Mailinglist Archive: opensuse-security (670 mails)

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Re: [suse-security] Antwort: Re: [suse-security] IPTables ... Logging
  • From: "Erwin Zierler - stubainet.at" <erwin.zierler@xxxxxxxxxxxx>
  • Date: Wed, 28 Nov 2001 17:10:22 +0100
  • Message-id: <3C050C6E.3090905@xxxxxxxxxxxx>
Hi,
as someone else already suggested: RTFM (read the fu**ing manual).
This is not an arrogant statement but a totally normal advice - it's
been this way since the early days of the internet (as I remember it).

You really need to read about networking, protocols and services if
you are serious about firewalls and security in general. Without a basic
knowledge it will be very frustrating to try and get things working.

To answer your question: it is a good idea to block netbios traffic
(137-139 TCP and UDP) trying to access anything else but your local LAN.

Erwin

---
BLeonhardt@xxxxxxxxxxx wrote:

Ok,

so thank's for all your answers ... it's working now ...

... but today something strange is happend ...

the host tried to make a connection to an unknown IP on port 137 ( UDP )
... why that ?
... usually Port 137 ( UDP ) is :

netbios-ns 137/tcp # NETBIOS Name Service
netbios-ns 137/udp # NETBIOS Name Service

... here the log-entry :

Nov 28 12:26:22 linux-box kernel: OPEN: 192.168.10.60 -> 213.6.48.154 UDP,
port:137 -> 137

... anybody an idea ??? should I deny any connections from host to internet
on this port ???

Mit freundlichen Grüßen
Bruno Leonhardt

CLP Domino R5 Systemadministrator
________________________________________________________________________________________________________

AnalyTek Systemhaus
Hospitalstr. 2a

D-65589 Hadamar

Tel.: 06433/81403-15
Fax : 06433/81403-40





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