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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Concerned about the content of ip_conntrack

Summary Server OS: Debian Squeeze Web Server: Apache2 IP Tables 'script': arno-iptables-firewall There are 170 entries in /proc/net/ip_conntrack on the server. At present, 134 of those relate to ...
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498 views

Why won't sql server express 2008 service restart after I enable TCP/IP Protocol?

Whenever I enable TCP/IP connections on my SQL Server Express 2008 database server running on Windows XP SP3, I cannot restart the service, it simply states "The request failed or did respond in a ...
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163 views

Issues changing netmask from /24 to /22 on local network

We currently have a network, 192.168.1.0/24. We are close to being out of numbers. If we change the netmask on our servers to /22 (255.255.252.0) all equipment (hosts) with 192.168.1.xx/24 will still ...
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133 views

Multiple systems with the same IP/subnet

Given multiple systems (embedded devices) on a LAN with a factory-set default IP of 192.168.1.1/255.255.255.0, is it possible to communicate with them using UDP broadcast and to receive an answer for ...
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What do all the settings in the Advanced TCP/IP Properties DNS Tab Mean?

Can someone explain TCT/IP > Properties > Advanced > 'DNS' tab please? I know what DNS, primary DNS suffix and DNS suffix are, but this tab has some confusing properties.
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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 ...
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211 views

how to implement elastic ip like architecture in private server farm

what are the ways by which I can implement elastic ip like architecture in my private server farm? There is only one global ip available but I should be able to ssh any server from external network by ...
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85 views

Machine cannot communicate on local network any more

I have a machine that has a problem I've never seen and cannot understand. The machine is a Dell laptop with Windows 7 Ultimate. The user tried to do something fancy with this machine (bridging the ...
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232 views

Solaris VM Experiencing Frequent Timeouts

We are having an issue with all of our Solaris VMs. The issue we're seeing is frequent timeouts when when connecting via SSH or HTTP. It only seems to affect initial connections... when I connect via ...
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3answers
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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 ...
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115 views

connection established, waiting

I work for some administration. We are responsible for app development, I'm personnaly responsible for the software application servers (Glassfish) and there is a team which manages the infrastructure ...
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735 views

Trying to get DNS services running on Windows Server 2008 R2, what am I getting wrong?

Ok, So I am basically trying to get a home server pc up that will provide Domain name services, act as Mail server and web server. I have one static IP, well it's not officially static but hasn't ...
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1answer
559 views

Behaviour of solaris tcp stack with relatively high RTT and bursty traffic

I have an application that is distributing data from New York to Tokyo over TCP running Solaris 10. Mean throughput is < 1Mbps, peak throughput can reach 20-30Mbps for seconds at a time though ...
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4answers
501 views

How can i measure the load of a WAN Connection with Wireshark?

I have a 100 Mbit WAN connection and want to check the load on it for a week. So I put a hub (10/100Mbit) behind the WAN connection and connected a laptop with wireshark on it. Here is now my ...
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1answer
240 views

Users from my ISP's IP range can't hear my radio stream but others can

I'm streaming a radio via Shoutcast server from a PC in my office and ppl from around the world can hear it in browser or via wmedialayer/winamp, but people from my ISP (including me when I use outer ...
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3answers
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How are IP addresses actually assigned?

I'm having a hard time understanding how a governing body assigns IP addresses, companies use BGP to advertise those IPs, and how the internet works. Then, where the hell does DNS come in? Can ...
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1answer
127 views

Can a TIME_WAIT connection be restored?

Is it possible to restore a connection that is in state TIME_WAIT? If not, I use raw packets (forgering the source), is it possible? (Please understand that I do not intend to do bad things, it's ...
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12answers
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Why would you use IPv6 internally?

Of course, I realize the need to go to IPv6 out on the open Internet since we are running out of addresses, but I really don't understand why there is any need to use it on an internal network. I have ...
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1answer
266 views

different ACK behaviors (slowing down throughput?)

I'm running netio (http://freshmeat.net/projects/netio/) on one machine (opensolaris) and contacting two different Linux machines (both on 2.6.18-128.el5 ), machine A and machine B. Machine A has a ...
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949 views

What does this output from HPing mean?

hping command: hping3 -G --rroute $domain -i u1000 Result: len=80 ip=127.0.0.1 ttl=64 DF id=0 sport=0 flags=RA seq=176 win=0 rtt=0.2 ms (same route) len=80 ip=127.0.0.1 ttl=64 DF id=0 sport=0 ...
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Good packet generator tool for IPv6.. Does hping3 support IPv6?

Does anyone of you know any good packet generator tool for IPv6. I am very familiar with hping3, but don't know if it supports IPv6. I am looking for something which can send, tcp, udp, icmp, and ...
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221 views

Building test environment inside Hyper-V - Adding machines into a Domain

I am currently building a test environment with 4 servers inside Hyper-V. One of the servers is a Domain Controller, the other servers will be a member of that domain. All machines are on an ...
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4answers
232 views

About the link layer of TCP/IP

I know there're ethernet,token ring,FDDI ,etc protocat the link layer, but how to know the exact protocol used to perform a specific task,like browsing a web page?
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334 views

Variable port forwarding dependant of iptables rules

I want to setup a special SMTP environment: two different SMTP servers that should be transparently accessed from SMTP clients. Let's say I have a RFC compliant Postfix running at 192.168.0.1:25 and ...
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792 views

Changing TCP/IP IPID sequence generation algorithm on Windows Server

a recent security review on a customers webserver yielded the following results: "[...] The system under test is using incremental ip ids. This means that every outgoing ip packet has an ...
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268 views

How to do MAC based one to one NAT on Linux?

I have a linux machine running ubuntu server with 2NICS (WAN and LAN). I want the LAN side machines to use the linux box as a gateway to get on the internet (WAN side). The only problem is that the ...
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Windows Server 2008 R2 IP Address Binding order

How do I set the order of multiple IP addresses all bound to one ethernet interface?
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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 ...
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66 views

Connecting to a Windows server that has an active VPN connection

In my company we connect to various customers using VPN. We have a dedicated Windows server where the VPN clients are installed, and if we need to do customer support, we have to physically log in to ...
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1answer
2k views

open tcp/ip conenctions count is around 2.1 million!

There are around 1500-2000 users online on this win2008 r2 server on around 50 sites. performance monitor reports around 2.1 million active ip4 conenctions. server is ip6 enabled and has public ip6. ...
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969 views

Accidentally set .255 IP address - how can I ssh to the machine?

A server's static IP address got set to x.x.x.255 on a Windows network, but apparently .255 addresses are broadcast addresses to windows. So now I can't connect to the box from my Windows machine. ...
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408 views

Isolating one router port from the rest

I don't know much about TCP/IP and what I'm trying to do seems fairly basic to me but I can't seem to figure it out. I have one central router connecting to my ISP, and all computers connected to ...
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How is the MTU is 65535 in UDP but ethernet does not allow frame size more than 1500 bytes

I am using a fast ethernet of 100 Mbps, whose frame size is less than 1500 bytes (1472 bytes for payload as per my textbook). In that, I was able to send and receive a UDP packet of message size 65507 ...
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1answer
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Is it possible to disable ARP in Windows 7

I have a unique requirement where I need to disable ARP on a Windows 7 box. In previous Windows versions you could modify the ArpRetryCount in the registry (and set it to 0), but this does not work in ...
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3answers
901 views

Windows 2008 TCP Performance

Some background... I am currently building a domain drop catch application using C#. It uses a single Socket, which sends data through an SslStream. I have spent weeks on the app and I am 100% sure ...
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1answer
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Lots of TIME_WAIT connections in netstat (Windows Server 2008)

I'm having some issues on a Windows 2008 server with some network connections not going through. For instance, in a web application on the server, we need to open a socket connection to another ...
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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 ...
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1answer
410 views

Re-Configuring TCP IP of an AIX system ( LPAR P770/AIX 5.3)

I have serverA and serverB (AIX LPARS on SystemP) I want to switch hostname and IP configurations between serverA and serverB. Is it enough to perform the changes via smitty mktcpip or do I have to ...
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354 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 ...
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3answers
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Routing a PPTP client and VMware Server instance running on the same box

I have a Windows 2003 SBS box. It has 2 physical NIC's: WAN and LAN. The WAN is a public IP. The LAN is a simple 192.168.2.x subnet with Microsoft DHCP Server. Microsoft Routing and Remote Access ...
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2answers
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Windows Server 2008R2 - can't change or remove the default gateway

We've installed VMWare Server 2.0 on Windows 2008R2. After some time playing with it (actually only removing host-only and nat networks, and binding adapters to the specified vmnets) we've noticed a ...
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2answers
109 views

ping problem from a single host

I've a host 10.10.10.1 which i can ping from other machine but ping was sudden stopped from nms machine where the above IP is being monitored 24/7. any help? It has being to work so now i'm unable ...
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Is there a limit to how many sites can be hosted on a single IP address when using HTTP Host Headers on Windows 2008?

For reasons that are lost in the mists of time, our older Windows (2000, 2003) servers have been configured with a "Administrative" IP address and three further "Hosting" IP addresses. There are also ...
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3answers
4k views

TCP/IP communication between Hyper-V host and guests

This may be a simple one. :) I have a simple Hyper-V setup with a few guest os running. The host has 1 physical network adapter with a static IP assigned to it. The guests have network adapters ...
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3answers
324 views

Retrieve a domain name based on an IP Address?

I'm reviewing some apache logs, specifically with respect to downloaded files. I'm interested in knowing, if possible, which domain is responsible for the download, given an IP address. I've given ...
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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. ...
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241 views

What makes SSH so resilient with regards to connectivity issues?

I've rebooted the office's WiFi router and, as expected, my laptop disconnects. Once I reconnect, I notice that my SSH session never dropped. What about the SSH protocol makes this possible? Or does ...
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1answer
748 views

Where do ack-only sent packets come from (on FreeBSD)?

I run the systat -tcp command on a moderately loaded system and see something like this for a 5 second window: /0 /1 /2 /3 /4 /5 /6 /7 /8 /9 /10 Load Average ...
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Why does disabling the TCP/IP NetBIOS Helper service lock me out of GPO?

I disabled TCP/IP NetBIOS Helper and started getting EventIDs 1030 and 1058. This thread said that I'd need to have it enabled. Indeed, when I started it up, the problem immediately went away. My ...
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470 views

TCP/IP Printing Issue in Windows Server 2008

I am running Windows Server 2008 R2 Entrprise in a VM on my laptop. I am having problems setting up a printer. It's an HP PSC 1355 - drivers were installed automatically when I plugged the device into ...