2
votes
1answer
150 views

Host doesn't send ACK-SYN packets for transparent proxy

I am setting up a transparent proxy using haproxy, the setup works without the 'source 0.0.0.0 usesrc client' line. When I add that line in, the endpoint is called from the original client's ip ...
-1
votes
1answer
42 views

Firewall Connections fail to open under load

Problem : During High load , our applications are encountering errors : java.net.connection Time out. After some investigation , we found out that it was Firewall the root cause, but still don't know ...
1
vote
1answer
179 views

Do keepalives to socket connections exist?

Pre briefing: Although my question is broad on purpose, I am dealing with nginx connecting to php-fpm (fcgi), which is served via a local socket (/tmp/somesocket.socket). Nginx has a setting to ...
1
vote
2answers
866 views

Linux server resend SYN ACK

I am troubleshooting a connection timeout problem between two Linux boxes, where it seems the ACK to SYN-ACK was lost on the server's stack. The tcpdump is done on the server side. The client got ...
2
votes
3answers
2k views

Squid TPROXY connection fails on specific sites?

When squid setup as TPROXY, returns ERR_CONNECT_FAIL on some sites . The server which squid runs on it is able to open those sites by lynx, wget, curl etc . Even if we manually set proxy in browser ...
0
votes
1answer
279 views

Way to do basic WAN optimization between two Linux servers that splits single connection into multiple parallel ones? [closed]

There are utilities on Linux that allow you to work around WAN conditions which cause you to not be able to utilize your full bandwidth. They do this by performing multiple requests in parallel (for ...
-2
votes
3answers
165 views

No route to host after changing interface to static ip [closed]

I installed a Linux (Ubuntu) server inside my home LAN, initially it's automatically configured to use DHCP interface. I'm connecting to this server from another computer using that server's hostname. ...
4
votes
2answers
1k views

How do I apply multiple subnets to a server with one NIC?

I am trying to route multiple IPs through one physical NIC on my dedicated server for use with Proxmox KVM VMs. I have a dedicated server which is currently running Debian 4.4.5-8 with 3 available ip ...
0
votes
1answer
272 views

Linux kernel 3 TCP IP tuning

I found several resources about tuning linux TCP/IP stack parameters in /etc/sysctl.conf for high bandwidth connections, but all refer to kernel 2.6. Does anyone have suggestions about how to tune ...
0
votes
0answers
308 views

How can I setup a Proxy I can sniff traffic from using an ESX vSwitch in promiscuous mode?

I have a pretty specific requirement, detailed below. Here's what I'm not looking for help for, to keep things tidy and on topic: How to configure a standard proxy Any ESX setup required to ...
2
votes
1answer
173 views

Disabling Operating System TCP Management

Is there a way to disable TCP state management of OS, for example on a specific port, or on another ip or if not, disabling the whole tcp management and managing it in an application with root access? ...
1
vote
1answer
172 views

Nmap reporting incorrect results from an idle scan

I have a VPS that I was scanning to make sure everything is in check. A regular SYN scan reports that ports 25 and 80 are open (which they should be). When I run an idle scan however, I get back that ...
4
votes
2answers
3k views

How do I set up IP over FC?

I have 2 systems, with a Broadcom BCM5701 and a LSI7202p, of which are connected with a LC->SC cable. The cards are properly detected in Linux, however I wish to set up IP over FC. I've read online ...
4
votes
3answers
1k views

Backups take so long that the firewall closes the connection

A bit of a mashup of systems here, so bear with me. Essentially, I'm having some trouble using the Backup Exec agent for Oracle, while trying to backup a remote Linux server. The BE agent appears to ...
2
votes
2answers
3k views

Specifying a preferred route when there are multiple links to same network

I have a server with multiple interfaces and IP addresses on the same network. I would like for non-iSCSI traffic to exclusively use one of the interfaces, and for iSCSI traffic to exclusively use the ...
5
votes
2answers
2k views

Answering on the same interface where the request came from

First, I know this is not how IP is intended. But as usual, this is how I need to have it working. I work for a security company. There are at least 2 network interfaces. Both interfaces should have ...
0
votes
2answers
312 views

What is a RP Paket in a tcpdump log?

I have a tcpdump log with the following entry: 14:53:31.428570 IP 10.4.65.65.16666 > 192.168.201.10.80: RP 587:687(100) ack 48545454154 win 0 My Problem is that i have never seen an RP paket ...
4
votes
7answers
6k views

Latency in TCP/IP-over-Ethernet networks

What resources (books, Web pages etc) would you recommend that: explain the causes of latency in TCP/IP-over-Ethernet networks; mention tools for looking out for things that cause latency (e.g. ...
17
votes
2answers
6k views

Unix socket vs TCP/IP host:port

Could someone please describe to me the pros and cons of using a Unix socket file vs a tcp/ip localhost:port when setting up services on a server (Ubuntu, FWIW)? In this particular instance it's for ...
0
votes
1answer
470 views

Linux TCP stack and network cards performance: packets per minute before drop?

how much TCP packets should come at 100/1000mbit network card (not an embedded Realtek's home solution) before the Linux kernel will become unable to process the NIC's buffer resulting in packet drop? ...
-1
votes
2answers
173 views

How works tcp/ip package transport inside Linux OS? [closed]

How works tcp/ip package transport inside Linux OS?
0
votes
1answer
753 views

Linux TCP connection timeout length inconsistent

On the Linux boxes that host the application I work on, we've started seeing an issue where connection attempts against a port on a remote host are sometimes taking longer to come back. As a test, a ...
1
vote
2answers
9k views

Serial port forwarding over TCP/IP (linux server)

I am looking for a way to use a remote serial port on a linux machine over LAN. The machine is running ubuntu 10.04 and I have a arduino board connected to it, that I would like to be able to ...
0
votes
1answer
219 views

Detect and aggregate packets sent to server per TCP port

Is there a way with Ubuntu 10.4LTS to detect and aggregate the number of packets transmitted over every port? In other words, I'd like a process to keep track of the number of packets sent to each ...
0
votes
1answer
2k views

xt_TCPMSS: bad length messages

I'm getting loads of messages like: Jun 23 10:24:20 awakening kernel: [ 1691.596823] xt_TCPMSS: bad length (1492 bytes) Jun 23 10:24:21 awakening kernel: [ 1692.663362] xt_TCPMSS: bad length (1448 ...
1
vote
2answers
1k views

use of tcp_delack_min on redhat linux (kernel 2.6.18)

we're moving from Solaris to Redhat Linux, and trying to duplicate our low-latency setup, that, on solaris, includes the ndd settings related to TCP NO DELAY, and NAGLE ALGORITHM. I got the impression ...
5
votes
6answers
1k views

Looking for an open source real-time network analysis program

Can somebody recommend an open source real-time network analysis program? What I'm looking for the program to do is display a graph of bandwidth usage by IP within our internal network that can ...
2
votes
1answer
3k views

How to set the preferred network interface in linux

I have my network set up like this. http://docs.google.com/Doc?docid=0AZ1YxuLE4djaZGhqN2s1NmRfMjhjNjc0Ym1meg&hl=en In words: I have a machine (Calcium, running Arch Linux) that has two network ...
2
votes
3answers
3k views

Shaping outbound Traffic to Control Download Speeds with Linux

I have a situation where a server makes lots of requests from big webservers all at the same time. Currently, I have not control over the amount of requests or the rate of the requests from the ...
0
votes
3answers
2k views

Cannot ping host stale ARP cache?

I am having a strange issue with a Debian (Lenny/Linux 2.6.26-2-amd64) that has been driving me nuts. On some machines within my network I can ping the host in question just fine, other times I have ...
29
votes
3answers
16k views

Tuning Linux IP routing parameters — secret_interval and tcp_mem

We had a little failover problem with one of our HAProxy VMs today. When we dug into it, we found this: Jan 26 07:41:45 haproxy2 kernel: [226818.070059] __ratelimit: 10 callbacks suppressed Jan 26 ...
6
votes
1answer
1k views

What are some TCP tuning tips for a service hit by iPhone clients on mobile networks like 3G?

I am a developer that has the good+bad situation of designing a network service that will be hit very hard by iPhone clients. The iPhone app has over 10MM downloads in the past year and now I'm ...
15
votes
2answers
18k views

What is the maximum port number?

I'd like to set some linux services to non-standard ports - what's the highest valid port number?
7
votes
6answers
6k views

How do I view the TCP Send and Receive Queue sizes on Windows?

Linux netstat shows send and receive queue sizes. How do I get this info under Windows, specifically Server 2003?
3
votes
2answers
3k views

Using IP alias and route to visit a site through assigned IP address

I want to visit a site through assigned IP address. I run the following commands: ifconfig eth0:1 [ip address] route add -host [the target host ip] dev eth0:1 gw [gateway] This works fine on ...
1
vote
4answers
440 views

Prevent a download to saturate all bandwidth on Linux

In Linux, a single download can use all available bandwidth, so that any other connection can't be started. (e.g. if I am downloading updates, I can't surf the web at the same time) Is there a way to ...
5
votes
4answers
10k views

Running lsof -i shows a lot of connections in CLOSE_WAIT ? Should I worry

So I am running lsof -i | wc -l periodically and it is telling me that out of 420 lines, between 240 and 255 are in CLOSE_WAIT state. How does TCP connections enter this state ? Should I be worried ...
1
vote
2answers
1k views

How do I persist a route in Ubuntu 9.04?

I have a route that I am manually adding at each reboot: route add -net 192.168.126.0/24 gw 192.168.1.1 dev eth1 How can I make this route persistent? I've seen quite a few articles online that ...
2
votes
3answers
7k views

How do I find out my IP address on a unix-like box?

How do I find out my IP address on a unix box? I've tried ifconfig but it doesn't exist on the system.
6
votes
8answers
12k views

How to find the gateway IP address in Linux

What command can you use to find the Gateway IP Address (ie. home router address) for eth0 in Linux? I need to get the IP address from a command line app to use in a shell script.
5
votes
7answers
836 views

Unencrypted equivalent of SSH reverse proxy

I'm looking for an equivalent of this: ssh -R 8888:10.0.0.2:8888 100.101.102.103 ie. make the service running on port 8888 on the local machine (10.0.0.2) look like a locally running service on a ...
3
votes
3answers
8k views

How to increase MTU size on Linux 2.6?

How to increase MTU size on Linux 2.6? Is such a thing possible? If yes, which files (in /etc or elsewhere) must one edit?
12
votes
5answers
56k views

Huge amount of TIME_WAIT connections says netstat

Okay, this is creeping me out - I see about 1500-2500 of these: root@wherever:# netstat Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 ...
2
votes
4answers
6k views

Ethernet Loopback plug - running a ping

For a project at work, I need to be able to test various Ethernet NICs by connecting them to a "loopback adapter plug", like this one on various embedded Linux boxen that come off a production ...
11
votes
6answers
13k views

When IP aliasing how does the OS determine which IP address will be used as source for outbound TCP/IP connections?

I have a server running Ubuntu Server with four IP addresses aliased on a single NIC. eth0 192.168.1.100 eth0:0 192.168.1.101 eth0:1 192.168.1.102 eth0:2 192.168.1.103 (Using ...
6
votes
5answers
3k views

Tunnel over UDP or TCP

Is there a way to create something similar to an IPIP or GRE tunnel only over UDP or TCP? I have a GRE tunnel between two servers and I noticed that sometimes it starts to drop packets. At the same ...