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linux:administration:connectivity

Connectivity

DNS

Commands

  • lookup a server per DNS
    nslookup

Files

  • /etc/resolv.conf: DNS configuration
  • /etc/hosts: predefined hosts

LAN

Commands

  • show all configured interfaces and it's status
    ifconfig
  • show information about an Ethernet interface
    ethtool eth0

Files

  • /etc/sysconfig/network-scripts: interface up/down scripts (CentOS/RHEL)
  • /etc/network/if-up.d: interface up scripts (Ubuntu)
  • /sys/class/net: network interfaces files (info)

WLAN

Commands

  • WLAN configuration
    iwconfig
  • WLAN (detailed) info
    iwlist

DSL

Commands

  • discover PPPoE line
    pppoe-discovery

Files

  • /etc/ppp: PPP scripts

UMTS

Commands

  • bring up a 4G (UMTS) stick, means switch the flip-flop device from usb-storage to usb-serial (e.g. a O2/1&1 surfstick with ZTE MF627/628)
    usb_modeswitch

Samba

Commands

  • show the Samba tree
    smbtree
  • shows a list of available shares at a server
    smbclient -U <user> -L localhost
  • add a new user <user>
    smbpasswd -a <user>

Firewall

Add at least this rule (for example by use of the Uncomplicated Firewall)

sudo ufw allow proto udp from 192.168.178.0/24 port 137 to any

to allow NetBIOS name service to see your host. In case you only want to access shares on other hosts (and not allow access to your own) this seems to be enough.

If you want to participate as a full SMB/CIFS host (exporting shares for public access) then you probably need:

sudo ufw allow samba

or a solution according to Ask Ubuntu.

Files

  • /etc/samba/smb.conf: main Samba configuration file
  • /etc/samba/smbusers: translation of Samba user names to Linux names

Spamassassin

Files

  • /etc/mail/spamassassin/local.cf: main configuration file
  • ~/.spamassassin/user_prefs: user configuration file (see below)
# -*- mode: perl -*-
#
# Copyright (C) 2017 Ralf Hoppe <ralf.hoppe@ieee.org>
#
# SpamAssassin user preferences file.  See 'perldoc Mail::SpamAssassin::Conf'
# for details of what can be tweaked.
###########################################################################
 
# How many points before a mail is considered spam (default at the moment).
required_score		5
 
# Whitelist and blacklist addresses are now file-glob-style patterns, so
# "friend@somewhere.com", "*@isp.com", or "*.domain.net" will all work.
# whitelist_from	someone@somewhere.com
 
# Speakers of any language that uses non-English, accented characters may wish
# to uncomment the following lines.   They turn off rules that fire on
# misformatted messages generated by common mail apps in contravention of the
# email RFCs.
score SUBJ_ILLEGAL_CHARS      0
 
# score BAYES_00 -4
# score BAYES_05 -2
# score BAYES_95 6
# score BAYES_99 9
 
 
#### main performance related settings
 
# By default, SpamAssassin queries max. 3 (of 13 default) servers to attempt
# to check if DNS is working or not.  This is the main performance killer,
# especially in case a connection fails.  But turning DNS off has side effects
# of disabling of a lot of helpful network tests (only Bayes learning remains).
# If your ISP performs such checks for you then this should not be a problem.
dns_available no
 
# don't do DNS based RBL (Realtime blacklist) lookups
skip_rbl_checks 1
 
# By default, SpamAssassin checks the From: address for a valid MX two times,
# waiting 5 seconds each time. This consumes a lot of time - so i want this
# check only once.
check_mx_attempts 1
check_mx_delay 2
linux/administration/connectivity.txt · Last modified: 2018/06/28 07:11 by Ralf Hoppe