Managing and using network connectivity on a unix system

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2
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1answer
978 views

How to use tshark to do this task

I don't have any base knowledge about tshark, and it is hard to find any tutorial to help me with this. So now I have a pcap file which consists a lot of network flows; a time range; an ip addr; a ...
8
votes
2answers
2k views

minimal TCP MSS in Linux

The TCP MSS in Linux must be at least 88 (include/net/tcp.h): /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ #define TCP_MIN_MSS 88U My question is: where did they come up with ...
5
votes
1answer
6k views

Where are NetworkManager's WiFi settings stored?

I remember the days of playing with /etc/$WE/wpa_supplicant.conf to try and force a semi-secure network on a debian based system, but now on to xubuntu, I haven't needed to do any *.conf-ing in a ...
2
votes
1answer
5k views

Linux Mint 11 won't connect to Windows 7 Wireless Ad Hoc

I apologise if this question has been asked before, but I am not exactly sure what I should be looking for, hence my reason for posting a new question. I am a newbie to Linux and have been using ...
4
votes
1answer
1k views

How to create an ad-hoc connection?

I need to make an adhoc connection on Archlinux (netbook used as a wifi repeater), I was using this tutorial to do it on Ubuntu : At the terminal install execute sudo apt-get install dnsmasq-base ...
2
votes
1answer
114 views

ifconfig shows an IP out of the lan range

I have set router IP to 192.168.112.20 and starting IP address to 192.168.112.25. But when I run ifconfig command it shows the following IPs: inet addr: 192.168.174.12 Bcast 192.168.174.255 ...
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vote
2answers
3k views

How can I debug a problem with my network connection?

On one of my computers with Xubuntu 10.04 there is a problem with the network connection. How can I debug it? I tried the cable on my laptop (running the same operating system) and it worked, so ...
1
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2answers
662 views

How to keep overwriting the contents of a file instead of appending to it

How do I clear the contents of a file before writing to it? For example: echo one > filename.tmp # filename.tmp now contains "one" echo two > filename.tmp # filename.tmp should now contain ...
0
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1answer
2k views

How to do “netcat” relays properly so that I have more control?

How to use the netcat to have relays? Like following I tried but not working: cd /tmp mknod backpipe p nc -l -p 7007 0<backpipe | nc 192.168.1.101 9001 | tee backpipe I want to receive data on ...
4
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3answers
2k views

How to get list of computers similar to what is shown under “Network” in Windows

In Windows 7 when I click on Network I get a list of computers with the same workgroup of mine. But in Fedora when I click on Network I just get a single item Windows Network and I can't see the ...
4
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4answers
7k views

Make some virtual MAC address

I want to make some virtual MAC addresses for my network adapter or wireless adapter, so I can connect to network with more than one IP address from one computer or laptop. How can I do it? (I know ...
2
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2answers
2k views

What do the three values mean on network monitoring tools

Often in network monitoring tools there are three values for one measure. Ex rx: 2.0 kb/s 40 kb/s 10 kb/s Are these similar to how cpu load works, they are taken at different length time spans. ...
3
votes
1answer
478 views

Running a pbk file in Linux

To connect to my university's network, they provided me with a .pbk file. The file is made for windows of course and I have no idea how to use it in Fedora (I'm using Fedora 15)
1
vote
2answers
133 views

Use Linux to backup a MSWindows network?

Is it possible to use a Linux machine to backup everything on a Windows network? I would like to backup MS databases and also drives, so if a database record needs restoring, it can be done easily, ...
5
votes
3answers
10k views

How does traceroute resolve names?

While writing a script, I wanted to reference a machine by the computer name that I gave it (e.g. "selenium-rc"). I could not ping it using "selenium-rc", so I tried the following commands to see if ...
4
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3answers
5k views

Source code of netstat

Can I view the source code of netstat on my Linux machine?
4
votes
3answers
2k views

IPTables and transparent proxies

I have set up a local, transparent TCP proxy on localhost. I want to redirect ALL TCP traffic to this proxy, so it can handle it and nothing "leaks out," circumventing the proxy. I need to use ...
2
votes
1answer
205 views

Testing intranet network

This is probably a question already discussed here and there. I'd like to try to gathering here all the information. Suppose I'm on a machine connected to a network. This network has access to the ...
3
votes
3answers
3k views

How do I deploy Firefox Bookmarks for all Users in Network?

I have a bash-script for installing Firefox which is downloaded and executed from every client workstation in the network. The script is on the server and all workstations are running Ubuntu. Now I ...
11
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3answers
24k views

Output traffic on different interfaces based on destination port

My question is basically the same as Only allow certain outbound traffic on certain interfaces. I have two interfaces eth1 (10.0.0.2) and wlan0 (192.168.0.2). My default route is for eth1. Let's say ...
3
votes
5answers
1k views

How can I test whether connection to the given host/port is established in Bash?

Currently I'm using netstat for this: if netstat -an | grep ESTABLISHED | grep $address:$port > /dev/null; then # command fi Is there a more elegant solution?
23
votes
4answers
16k views

How to speed up X over SSH on a slow network connection?

Are there any specific recommendations on speeding up X applications over ssh on a slow network connection? In this specific case, I am accessing a server located in west coast from a laptop in east ...
0
votes
1answer
471 views

Private vlan concept (rfc 5517)

I'm learing vlan concept and came around private vlan rfc. I think that i understand the reason and implication of isolated domain, but i'm not sure that i understand the community domain. ...
3
votes
3answers
5k views

How should I determine the current network utilization?

I want to display the current network utilization (bandwidth usage) of one interface of a Debian box on a website. It is not supposed to be very elaborate or precise, just a simple number such as "52 ...
13
votes
3answers
12k views

Does mount always require root privileges?

I was under the impression that any sort of call to mount requires root privileges. But recently I was told "You should instead create appropriate entries in /etc/fstab so that the filesystems can be ...
4
votes
1answer
3k views

How do I recover/kill an SSH session after losing connection?

I lost my connection while I was logged via SSH into my university server. Classic. Now I can't log in since the session appears to be still running and I get the error "Too many logins for ...
0
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2answers
1k views

Dropbox doesn't connect properly on boot

I'm having a problem with Dropbox (version 1.1.35). When I first boot it takes some time before Network Manager connects to the WLAN. Then I see the Dropbox icon in the task list, claiming to be ...
1
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1answer
1k views

New SL6 system: No hostname?

This is in regards to Scientific Linux 6.1 system, but should also apply to CentOS 6.1 & RHEL 6.1. I am setting up a new Scientific Linux 6.1 system, using kickstart and DHCP (via xCAT). This ...
1
vote
1answer
2k views

What does this error mean: “igmp[1435]: setsockopt IP_MSFILTER”?

My network connection is pretty crappy today so I looked at my router (TP-LINK TD-W8950ND) logs and can see these entries a few times every minute: Date/Time Facility Severity Message Sep 7 ...
5
votes
4answers
2k views

How can I send spoofed packets in Linux

In order to test a firewall, I want to send malformed packets to its interface, regardless of my routing table. Is there a way to ask linux "send this exact tcp package, to this MAC address, ...
2
votes
2answers
339 views

UDP multicasting broken after kernel update

I've got an embedded system which is running a stripped down Gentoo userland with a manually build kernel. The system acquires data from a PCI card and sends it out to an UDP multicast group. All ...
2
votes
0answers
457 views

Why are packets not moving forward? [closed]

I have a server with forwarding turned on. I placed an iptables LOG target in the PREROUTING, INPUT, and FORWARD chains of the mangle table. I can see the LOG messages from PREROUTING, but not INPUT ...
2
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1answer
121 views

Reporting Network and Vital Statistics and writing to db and image

I am looking for a versatile tool that can write either to a MySQL db, or possibly simply even just write some image charts (that i can display on a PHP dashboard) to monitor my network health. Is ...
-1
votes
4answers
853 views

How can I configure IP address from class E on Linux?

I would like to configure an IP address from class E, for example 241.0.0.2. Currently Linux (Linux-2.6.21.7-hrt1) returns the following answer: ifconfig: SIOCSIFADDR: Invalid argument Is there a ...
4
votes
1answer
299 views

Reverse ip lookup

I was wondering if it is somehow possible to lookup the ip of a machine I ssh'd into from. This is the scenario, I'm at home, I've VPN'd into a server that I ssh into constantly in the office but now ...
1
vote
1answer
174 views

How to “set” this home network mesh up

I don't know much about networking security other than keeping unused ports closed is good. This is what I'm trying to accomplish: I need to be able to keep my server (the dotted line) with limited ...
4
votes
3answers
793 views

Access point (with hostapd) on the same interface as the network/gateway?

I wonder if it should be possible to have an wireless access point using hostapd (as described in Set up an access point) on the same interface that connects to a wireless network for internet. I ...
11
votes
5answers
8k views

How to recover a shell after a disconnection

Am doing some work on a remote centos 5.6 machine and my network keeps dropping. Is there a way i can recover my hung sessions after i reconnect? EDIT: am doing some updating and installing with yum ...
4
votes
1answer
944 views

Can I spoof the MAC address in Android?

Is it possible to spoof the MAC address of the wireless interface using wpa_supplicant.conf in Android when I connect as a client to an access point? Edit Unfortunately, Android doesn't support ...
2
votes
1answer
3k views

Why does iptables still block my samba?

I'm currently fighting with iptables and samba. I read that samba needs ports 137-139 and 445 open on both tcp and udp. Here is the relevant part of my iptables config ... # forward valid incoming ...
2
votes
1answer
2k views

Static routes in HP-UX

I need to set static route in HP-UX. I edited /etc/rc.config.d/netconf file and added new entry for my route: ROUTE_DESTINATION[1]="10.105.2.0" ROUTE_MASK[1]="255.255.255.0" ...
3
votes
2answers
147 views

How can I print out information about a Wireless Access Point in range?

How can I print out information about a Wireless Access Point in range? Can I for example get the MAC address?
6
votes
1answer
3k views

LXC container network/routing issues

I have been experimenting with LXC virtualisation in order to run virtual machines on a dedicated server, but am having trouble setting up the networking properly. I am using veth bridged networking, ...
2
votes
1answer
665 views

Is it possible to use Internet Connection Sharing with DHCP?

I know it is possible to share an internet connection with another pc using ip-forwarding and masquerade. Is it possible to set up the sharing computer as a DHCP server, so the settings (ip, gateway, ...
12
votes
1answer
7k views

Buffer size for capturing packets in kernel space?

Going through the man page of tcpdump, it seems kernel can drop the packets if the buffer is full. I was wondering if: that size is configurable and/or where can I see the size for my distro? From ...
3
votes
2answers
904 views

Which user group can use the 'tap' net device?

I use the 'tap' net device with KVM to get my vm connect to the Internet. But I have to be root, or use 'sudo', which is inconvenient. I think I can put my user account into some group so I can access ...
3
votes
1answer
1k views

Is it possible to capture all network traffic using tcpdump?

I have 3 computers on the same sub-net. Computer A and B are communicating with each other (ping, telnet, etc.). I'd like to see the packets between A and B on computer C. Is it possible to do this ...
1
vote
1answer
425 views

netcat throughput low but iperf high [closed]

I was testing the throughput between two pcs connected on the same router: one with 100mbps lan, the other with 54mbps wifi. I tested both netcat and iperf and the throughtput I get is only 2.6mb/s. ...
3
votes
1answer
1k views

Mounting a network drive automatically when needed and unmount it again after some time with inactivity

I have a somewhat old NAS hosting my music collection. It is not capable of running a DAAP media server so I have mounted the music folder on my Sheevaplug (a tiny headless server running Debian) ...
0
votes
1answer
1k views

How to configure DUAL-WAN on a Linux/*BSD machine?

I have two internet connections. The cables from the two ISP's (dhcp; 1-10/10 Mbit; 2-20/20Mbit connection) are on two interfaces: eth0 and eth1. On eth3 there is a Gbit switch and on the switch there ...