Tagged Questions
-1
votes
1answer
39 views
Recognizing when my machine has the IP of someone else [closed]
From times to times my computer is very slow in accessing internet or going to the network. Few colleagues of mine suggested that my machine might have the same IP of another one and this would cause ...
0
votes
0answers
15 views
Internet not working after configuring server for DNS with dyndns [migrated]
Objective to be achieved: To access the server using a name server.xyz.com.
I've a domain xyz.com and a server behind a router. Also, I've configured my server with dyndns. On executing the ...
0
votes
0answers
66 views
One way ping on an embedded Linux system
I'm facing a networking issue with an embedded Linux system in a private network. We have a network that consists of a few tens of servers connected through a switch with one of the servers acting as ...
0
votes
2answers
26 views
Prevent internet access except for one server?
I want to see if the HTTP proxy support for an application is working correctly. In order to check this I have installed a Ubuntu VirtualBox on my Mac laptop and I want to configure the virtual ...
1
vote
0answers
28 views
Receive errors counter in /proc/pid/net/dev
Can anyone explain what gets reported in /proc/pid/net/dev in the receive "errs" column:
$ cat /proc/1372/net/dev
Inter-| Receive | Transmit
face ...
-2
votes
1answer
25 views
Connecting vmware on two computers [closed]
I have a switch and 2 computers, each one has vmware with a running centos 5.8 on.
what i am trying to do is ping centos2 from centos 1 through the switch(10\100).
please help.
1
vote
0answers
31 views
How can I set ntop not to shorten host names?
With most screens in ntop, there is a list of hosts. Unfortunately, in almost every one, the host name is shorted, for some reason. When the host names follow the company standard, this results in the ...
3
votes
2answers
100 views
Mysterious “fragmentation required” rejections from gateway VM
I've been troubleshooting a severe WAN speed issue. I fixed it, but for the benefit of others:
Via WireShark, logging, and simplifying the config I narrowed it down to some strange behaviour from a ...
0
votes
0answers
14 views
Broadcast across a VDE switch
I created a simple VDE Switch as per:
http://stackoverflow.com/questions/2082722/how-do-i-create-virtual-ethernet-devices-in-linux
To paraphrase that question, the setup is:
sudo vde_switch -tap ...
0
votes
0answers
42 views
Always get “SIOCADDRT: File exists” when restarting networking on ubuntu
I have a problem very similar to getting error "SIOCADDRT: File exists" when trying to restart network on ubuntu, but it is not a duplicate for reasons explained below. My ...
0
votes
0answers
54 views
Openvswitch configuration with Ubuntu VM
I have a Windows 7 PC as host.The network details of my Windows PC are as follows.
IP ADDRESS - 192.168.1.70
DEFAULT GATEWAY - 192.168.1.254
I have installed Virtual Box ...
1
vote
1answer
51 views
How do I receive traffic to the public IP of an additional ENI on EC2 Ubuntu?
I've added an additional network interface with elastic public and private ips. In ubuntu I can see the interface getting a local IP from DHCP, but I cannot ssh to the additional public IP.
I'm ...
1
vote
1answer
48 views
Is it insecure to use the following iptable rule for NAT?
I want to setup a VPN server for personal use, so I follow the blog article [1], and it work like a charm.
The only thing I am wondering is if the iptable's rule secure, e.g.
iptables -t nat -A ...
0
votes
1answer
36 views
How can I find the cause of an unknown connection showing in iftop?
I have connections like this showing frequently in iftop:
12.15.127.75.host.nwnx.net => 121.61.153.172 480b 160b 40b
I have no idea ...
11
votes
1answer
485 views
arp-requests cannot be seen by specific nodes
I create an open ad-hoc wlan by using iwconfig (I have the same issue with wpa_supplicant as well). there are 4 nodes on the network as seen on the figure below. The nodes run ubuntu 12.04 and debian ...
1
vote
1answer
64 views
Why there are always 10% of loss when testing with mtr command?
For example, if I run this command against example.com, with mtr command, I always get 10% of loss, no matter how many time I run, why exactly is 10%?
mtr --report 192.0.43.10
HOST: localhost Loss% ...
1
vote
1answer
109 views
Multiple macbooks can't connect to company web server
We're having a very strange problem where 2 macbooks running osx 10.8.2 can't connect to our public facing server on any port.
Attempting to ssh or navigate to the web server fails, but every other ...
0
votes
4answers
541 views
IPv6 only works after pinging the default gateway.
We now have 2013 and I thought it is long overdue to activate IPv6 on my server. But unfortunately, I ran in some problems. To be honest I only have litte experience with IPv6 So I hope you can help ...
0
votes
1answer
43 views
Tracking data sent to remote host over time?
What is a a good way to track over time the amount of data transferred from my Linux server to another host on the internet? https and imaps only
1
vote
1answer
130 views
Setup Network with two ISP
Currently I have a network with 1 ISP, a router/modem, Gigabyte Switch and a server.
All the clients PC are automatically assign IP from DHCP server from a Router/Modem A.
Server A have a fixed IP ...
0
votes
0answers
111 views
keepalived does not release virtual IP
I have two servers to float a single Virtual IP (10.10.10.101)
Server1 and Server2
In the Server1, syslog
VRRP_Instance(VI_1) Received higher prio advert
VRRP_Instance(VI_1) Entering BACKUP STATE
...
2
votes
1answer
90 views
Bandwidth fluctuations while running java server
We are running a distributed system of java servers (os: linux) doing lot of computation with communication over TCP. While our traffic pattern in not bursty, on some machines we see a fluctuation in ...
1
vote
1answer
60 views
Ubuntu Second Wan Interface Card
I configured 3 network card.
one of them is LAN card and others are Wan network card.
eth0 Link encap:Ethernet HWaddr 00:50:56:00:30:da
inet addr:5.x.x.1 Bcast:5.x.x.3 ...
-1
votes
1answer
91 views
How to put an entire subnetwork behind a VPN [closed]
I am looking for information on how to get started (tutorials, pointers, etc.) on how to setup a subnetwork that would get behind a VPN connection "transparently".
The over setup is simple:
- 1 cable ...
0
votes
2answers
161 views
How do I configure dd-wrt to forward IP Protocol ID 50 & 51 traffic to an internal machine?
Please note, I'm not talking about TCP or UDP traffic. Rather IP traffic with the protocol ids of 50 and 51.
The point of this being that I can then pass IPsec traffic thru to the internal machine ...
2
votes
1answer
99 views
Linux router: bandwidth of client
I am trying to build a linux router (captive portal) with a local RADIUS server for authentication.
I want to log the bandwidth being used by each client on my network. I want to associate bandwidth ...
1
vote
1answer
161 views
Setting up bridging for Qemu and routing for OpenVZ (venet) with multiple subnets on Debian Linux
So i've been searching the past couple days trying to figure out the best way to achieve this but still can't get it figured out.
I have a debian server setup running Proxmox to host OpenVZ and Qemu ...
4
votes
1answer
165 views
RHEL/CENTOS6 Interface naming and IP assignment for rotating MACs
Background:
I am creating an RHEL6 OS disk image that will potentially be passed around to many different computers with identical hardware (except for serial numbers such as MACs). The image is ...
0
votes
1answer
71 views
Open Stack Installation - single server
I have managed to set up openstack on a single machine, everything appears to work with exception to being able to ssh.
I can ssh to the instance from the host box, which has a public ip. However as ...
0
votes
1answer
415 views
bridging two network interfaces in ubuntu linux 12.10 AND being able to access it from that machine
Ok, i have about had it but heres the deal.
I have 7 total machines connected like this:
[5 workstations]<--->ServerPC<---->MAINPC<---->router
FYI, dont worry about the workstations they ...
0
votes
1answer
47 views
Outbound traffic from domU shows dom0 IP address
I am having a problem with Xen where all outbound traffic from domU's are showing up as if it was coming from the dom0. Traffic passes both ways without a problem. I do not have NAT enabled. I am ...
-3
votes
1answer
269 views
Changing the default gateway address in Centos
I have a a Centos PC with 2 IP addresses. One of them is because of a back to back connection with another PC, so both run on different subnets. The eth0 has the 192.xx.xx.xxx address and eth2 has ...
0
votes
0answers
204 views
Unable to start interface - RTNETLINK : File exists
I can't get my eth1 interface to either go down or go up
My /etc/network/interfaces file :
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network ...
1
vote
1answer
170 views
Meaning of number inside iptable rules' brackets? [duplicate]
Possible Duplicate:
Don’t understand [0:0] iptable syntax
E.g. The command iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 8080, lead to the configs
*nat
:PREROUTING ...
1
vote
2answers
170 views
Network no longer works after replacing components on Ubuntu
The motherboard of my server (Ubuntu 8.04) died, so I replaced the motherboard, CPU, and RAM. Now I cannot get the server working on the network as it was configured.
The network is configured ...
1
vote
0answers
71 views
Standards for evaluation of quality of Internet access services [closed]
On the site of Pittsburgh Supercomputing Center ( http://www.psc.edu/index.php/hpn-ssh ) shows detailed procedures for system tuning under various operating systems to provide a high bandwidth ...
1
vote
0answers
95 views
Peer to peer ipsec tunnel - virtual network interface
I'm trying to create an IPSEC tunnel between two machines (not between two networks). Using ipsec-tools, TUNNEL mode.
I think I can cope with all those add and spdadd, but how to create a virtual ...
2
votes
2answers
132 views
Server sending out packets bigger then MTU
I have a server that I am transferring data off of. We were having some problems that were traced back to the fact that the server is sending out jumbo size frames despite the fact that ifconfig is ...
1
vote
1answer
98 views
IPv6-“GARP”/ Gratuitous ND
I am maintaining an office network with several VLANs.
These VLANs are terminated by a redundant pair of Linux boxes as router.
Between those I am running VRRP (with keepalived).
On failure I am ...
1
vote
3answers
167 views
iptables blank after reboot
We've started encountering an issue with iptables on our RHEL 6.3 systems in that after a reboot, when the service starts, the rules are not loaded. We get the empty ruleset:
[msnyder@matt-test ~]$ ...
4
votes
1answer
88 views
ping request not forwarded in one direction
Edit: I solved my issue just as I was finishing this insanely long post. I had simply not enable ping reply in my windows firewall which is why I could not ping a computer on network 0 from network 1 ...
1
vote
0answers
61 views
What is the meaning of the QUEUE in arptables
I use the nfqueue target of iptables in order to get packet to the nfqueue and do some business rules on them.
iptables -A INPUT -p tcp -j NFQUEUE --queue-num 0
I need to do the same on arp reply ...
-1
votes
4answers
98 views
Is it possible to display realtime network utilization without third part tools in Linux [duplicate]
Possible Duplicate:
Is there a linux terminal command that lets you see the amount of data coming in to your tcp connections in real time?
I want to able to display realtime (or near ...
1
vote
1answer
286 views
Service networking restart not working on ubuntu
This one has been cracking my head for quite a bit and I can't seem to find a decent answer for it, hoping you guys can shed some light to it...
# Loopback interface:
auto lo
iface lo inet loopback
...
2
votes
2answers
218 views
Server becomes unreachable and comes back up on its own (most likely a network issue)
I'm having a strange problem with a server I have sitting at my workplace (it's behind a NAT, if that's important). The issue is that at some times, it becomes unreachable and then comes back up ...
-1
votes
2answers
138 views
Reaching a server behind behind a Double NAT [closed]
I live in an apartment complex that manages my Internet. It looks like they have a router for the complex, and then I have a router in my apartment that covers my local network (an Airport Express) ...
1
vote
1answer
68 views
Route Traffic Through Linux Server With Two Devices
Here is my current setup (all servers are Ubuntu Server Edition 12.04):
Server 0 has two devices, eth0 and eth1. eth0 is connected to the wall (the internet), and eth1 is connected to a switch. ...
0
votes
0answers
255 views
Linux vpnc connection “lost” after period of time
I have OpenSuSE 11.4 and Slackware 13.37. On both machines there is vpnc client. If I start vpnc connection is successfull, I can start work. After period of time (if there is no activity this period ...
-1
votes
1answer
274 views
How to set up VirtualBox Guest as Server on Different Subnets? [closed]
First, my server only has two public IP addresses.
eth1 188.138.124.244 netmask 255.255.255.192
eth1:0 85.25.110.198 netmask 255.255.255.192
default gateway: 188.138.124.193
How can I set up ...
2
votes
1answer
1k views
How to troubleshoot latency between 2 linux hosts
The latency between 2 linux hosts is about .23ms. They are connected by one switch. Ping & Wireshark confirm the latency number.
But, i dont have any visibility into what is causing this latency. ...
