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Questions tagged [networking]

Managing and using network connectivity on a unix system

3
votes
1answer
1k 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
143 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, ...
10
votes
3answers
31k 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
votes
1answer
4k 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 'myuser'"...
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 ...
2
votes
0answers
955 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
votes
1answer
462 views

Сan I configure FreeBSD to use DHCP or a static IP depending on the detected ssid?

I have a FreeBSD 8 machine which can use several wireless access points. I want it to use the first available network and automatically use DHCP or a static address as required (this should be ...
40
votes
2answers
38k views

how to check rx ring, max_backlog, and max_syn_backlog size

Quite often in the course of troubleshooting and tuning things I find myself thinking about the following Linux kernel settings: net.core.netdev_max_backlog net.ipv4.tcp_max_syn_backlog net.core....
1
vote
1answer
224 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 ...
2
votes
1answer
452 views

Multicast on local box

I have an application I need to interface with that listens to a multicast address. I'd like to be able to run a program I've written and have it interface with the other application by multicast ...
2
votes
1answer
5k 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
4k 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" ROUTE_GATEWAY[1]="192.1.1....
7
votes
4answers
10k views

Connecting to a network via another pc

What's a simplistic recipe to connect my PC to my WLAN through my laptop? I have one wireless network, one desktop that (for practical reasons) has no connection to the WLAN, and one laptop with ...
6
votes
1answer
4k 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
1k 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, ...
5
votes
1answer
4k 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
624 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. ...
0
votes
1answer
3k 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 ...
1
vote
2answers
4k views

Check the Existence of a Network Interface Card Redhat

I'm aware that I can use ethtool eth0|eth1|eth2 to check the existence of a NIC. But I wonder where the files are on the machine that contain information of an existing interface, as I need to use ...
2
votes
4answers
1k views

Is there a way to determine machine hostname without touching “/etc/hosts”?

Considering that I'm in a LAN that assigns IP addresses using DHCP (and that I'm not its administrator), how do I set things up such that when I ping <hostname> (instead of ping <IP address&...
5
votes
1answer
6k views

Changing Redhat Network Settings From DHCP to STATIC IP Via Configuration Files

In order to make the statically assigned IP work, I have already modified the file /etc/sysconfig/network-scripts/ifcfg-eth0 as follows: DEVICE=eth0 IPADDR=10.33.17.143 NETMASK=255.255.255.0 ...
2
votes
2answers
3k views

iscsi target to a folder of a mounted parition?

i'm thinking about installing and setting up iscsitarget on my Debian squeeze box. so far, the examples i saw on various Google searches and the debian wiki: http://wiki.debian.org/SAN/iSCSI/...
7
votes
1answer
7k views

Why is VirtualBox Bridged networking slow

When logged into the guest, data transfer (scp) from the host is very slow (<1MB/s). Is this expected? setup: VirtualBox host is Debian Unstable VirtualBox guest is Debian 6 (Squeeze) Bridged ...
1
vote
1answer
1k views

Only allow ssh/vpn on OpenWRT

If I don't want to use wireless encryption, but I still want security and I want to use sshuttle (on the clients, see: https://github.com/apenwarr/sshuttle/) for tunneling everything through an SSH ...
1
vote
1answer
3k views

Redhat Network Service Restart

I modified the /etc/sysconfig/network-scripts/ifcfg-eth0 file to set a static ip for my redhat. Then I tried to use command "service network restart" to make the change stick, however, it became stuck ...
51
votes
1answer
46k views

Why are the first 1024 ports restricted to the root user only?

This is more idle curiosity than anything else. A friend of mine asked me 'which port range is it that only root can use under Linux?' I told him 0-1024 were restricted. Then he asked my why it was so ...
4
votes
1answer
2k views

How to set a static IP in Ubuntu

How do I set my computer to have a static IP in Ubuntu 11.04? The only two lines in /etc/network/interfaces are: auto lo iface lo inet loopback I think usually when people do this they have a wired ...
5
votes
2answers
11k views

Firmware for wireless card on Ubuntu/Debian?

This is a follow up to my previous question about Debian support for Linksys Wusb600n. I have tried running the Ubunut/Xubuntu LiveCDs and the WiFi does not come up. The Gnome Network Manager menu ...
1
vote
1answer
548 views

Unexplained Log Cruft and Possible Dropped Packets on WPA2-Personal LAN

I've been receiving a LOT of log cruft ever since I installed my Linksys Rangeplus USB WUSB100v2 (using the rt2870sta community driver from the Linux kernel) and was wondering what it all meant. Many ...
11
votes
2answers
3k views

How do I hide/anonymise/defend a computer when on hostile networks?

I connect to a lot of open networks when I'm pootling around. I'm fairly careful to VPN home for anything important but that's not really my boggle. The laptop runs several services (nfs, dev http ...
6
votes
3answers
635 views

SpamAssassin Under Linux VPS

I am getting bald with this guys: On a Linux VPS (CentOS), I have setup a mail server (Exim+Dovecot+Clamav+SpamAssassin) but scanning mail for spam using SpamAssassin is proving to be a challenge. I ...
7
votes
2answers
15k views

How can I use Synergy when connected through different routers?

I use synergy to control my laptop from my desktop when I have my laptop docked at my workstation. Currently, I need to keep my laptop wired to the same router that my desktop is connected to in ...
4
votes
1answer
2k views

How can I configure fair bandwidth sharing between cgroups?

It's fairly easy to use tc with Stochastic Fairness Queueing (SFQ) to configure fair bandwidth sharing between flows, but an application can open multiple flows and get an unfair share of bandwidth. ...
2
votes
2answers
3k views

Reducing packet loss in tc rate limiting

I use this tc command to limit upload speed on an interface: tc qdisc add dev eth1 root tbf rate 2mbit burst 10kb latency 70ms peakrate 2.4mbit minburst 1540 But it results in heavy packet loss. If ...
6
votes
1answer
5k views

Two IP addresses assigned to the same machine?

I seem to be using two IP addresses on my PC. I use DHCP to get an IP address and then I statically set an IP address and activate it. ifconfig says that I am using the address given by DHCP but I am ...
3
votes
1answer
315 views

Set up network to share a printer connected to one particular machine on the network

How do I set up my Ubuntu machine to allow other computers to print to it? The set up is: All computers are connected to the network 1 dual Ubuntu/Windows 7 netbook 1 multibooting Debian/Ubuntu/...
-2
votes
1answer
288 views

How Can I “CAM attack” a switch/router?

Does someone has any script that can "CAM attack" a switch/router, so that it will act as a HUB? Are there any tools for it in the repositories?
2
votes
5answers
2k views

Remotely access Linux box with no IP address

I have two *nix boxes that are connected via ethernet. However I only have physical access to one of them. In working on the "remote" computer I messed up the ifcfg-eth0 file and instead of typing ...
3
votes
2answers
4k views

Setup WLAN interface on Debian

I am trying to configure wlan on my dockstar. I installed wireless-tools, zd1211-firmware and wpasupplicant. My /etc/network/interfaces file looks like this: auto lo eth0 iface lo inet loopback ...
2
votes
1answer
3k views

How to access shared locations on a windows machine from a linux machine via terminal?

I’ve setup a Virtual CentOS machine and set up a bridged network and static IP so that it can communicate with other Windows machines in the network. Currently, to access any shared directory, I ...
2
votes
1answer
2k views

Tool to monitor in and out data network traffic w graphs and detailed stats

Is there a tool, that can gather stats on network usage? Requirements: Generate HTML (or other format, convertible to HTML) Time line graphs for bandwidth usage, also which hosts use the most ...
0
votes
2answers
2k views

Understanding tcpdump output on a linux router

My router has an atm0 interface and a VLAN (atm0.1) interface, atm0.1 has the WAN IP address. When using tcpdump -i atm0, the packets captured are only outgoing packet (LAN to WAN). 05:34:19.504895 ...
3
votes
1answer
766 views

RealTek 8101E ethernet card or similar doesn't work on FreeBSD

I'm trying to install FreeBSD on my netbook using an usb sitck but I'm running into a major problem, my ethernet card doesn't work. ifconfig -a only returns me lo0 … but dmesg | grep re0 gives ...
2
votes
1answer
4k views

Unable to make outbound SNMP connections when IPTables is enabled

I have a bunch of windows servers configured with the windows SNMP agent. Each server has four IP addresses and SNMP listens on all of them. There is something very odd with my monitoring server (...
3
votes
1answer
687 views

Whole program name not visible in nethogs

I'm using the command sudo nethogs to watch network traffic. I have a problem in that the name of the program is too long (it doesn't fit in the PROGRAM column). I haven't found any nethogs ...
2
votes
1answer
620 views

Can't access HTTP contents, but HTTPS and SSH are fine

I'm having a weired issue wih my Fedora 14 recently. Many details involed. Let's start from this: I've been using Fedora 14 for months, and recent few days, offten I can't access Internet for hours. ...
6
votes
2answers
2k views

Configuring a vncserver so it's only accessible from my ssh tunnel

Since I use vnc through an ssh tunnel, is there any way I can block the open vnc port that the remote machine is listening on without it affecting my ability to use the ssh tunnel? Both machines are ...
2
votes
1answer
1k views

How to execute udhcpc as non-root

On a Linux machine, I am trying to run the udhcpc command as non-root. I am getting the error udhcpc: socket: Operation not permitted. Is there any way to execute udhcpc as a simple user in Linux?
3
votes
1answer
449 views

Neworking getting Disabled

I am using Fedora 13 and its working great. The only problem which I am facing is that the networking gets automatically disabled if I put my system on the "SUSPEND" mode for > 30mins. I am unable to ...
1
vote
3answers
814 views

How to set Internet Protocol properties using terminal?

When I set up a Virtual Machine with windows (using VMPlayer), I set the Network Connection properties from the VM settings from NAT to bridged. Then I proceed to set the following IP Properties in ...