45.223.174)  356.243 ms
> 504.686 ms  480.54 ms
> 24  if-11-0-0.bb3.LakeCowichan.Teleglobe.net (207.45.222.110)  535.302 ms *
> 257.395 ms
> 25  ix-4-0-0.bb3.LakeCowichan.Teleglobe.net (207.45.211.102)  1170.856 ms
> 1160.818 ms  1220.668 ms
> 26  * 202.30.90.5 (202.30.90.5)  1431.386 ms  1097.884 ms
> 27  202.30.90.9 (202.30.90.9)  993.712 ms  1041.541 ms  1118.923 ms
> 28  202.30.90.1 (202.30.90.1)  1178.533 ms  1063.533 ms  1159.69 ms
> 29  202.30.94.6 (202.30.94.6)  1402.126 ms  999.289 ms  1194.884 ms
> 30  210.104.13.117 (210.104.13.117)  971.940 ms 202.30.94.130
> (202.30.94.130)  1092.677 ms *
> 31  210.100.139.158 (210.100.139.158)  1040.280 ms *  1090.352 ms
> 32  210.95.28.126 (210.95.28.126)  1199.438 ms 210.104.217.118
> (210.104.217.118)  978.729 ms 210.104.217.114 (210.104.217.114)  1078.909 ms
> 33  RFC1918-Host (192.168.137.158)  952.505 ms  1304.449 ms  1091.662 ms
> 34  211.34.121.57 (211.34.121.57)  1043.118 ms  1170.166 ms  1038.541 ms
> 
> can anybody give me an idea about "33"

33 is the host with LAN IP address (as defined with RFC1918), which
are:

10.0.0.0/8
172.16.0.0/12
192.168.0.0/16

it's usual practice to give LAN addresses to routers, this doesn't
affect connections they serve. IMHO it's silly, that its packets
aren't filtered and go to the world...

-- 
Denis A. Doroshenko
Omnitel Ltd., Sevcenkos 25, Vilnius 2600, Lithuania
mailto:d.doroshenko@omnitel.net