Tagged Questions

TCP and IP are two important protocols used in networking today. Due to their importance, the Internet Protocol Suite is also commonly known as "TCP/IP"

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2
votes
2answers
6k views

Anyone know of a free flood ping utility for Windows? [closed]

Does anyone know of a free ping flood (some people call it flood ping) utility for Windows? I want something portable that I can install anywhere. I use ping flooding to primarily test for packet loss ...
8
votes
1answer
7k views

What is the maximum number of TCP connections I can have in Windows Server 2008?

I would like to have as many connections (single connections from many different clients) as humanly possible in a server running on Windows Server 2008, in order to support a Comet-style application. ...
9
votes
4answers
19k views

What does a DNS request look like?

I have seen what the text representation of an HTTP request is, but what does a DNS request look like? Where in the data is the location of the URL you are trying to locate? Also, how is the ...
1
vote
4answers
5k views

Diagnosing and debugging LAN congestion / connection issues

What are the top N tools / methodologies used to diagnose and repair network issues? Given a LAN, for example, where users are able to consistently ping an outside server, but any data intensive ...
0
votes
8answers
10k views

How can I add more than 255 machines to a single Class C network? [duplicate]

Possible Duplicate: How does Subnetting Work? I'm mainly a programmer. I have no idea beyond some basic theory when it comes to Networking/Administrating. My university feels that we ...
0
votes
1answer
183 views

Need help getting StateServer to work, trying to decipher WireShark to figure out why

I'm using WireShark to try to figure out why I can't get my ASP.NET application (which is deployed to IIS6) to use a remote ASP.NET StateServer. For the record, StateServer works if my application is ...
1
vote
1answer
485 views

Moxa serial-to-ethernet connection problem

We have a Windows 2003 Server (32-bit) running in VMWare and connecting to 2 Moxa NPort 5450 serial-to-ethernet devices. We are experiencing a sporadic "disconnect" with the serial devices attached ...
0
votes
1answer
754 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 ...
0
votes
2answers
243 views

Network Speed Limit

I have a nic "Local Network" and I would like to limit throughput speed for it to 1480kb/s and 208kb/s upload How can I do that?
1
vote
2answers
10k 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 ...
2
votes
3answers
635 views

Can ping server but no telnet or www

I have a NAS (iomega home media 1TB) plugged in router using 1Gb ethernet cable. Occasionally I lose access to it, I can ping it by static ip, nmap to see all open ports but can't telnet to it. Also ...
1
vote
1answer
1k views

TCP RST Reset Every 5 Minutes on Windows 2003 sp2

Recently I had a web developer come to me and ask why he was receiving connection errors in his app that was accessing a sql database. So, I went through my normal trouble shooting steps to isolate ...
2
votes
3answers
11k views

What does the IP “192.168.1.1/24” indicate? [duplicate]

Possible Duplicate: Server Fault Wiki: How does Subnetting Work? I'm setting up rsync and I see this in the config file: hosts allow = 127.0.0.1 192.168.1.1/24 Does this indicate that ...
2
votes
0answers
962 views

How to know the source of certain TCP traffic on AIX

We have two AIX boxes, one for production system and another for testing. both systems are running ATM machine switches, where the ATM device is connected via TCP socket. we had an issue on ...
3
votes
2answers
2k views

How to get a service to listen on port 80 on Windows Server 2003

I've coded a custom windows service that listens on TCP port 80 but when I try to install it on a Windows Server 2003 machine it fails to start because some other service is already listening on that ...
1
vote
2answers
497 views

Static IP for dynamic IP

I have a dynamic IP address. I would like to have a static IP, but Virgin Media don't allow static IPs for residential broadband services, even if you ask them really nicely and offer to pay for it ...
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 ...
3
votes
1answer
827 views

Solaris TCP stack tuning

We have a large web project (about 2-3k requests per second), using haproxy (http://haproxy.1wt.eu/) as a frontend and load balancer between the java application servers. The frontend (haproxy) is ...
1
vote
1answer
1k views

How can I make WinXP bind to ports other than 1025-5000 for outgoing TCP connections?

(I originally posted a similar question on StackOverflow but readers recommended I post here instead) When you create outgoing TCP connections, most applications let the operating system choose which ...
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
2answers
619 views

Recommendation for a non-standard SSL port

On our server I have a single IP, and need to host 2 different SSL sites. Sites have different owners so have different SSL certificates, and can't share the same certificate with SAN. So as a last ...
8
votes
3answers
2k views

Can I make TCP/IP session to run less than 60 seconds?

Our server is overloaded with TCP/IP sessions, we have 1200 - 1500 of them. Most of them are hanging in TIME_OUT state. It turns out that a connection in TIME_OUT state occupies a socket until 60 ...
3
votes
3answers
10k views

wireshark http POST

I would like to have a http POST request method CAPTURE filter. I know it is easy to do it by display filter http.request.method==POST but I need tcpdump compatible. I wrote tcp dst port 80 and ...
2
votes
1answer
4k 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 ...
1
vote
0answers
770 views

Network Transfer Rate on SMB/FTP

We're trying to optimise our network transfer rate from the client PCs to the file server, but having no luck. If I run an iperf test between a client PC (Windows XP) and our server (Linux) with a ...
2
votes
1answer
153 views

NetDiag + TCP Blocking?

We are facing some issue with the sharepoint 2007 timer jobs everyday at a specific time, so decide to track the tcp blocking informartion during those hours using NetDiag tool. We are not able to ...
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 ...
2
votes
2answers
126 views

How can I verify the integrity of a WAN connection?

We have two scanners in our branch office which upload images to the head office via FTP. In the last week, both scanners have started delivering a lot of corrupted images. I suspect that the problem ...
4
votes
2answers
699 views

Rapidly changing public IP addresses on certain networks?

I run/develop an online game where many of our users are in southeast asia. I recently went to southeast asia and made an alarming discovery. Anywhere I got internet access, whether it was via 3G, a ...
0
votes
1answer
932 views

How to enable TCP Vegas on Centos 5.4?

I'm trying to enable TCP Vegas congestion control on Centos 5.4 box. According to Vegas home page it is as simple as echo 1 > /proc/sys/net/ipv4/tcp_vegas_cong_avoid but this file does not exist. I ...
1
vote
1answer
1k views

Linux IPTables / routing issue

EDIT 1/3/10 22:00 GMT - rewrote some of it after further investigation It has been a while since I looked at IPtables and I seem to be worse than before as I can not seem to get my webserver online. ...
1
vote
1answer
790 views

Solaris TCP/IP performance tuning

I am trying to tune a high message traffic system running on Solaris. The architecture is a large number (600) of clients which connect via TCP to a big Solaris server and then send/receive relatively ...
-1
votes
2answers
480 views

monitoring TCP/IP performance on Solaris

I am trying to tune a high message traffic system running on Solaris. The architecture is a large number (600) of clients which connect via TCP to a big Solaris server and then send/receive ...
1
vote
3answers
3k views

how do i change outgoing ip address for server centos

I need to make sure my clients outgoing ip address uses the dedicated ip they are assigned. For example, site123.com has an ip of 123.123.123.2(eth0:1) (resolves fine when incoming) but it is using ...
2
votes
3answers
1k views

Good (free / open source) tools for analyzing TCP capture files?

I use wireshark and microsoft network monitor extensively, but I'm curious if there are other good (hopefully free / open source) software packages for analyzing TCP/IP traffic? I'm especially ...
1
vote
2answers
3k views

What is the Ethernet Type II Protocol number for an ICMP echo request and reply?

Hi I wanted to know what the Ethernet II Protocol number for an ICMP echo request and also for a ICMP echo reply?
2
votes
3answers
314 views

MAC address to IP Address on Same LAN in Windows

Is there some way for me to find IP address of machine connected in same LAN from its MAC address.
3
votes
2answers
1k views

TCP/IP Stack in Windows Server 2008 vs Windows 7 Ultimate

Does anyone know the details as to the differences between the TCP/IP stack in Windows Server 2008 (Standard) vs Windows 7 Ultimate? This question pertains to TCP/IP ONLY. I know that Windows 7 and ...
1
vote
1answer
1k views

Can someone explain what this vulnerability means?

I'm having a bit of a problem getting my head round what this vulnerability means, can someone help me understand this? I'm particularly puzzled by the RESULTS section. Why would source port 25 be ...
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 ...
1
vote
1answer
4k views

Windows XP TCP/IP No buffer space available

I have isolated a problem down to this: On Windows XP Pro, SP2 if one does an experiment where one tries to open TCP/IP sockets in a loop (bascially, listen port 7000, listen port 7001, etc.) After ...
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
19k 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?
2
votes
4answers
3k views

Using SAN Fiber Channel network for TCP/IP, possible?

I would like to know if it is possible to use the FC-switch (that is used for a SAN) also for TCP/IP traffic. We have servers (virtual machines) that must have a fast network for copying much data. ...
3
votes
1answer
657 views

How to make Windows honour an ICMP Connection Refused message after a TCP connection attempt

We have a tool which is used to manage a server process remotely over TCP. One of the tools features is to check if the server is running by attempting to connect to the server in a loop for a given ...
0
votes
1answer
649 views

BT Router and Assign Multiple IP Addresses

We have bt router model: BT2700HGV , 2wire, can someone tell me if this router supports this Scenario is I have 2 webservers and want them to be available publicly , thanks update: A bit more ...
4
votes
2answers
11k views

UNC Path fails by IP “no network provider accepted the given network path”, but works using hostname

I have an unusual problem with a Windows Server 2003 (Standard x86) box. It appears the machine will not accept connections to its shares (locally and from other domain member servers) by using its ...