Managing and using network connectivity on a unix system

learn more… | top users | synonyms (1)

-1
votes
1answer
108 views

Why DNS server changes when enabling another interface on machine

My system has 6 interfaces, a loopback, a Xen Bridge, and then 4 ethernet interfaces eth0-3. In this system, my DNS server assigned by DHCP on xenbr0 is 192.168.1.1. Initially eth1 is disabled and ...
-3
votes
1answer
2k views
1
vote
1answer
909 views

Wireless not showing a network in the scan results

I have a weird problem of connecting to a wireless network. I am connecting to a network named "C-202" with WPA-Personal. This network shows up in the scan results some time and won't show some time. ...
0
votes
2answers
459 views

What is the simplest method to redirect traffic using either a proxy or iptables?

I need to redirect all incoming traffic on port 7777 to a specific destination_ip:port. I have about 40 Litecoin (scrypt) mining rigs that I have to manually reconfigure each time I'd like to switch ...
1
vote
0answers
371 views

iptables server behind NAT accessible from outside as well as inside the nat

I have 2 machines with a KVM running on each machine - so two kvms with the below networking Host 1: 192.168.10.100 (eth2) 10.10.100.1 (virbr1) KVM 1 (NAT with Host 1): 10.10.100.128 (eth0 ...
1
vote
0answers
1k views

Port redirection on loopback with IP other than 127.0.0.1

I want to redirect port 80 on the loopback network interface so that accesses to that port actually go to port 8080. I tried using the following command, but it only works if the application is ...
2
votes
3answers
39k views

Method to check connectivity to other server

I want to check connectivity between 2 servers (i.e. if ssh will succeed). The main idea is to check the shortest way between server-a and server-b using a list of middle servers (for example if I'm ...
12
votes
4answers
49k views

How can I change the default “ens33” network device to old “eth0” on Fedora 19?

I've just installed a Fedora 19 on VMware workstation 9. The default network device is "ens33" instead of "eth0" on RHEL. The reason I have to use "eth0" is that the license component of one of our ...
1
vote
0answers
62 views

How to run a specific TCP client with a different IP?

My server has 3 ips. I use cronjob doing some api job. But this api has some limit: 100 calls/day. So how can i set a special ip for running some special script via cronjob? Thanks. 0,20,40 * * * * ...
0
votes
1answer
2k views

Ping to my own public IP results in host unreachable

First of all, I'm running a Manjaro 3.10 (Archlinux x64) install. I'm trying to make my No-IP configuration work. I have tried to ping my no-ip host and I recieve host unreachable ICMPs only. I was ...
3
votes
2answers
2k views

How do I fix iptables in ChromeOS?

Using the shell in chrosh in ChromeOS I followed some (apparently terrible) advice to flush my IP tables. using the command sudo iptables -F I am now unable to connect to the internet at all. All ...
1
vote
1answer
596 views

How can I allow applications to bind to any address in a subnet assigned to an interface?

I recently got a static IPv6 /56 prefix of my own from Freenet6, and am trying to allow applications to bind arbitrary addresses in the prefix. I modified the tunnel creation script that gogoc uses in ...
1
vote
1answer
4k views

Conntrack TCP Timeout for state stablished not working

Im using a private IP address and I want to keep alive SNAT entries in my Router (Gateway) for at least two hours (some windows apps of my network are using TCP keepalive set to 2 hours). Gateway is a ...
3
votes
1answer
252 views

How can I make sure that eth1 get its fe80 IPv6 address immediately on startup, even if it's not physically connected?

I'm working on an embedded-x86 Linux device that runs Debian (Linux 3.8.13). This device has two Ethernet ports, eth0 and eth1. If I boot up this device with only eth0 connected to a switch, and ssh ...
2
votes
1answer
959 views

Change IP remotely over ssh

I am using CentOS. I have a management server which has password-less ssh access to four other servers. I don't have physical access to these servers. In other words, I have to make all ...
2
votes
0answers
103 views

Ajax-y sites load sloooowly or not at all. [Ubuntu/Mint]

About two months ago I reinstalled Ubuntu onto my desktop machine. Since doing so I've had a lot of problems with certain websites and very slow or complete loading. It seems to be related to use of ...
0
votes
0answers
834 views

Help with Setting up network connection in Debian 7.5.0

I'm a beginner using Debian. I've just installed Debian 7.5.0 amd netinst. When I execute apt-get update I get errors like: Could not resolve 'http.debian.org' Thus I changed the mirrors several ...
1
vote
1answer
141 views

Parabola installation, “network is unreachable” despite working ping [closed]

I am trying to install Parabola(closely related to Arch Linux). As my wireless adapter does not work with linux due to some firmware issues, I have to use a wired connection. So, while a ping to www....
0
votes
1answer
260 views

Get a faster response for a ping

I noticed that the answer to my ping is slower in one debian machine that another. For the first one when i ping to 8.8.8.8: 64 bytes from 8.8.8.8: icmp_req=1 ttl=47 time=29.6 ms For the second ...
5
votes
1answer
2k views

LXC container to use “virtual” interface from host (namespace semantics)

So according to the documentation on the Ubuntu LXC documentation the following statement can be found at the time of this writing: A NIC can only exist in one namespace at a time, so a physical ...
1
vote
1answer
475 views

A question about wlan0 / eth0 and wireshark

I'm using wireshark to listen to packets on my own personal home network. I have my Desktop with Debian and Windows 7 running and my laptop is running the same setup; Debian and Windows 7. I ...
2
votes
1answer
70 views

Non-administrative network-related tools

I know there are tools to inspect packets (e.g. wireshark) or to simulate latency/packet loss (e.g. netem), but they all seem to require administrative permissions to inspect/modify packets. I'm ...
1
vote
0answers
41 views

I'm wondering about CUPS security. What can I do?

I run Debian Wheezy on a old Acer Aspire One ZG5 model netbook as a server. I have a printer shared to all my other systems and I'm worried about security. On the server I have IPtables set up to ...
7
votes
3answers
10k views

What are the benefits of using several IP addresses on a server?

With ifconfig, I am able to configure multiple IP addresses on a single network interface card. Why would I want to do that and how would I later utilize several addresses, e.g. how does software know ...
4
votes
1answer
3k views

bridge does not forwarding packets centos

I am using CentOS 6.5 64 and use xen to create a virtual machine (CentOS) ifconfig [root@CentOS ~]# ifconfig eth0 Link encap:Ethernet HWaddr 08:00:27:54:B3:FA inet6 addr: fe80::a00:...
0
votes
2answers
174 views

How to estimate server's network connection quality with traceroute?

I need to estimate network connectivity of various dedicated server hosting providers, e.g. how fast and uniform will my services perform when hosted there. I use traceroute command on my home ...
15
votes
2answers
18k views

How to make traceroute trace beyond 30 hops?

Some of the servers I use traceroute on, are more than 30 hops away. How do I make traceroute trace beyond 30 hops?
2
votes
0answers
327 views

sctp traffic generator

I'm looking for a free SCTP/TCAP traffic generator (specially for MAP, Camel and INAP protocols). I need to build some message flow scenario and generate load in order to test some application Thanks
0
votes
0answers
327 views

What is wrong with these iptables' rules?

The following is what I got after googling: iptables -A INPUT -i lo -j ACCEPT iptables -A OUTPUT -o lo -j ACCEPT #allow loopback access iptables -A OUTPUT -d 255.255.255.255 -j ACCEPT #make sure you ...
1
vote
2answers
125 views

simply change IP after installation on server minimal

I'm using CentOS 6.5 minimal. Is there any way to display a dialog to change the IP after login? In other words, some way of entering a command with a dialog to change the IP?
2
votes
1answer
122 views

Hosting on freeBSD

I already installed FreeBSD 10, Apache 2.4 and PHP 5.5. I also just bought a domain from GoDaddy, and I would like to setup a web-hosting in my server, in order to make my website to be reachable from ...
1
vote
0answers
18 views

Reverse proxy for OVZ containers

Is it possible to use a reverse proxy to channel all network traffic from one domain to a single container using the same IP for all the domains? The reverse proxy would have to read the domain and ...
4
votes
1answer
3k views

How does init determine which devices to modprobe?

I'm building a totally custom initramfs for a netbooting project and in the process learning a lot about it, but I'm a little puzzled by the loading of modules. I know modprobe can be used to load ...
0
votes
0answers
29 views

How to use networks default gateway dynamically? [duplicate]

I want to use specific interface for specific use from different different application. I am using Ethernet, Wi-Fi and 3G modem interfaces in my embedded Linux set-up. Now my set-up is up with ...
4
votes
1answer
7k views

TCP buffers keep filling up (Recv-Q full): named unresponsive

Using netstat -an, I set the message that the Recv-Q is full. It is filling up to the rmem_max: Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address ...
0
votes
1answer
141 views

Change network values from sysctl.conf

Can I change the value of those parameters (spoofprotect, syncookies, dynaddr_hack, notimestamps, nobroadcasticmpecho, ip_forward) from sysctl.conf file in systemd?
1
vote
0answers
168 views

How to find 3G signal strength when connection is already established by pppd? [duplicate]

I want signal strength information when pppd connection is already running. I am running pppd on embedded Linux environment and 3g modem manufactured Cinterion. I knew commands from which i am able ...
1
vote
2answers
4k views

How to forget/remove Mobile Broadband connection settings from Mint 14

I've been using Ubuntu for a while now and wanted to switch to Mint. I connected my mobile broadband dongle (Vodafone) for the first time like in Ubuntu it all went fine but subsequent connections ...
2
votes
1answer
494 views

SSH Setup - How will the router know my computer's ip?

I'm very new to the networking side of the house and am trying to set up SSH on my new Ubuntu machine. I have my DD-WRT router working with DDNS now and can log in to the router page -- but I'm not ...
1
vote
1answer
10k views

Enabling wired internet connection with dhcp during Arch Linux Installation? [duplicate]

From what I read, wired internet should work out of the box during the Arch installation. However, I'm having difficulties. The dhcpcd service is running, but it says: # systemctl status dhcpcd....
4
votes
1answer
2k views

Adding wlan0 to xenbr0

I'm setting up xen on debian to do some testing and having problems with the bridge. I would like to use wlan0 as the bridge, but can't seem to get this working. Currently I have tried this: # This ...
2
votes
0answers
37 views

Manually adding static ip not resolved after a while

Hi Unix/Linux community, I have a small problem with a device I am connecting to my laptop, running Debian Linux. While connected to a router on my wlan1 interface (using wicd, if that matters), I am ...
3
votes
3answers
15k views

How to reach a Vbox guest from host when using NAT networking

Using Fedora or Ubuntu for the host with firewalls turned off on each side (vbox guest&host), what do I have to do to reach the guest machine using a NAT interface just like it would be with a ...
2
votes
2answers
9k views

Redirect requests to my external IP/port to an internal IP/port?

I have a dedicated server running KVM virtualization with n public IP addresses dedicated to n-1 web-facing virtual machines. Now I'd like to set up some web-facing VM's that don't have a dedicated ...
2
votes
2answers
819 views

Lose network connectivity when bringing up second NIC

I currently have a CentOS 6.5 box with 4 NICs. eth0, eth2 and eth3 all come up fine, however when I bring eth1 up with an IP address, even on it's own, it causes complete network loss. If I remove ...
2
votes
1answer
134 views

Kernel optimiziations for ioctl AF_INET operations

Our server solution handles many tunnel operation requests (add/update/delete) using the ioctl interface, and the AF_INET address family socket. Aprox. numbers are 100 operations/minute with over 8k ...
3
votes
1answer
484 views

tcpdump command works only on local ip

I am trying to capture some IP packets in my personal LAN with tcpdump, through the command tcpdump -A -i eth0 'tcp and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0) ...
3
votes
2answers
299 views

How to configure Unison for real peer-to-peer?

I have a handful of devices, and am considering keeping them in sync with Unison. The devices are not running all the time, they are switched off a few hours per day, not necessarily at the same time....
1
vote
1answer
36 views

What is the meaning “MAC MISSMATCH”? [closed]

I have every day in the log the few lines start with: MAC MISSMATCH:IN=vlanXX OUT= MAC=ff:ff:ff:ff:ff:ff:bc:ae:c5:da:70:a6:08:00:45:00:00:4e SRC=xx.xx.xx.xx DST=xx.xx.255.255 LEN=78 TOS=0x00 PREC=...
1
vote
1answer
438 views

Create a VPN network between a live server and private networks

I have a VPS (Cent OS 6) on a live IP. I have several other machines (All linux, mostly Cent OS 6 and a few Android devices) sitting behind NATted ADSL Routers on several sites. I need to create a ...