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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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 ...
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1answer
3k views

What am I misunderstanding about calculating MTU?

Okay, I just finished resolving a jumbo frames issue between a few Xserves, a Netgear GSM7224, and a Drobo B800i. It turned out that the Xserves (Mac OS X 10.6.8 Server) and the Drobo B800i accept the ...
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1answer
823 views

One Windows Domain workstation can ping gateway but gets no internet access

One of the (Windows XP SP3) workstations of our Windows Domain could not access internet anymore, this problem suddenly happened overnight. The domain controllers (there are three of them) are all ...
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1answer
163 views

What would cause my SendMail server not to acknowledge receiving a TCP Sequence?

My TCP/IP Stack knowledge is a little rusty so please bear with me.... I have a CentOS 5.7 server with SendMail and am having seeing intermittent timeout issues sending email (particularly larger ...
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1answer
365 views

Restricting ssh tunnel port access by group

My understanding is when creating an ssh tunnel to a remote machine, the ports become open on that machine for anyone to use and connect back to my local box (not just the user who opened the tunnel). ...
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0answers
55 views

netstat showing too many connections (Established) [duplicate]

Possible Duplicate: Too Many ESTABLISHED connection from a single IP address in Apache netstat -ntp |grep 80 shows too many ESTABLISHED connection from single IP address. Around 300 of them ...
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2answers
890 views

How do I fake dropped packets (or actually make them fail)?

Background One of our clients suffers from an intermittant problem with their internet where it will drop packets when a user downloads a large file (their IT is looking into the problem). I have ...
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3answers
3k views

Too Many ESTABLISHED connection from a single IP address in Apache

netstat -ntp |grep 80 shows too many ESTABLISHED connection from single IP address. Around 300 of them and it is not an attack and user is using a 2G connection to access Apache. This is the case ...
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3answers
151 views

Odd ping result on network

Can anyone explain why when I ping 192.168.23.019 it gives me a reply from 192.168.23.17? Then If I ping .23.19 I get a request timed out reply. But I can RDP onto .23.19 These are virtual machines.. ...
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2answers
3k views

Unable to increase the dynamic port range on Windows Server 2008

I'm trying to "tune" the TCP/IP stack on some Windows Server 2008 machines by following the instructions here: http://www.outsystems.com/NetworkForums/ViewTopic.aspx?TopicId=6956&Topic=How-to-tune-...
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1answer
183 views

Can a large number of network hardware interrupts cause a machine to be underutilized?

I don't know much about networking sorry. I'm building a client / server where the server streams a lot of data to the client and I'm trying to maximise throughput (through TCP). If I run both client ...
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4answers
6k views

Error Connection to SQL Server using [HOSTNAME]\instance or [FQDN]\Instance, [IP]\instance working

This one's kind of weird, at least to me. I've got MSSQL server 2k5 (STD) installed on Server 2k3 R2 SP2 (on account of some legacy software that doesn't yet support x64 or Server 2008), using ...
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1answer
50 views

Routing to an external ip

I have a bunch of equipment (RTUs) that connect to a server to download data using a fixed ip and port. Due to change of ISP provider I need to change the ip of the server that handles these RTUs to ...
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3answers
10k views

How to automate DNS server reconfiguration for TCP/IPv4 and TCP/IPv6 in Windows 7?

I need to switch Internet Protocol Version 4 (TCP/IPv4) and Internet Protocol Version 6 (TCP/IPv6) settings for DNS server configuration from "Obtain DNS server address automatically" to hard coded ...
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1answer
637 views

Windows XP SP3 TCP/IP No buffer space available

I have the exactly same problem as here: Windows XP TCP/IP No buffer space available On Windows XP Pro, SP3 if one does an experiment where one tries to open TCP/IP sockets in a loop (bascially, ...
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1answer
2k views

LVS Configuration issue (Using piranha Tool)

I have configured LVS on cent os using piranha tool .I am using vip of internal n/w as gateway for real server we have two NIC one having exteranl Ip and other for internal n/w which is on 192.168.3....
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1answer
439 views

AFP / Apple Filling Protocol aka Netatalk access over Internet

I got a simple cloud server and thought it would be nice to have mac native afp Volumes accesss. Installed Netatalk and this seems to work pretty nice. No sensitive data or something but I don't ...
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1answer
202 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? ...
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2answers
260 views

Using a broadcast or network ID as src IP in PPP?

In case of PPP, are we allowed to use any IP address including broadcast & network id as the source address? For example: 192.168.1.0, 192.168.1.255? One of the customer has configured a DHCP ...
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2answers
7k views

PING: timed out, host unreachable and succes all at once

Is there any logical explanation for this output? I can understand all of the three different results, but all three in one single run of PING? Could my router be defective? I have no internet ...
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2answers
642 views

TCP and Ports Connection

Can more than 1 TCP connection be active at the same time between the two ports on two different host? Please answer.
7
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1answer
1k views

TCP/IP performance tuning under KVM/Qemu

With more and more companies switching to public cloud services, I'm curious what you guys' thoughts are on TCP/IP tuning in the cloud. Is it worth bothering with? Given that you don't have access to ...
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2answers
5k views

How do I prevent excessive ARP requests sent from Windows Server 2003?

OK, I've scoured the 'net already for possible solutions and have found none. Maybe you guys can help me. I have a Windows Server 2003 setup, with a fixed IP on a routed LAN, standard /24 network. ...
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1answer
601 views

PC can't log into SQL Server on different peer network

I have a basic peer network (WORKGROUP) with PCs connected to sql server 2008 on a Windows 7 machine. I took one XP pc and the server home and connected to the server with no problems. When I plugged ...
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1answer
556 views

From TCP/IP network to IPX/SPX network? [closed]

Ok so can a computer from a TCP/IP network communicate with a computer from a IPX/SPX network? If so how will the routers handle the addressing scheme? And what if i wanna telnet that computer from ...
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1answer
109 views

Where is a TCP/IP connection established? [closed]

When a TCP/IP Connection is established, is all handled at the network interface (NIC) level or does it also hit the OS kernel? If so, is it expensive to the CPU (in terms of CPU cycles)?
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4answers
2k views

Determining cause of TCP/IP connect issue without traceroute

I'm trying to connect from a company network to a host (via HTTPS), but my attempts fail with timeout. I can resolve the host. I know the host is up. I know there is a firewall filtering by incoming ...
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2answers
1k views

How to optimize TCP / IP stack in Linux? [closed]

Currently I noticed there are about 15K open connections to localhost. It is mainly connecting to Memcached. I am clueless where I should start to optimize TCP/IP stack. Memcached support UDP, but ...
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1answer
93 views

Maintaining same TCP session, load balacing

With http live streaming (HLS) we need to deliver video segments one after other to the player to play them in a continuous fashion. Segments are present on many streaming servers and we would load ...
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2answers
2k views

why is TCP Connection state not changing from CLOSE_WAIT to CLOSED?

I have a client server application running in: Server: Windows server 2008 R2 [Standard] Client: Windows XP SP3 Workflow: Server listens for client connections at port YY. Client connects to server ...
8
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3answers
4k views

Where is the documentation that states TCP and UDP source port should be over 1024 and random?

I am having a hard time to find where it is documented that the source port should be random and in the range 1024-65535. In which RFC is this documented? Edit: First reference for privileged ports ...
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1answer
320 views

Detecting TCP/IP connection drop issues in my application

I have a desktop application which talks to a server using TCP/IP. It was working before but now we are running into an issue. The log message on the server shows that the socket is disconnected after ...
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1answer
276 views

How does tcp keep a connection alive? [closed]

In http ( over tcp) there is a header which called keep "alive" I dont understand how a connection can be open in tcp if all packets come from different source ( router decision - over the internet)
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1answer
1k views

Multiple Homed Windows 2008 Server / Windows 7 Client

I have a small Windows 2008 network, with some Windows 7 clients. The clients are both laptops with docking stations and I would like them to communicate with the Windows 2008 server (for filesharing) ...
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1answer
244 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 ...
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1answer
1k views

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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1answer
566 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 ...
2
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1answer
176 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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2answers
137 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 ...
6
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2answers
17k views

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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2answers
5k 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 ...
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2answers
225 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 ...
3
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1answer
96 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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2answers
242 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 ...
4
votes
3answers
2k 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 ...
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1answer
118 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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1answer
783 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 ...
4
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1answer
634 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
528 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
244 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 ...