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"

learn more… | top users | synonyms

0
votes
1answer
3k views

Where to find WINS IP address in registry?

I have been writting a powershell script to remotely dump the TCPIP information from the registry of machines in my Windows Domain. I was able to dump the default gateway, subnet mask, DHCP server ...
-1
votes
1answer
104 views

Need help routing Cisco network- IP routing [closed]

In the above network, can you help me configure routes so the computers on the left can see the computers on the right, and vice versa? I know the syntax of the command is ip route {network ...
0
votes
0answers
361 views

SSH attempt keeps failing, syn+ack does not reach machine

1 0.000000 10.0.0.1 10.1.1.0 TCP 66 49285 > ssh [SYN] Seq=0 Win=8192 Len=0 MSS=1260 WS=256 SACK_PERM=1 2 0.001160 10.1.1.0 10.0.0.1 TCP 66 ssh > 49285 [SYN, ACK] Seq=0 ...
1
vote
1answer
328 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 ...
0
votes
1answer
450 views

is it possible to use ms loop back adapter to setup local vlan

Is it possible to use Microsoft Loop back adapter to set up Lan connection between two computer which is logically isolated from the main network? 1st computer: has a regular ip stack 192.168.1.x ...
1
vote
2answers
2k views

How to globally limit total number of TCP connections with iptables?

I'm having quite a difficult time figuring out how to REJECT both inbound and outbound connections from a machine with iptables once the total number of TCP connections hits a global maximum without ...
-1
votes
1answer
147 views

Is their an official tool to tweak Windows 2008 server TCP configurations?

We are running scripts that initiates numerous TCP connections and disconnects right away. It's just to test if the remote report is opened and responsive. But we are having random strange issues ...
2
votes
1answer
72 views

Random three minute delay for database server connect

we use InterBase on a Windows 2003 server, and in random intervals the client connection to the server takes 180 seconds (three minute) longer than usual. The application does not "hang" with the ...
0
votes
0answers
66 views

Linux + OpenVPN + SNAT + Failure on client grab the reply to it's own generated traffic

Ok, I'm really desesperate I need to release an openvpn deploy to get rid of a dying server. On the subject: I installed OpenVPN with a routed interface (tun0) into a server with a public IP + 3 ...
1
vote
1answer
619 views

Frequent interruptions of SSH connection to VPS

My SSH sessions die at what seem like random times - response will stop, and then a few seconds later PuTTY will pop up a message with, "Server unexpectedly closed network connection." It seems to ...
-3
votes
2answers
353 views

what is meant by application layer protocols being encapsulated into transport layer protocols? [closed]

I am reading this wikipedia article: http://en.wikipedia.org/wiki/TCP/IP_model#Application_layer It talks about how TCP and UDP are transport layer protocols which are designed to connect one host ...
0
votes
2answers
6k views

Slow data transfer between Server 2012 and Windows XP/7 Clients

I've installed a new Dell PowerEdge R720 server at a small company which eight workstations. It is running Windows Server 2012 Standard. I've then installed Hyper-V (role) onto the server and created ...
4
votes
1answer
127 views

TCP works for a while, then fails, why?

This comes from an implementation of OpenStack, and we have a fix, but I don't understand why we need this fix. My machine has an ip of 192.168.20.45 My default gateway (pfsense) has an ip of ...
1
vote
1answer
1k views

Determing MSS value on Windows Server

In this Technet article about the MSS limitations of Windows Server 2008, it mentions: After analyzing the network trace collected on the source Windows 2008 Server, we found out that the remote ...
3
votes
1answer
653 views

How to debug why WAN TCP/IP throughput is lower than expected?

I'm trying to figure out why tcp/ip throughput between two hosts I control is much lower than expected. Host A: internet connectivity provided by Comcast (Residential) in Boston Metro -- can ...
3
votes
1answer
230 views

TCP Congestion Window on Windows Server 2003

After reading this blog post by Ben Strong, I started looking on the internet for information on how the Initial Window size could be manipulated on Microsoft Windows Server 2003 (R2, 64bit in case it ...
0
votes
1answer
2k views

TCP/IP connection to SQL Express works on HALF of the clients in a WORKGROUP

So far I have learned the following facts about Microsoft SQL Server Express, including version 2012, and earlier versions like 2008R2, and 2008, and for the most part all the way back to SQL Server ...
1
vote
3answers
567 views

Max client TCP connections through a router

I've just been thinking about what the maximum number of client connections would be out of my home LAN to a single server on the internet. My home router is also NAT'ing the connections to convert ...
0
votes
1answer
84 views

RPC SERVER is unavailable

windows 2003 is getting this error. restart the machine or just the network connection fix the problem. date and time is the same one. tcp/ip is started and running remote registry is running the ...
0
votes
0answers
146 views

tcp recycle and retransmission

TCP recycle reduces TIME WAIT by reusing sockets. It avoids collision with older packets by storing timestamp and receives packets with greater TCP timestamp. What happens when the client retransmits ...
0
votes
2answers
253 views

How does VPN software 'hijack' packets for tunneling?

My current mental model An application interacts with the operating system to produce an OSI model stack-based packet process - subsequent layers of encapsulation Somewhere along the line before the ...
0
votes
2answers
140 views

Thousands of port 25 connections

Tonight a few IP addresses made almost 2500 connections on port 25 of a mail server. 2500 is the max limit, and 50 or less simultaneous connections is normal. They did nothing once they made the ...
0
votes
1answer
669 views

Long TCP/IP Connect time (20-40s) with Apache 2.4, mod_proxy_ajp, Tomcat 7.0.39 running on Windows Server 2008 R2

The initial connection to an Apache HTTP Server is taking a very long time (20-40s), but the subsequent connection is very fast (<50ms). I use Apache HTTP Server as a load balancer using ...
1
vote
2answers
1k 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 ...
0
votes
1answer
134 views

Multi-IP server: how do programs know which IP to use?

I recently tried adding second IP address to our server for various reasons and found that now when I check netstat -anob there are many programs/services listening and establishing connections to ...
4
votes
3answers
2k views

Practical Anycast

I've read How can I send visitors to the closest server using DNS? post, but there's still some thing, on a practical level that I don't understand. Say I have two servers. One in NY another in ...
1
vote
4answers
3k views

Smaller network packets vs bigger packets - confused

Some are saying that bigger packets are better to send then smaller. But in this app: http://media.pearsoncmg.com/aw/aw_kurose_network_2/applets/message/messagesegmentation.html The lower the packet ...
1
vote
1answer
1k views

How to setup an TCP/IP proxy with traffic interception, for MS SQL traffic in this case

I would like to setup an MS SQL proxy server. It should forward all requests 1:1 and make it possible to log them, and modify some of the requests or answers according to some replacement rules I ...
3
votes
1answer
265 views

Given a 100mbit connection, what is your max downstream speed?

I'm a (very) junior sysadmin and was asked this question on an interview. The answer was 96mbit/s. I know this is related to network overhead but I cannot find any good information on why this ...
1
vote
2answers
226 views

How to implement firewall in LAN(out of users' os) like EC2 have done?

In aws ec2, users can set up security groups which works like a firewall, usually, firewall work behind a gateway/nat server, however, I found that firewall in EC2 works in the LAN, too. For example, ...
2
votes
3answers
4k 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
0answers
101 views

50% Throughput on direct connect XCOPY transfer

I have two Dell Servers with multiple gigabit network ports each. These run a sync process using XCOPY. To improve throughput and reduce overall network impact, I have dedicated a connection on each ...
2
votes
2answers
101 views

Special Routing and NAT requirement

I have a rather special routing and NAT issue which I hope I can fix somehow. Inside my company we run a supernet like 192.168.0.0/21 (192.168.0.1 - 192.168.7.254) All computers have this subnet mask, ...
1
vote
1answer
1k views

Best way to calculate optimal subnet masks for a range of IP addresses? [closed]

I thought I saw a tool like this once upon a time, but can't find it anymore... Anyone know a tool that would take a free range of IP addresses (as in start / end) and calculate a set of submasks ...
0
votes
1answer
132 views

TCP/UDP Connection States documentation

Does anyone know where to find documentation for TCP/UDP connection states? Preferably non-Microsoft with unix backing. Basically, I'm looking for more information about TCP established, TCP ...
1
vote
2answers
1k views

Connecting to MS SQL 2012 with TCP/IP

I'm trying to enable TCP/IP connections on a SQL Express 2012 database, and it seems as though I'm missing a step somewhere. To enable it, I: Opened SQL Server Configuration Manager Selected ...
0
votes
1answer
408 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
2answers
399 views

Why tcp/ip model is being used for Developing Protocols and not OSI [closed]

why TCP/IP model is used for designing Protocols and why not OSI model,if i am not wrong OSI is the first reference model and in TCP/IP model same concept is followed but coupled with other layers. ...
0
votes
1answer
296 views

SQL Server 2008 intermitent error 40 running parallel queries

Here's our setup : We are using Red Gate SQL Multi-Script to run queries on our ~1000 databases which reside on a single SQL Server 2008. SQL Multi Script can be configured to run queries in ...
0
votes
2answers
73 views

Why would a process be showing an outbound connection from a 169.254 address when there's no unconfigured adapter?

I have a system that has several network adapters, only one of which is enabled. That adapter has ipv4 only enabled and it has a single IP address. It was previously part of a team. The team was ...
-2
votes
3answers
283 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. ...
-5
votes
2answers
512 views

Why do we need logical addressing [duplicate]

Possible Duplicate: Why couldn’t MAC addresses be used instead of IPv4|6 for networking? If physical address or Mac address is unique why do we need logical addressing? This because ...
0
votes
2answers
4k views

Problems with MDNS flooding on port 5353 UDP

I am running into a big issue at a small network i manage. This network is an Apple network, with airport extremes, expresses, mac book pro's, imac's, ipads, iphones etc... I went to add something to ...
3
votes
4answers
3k views

Windows 7 DHCP Default Gateway not Overridden by manual Default Gateway

We have recently installed Windows 7 for student computers. All student computers must be routed through our content filter which is located at 192.168.0.63. This was done in WinXP by adding a Default ...
4
votes
2answers
2k 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 ...
5
votes
1answer
886 views

Where are my TIME_WAITs on Mac OS X?

No TIME_WAITs on Mac OS X Normally, when a TCP connection is closed, the socket on the side where close() is called first is left in the TIME_WAIT state. When one of the peers is a Mac OS X (Lion) ...
5
votes
1answer
144 views

Sender Information Not Cached on the Receiver During an ARP Request

I'm currently trying to get my head around more advanced networking concepts. The way I am doing this is by going on one of the servers I look after as a sysadmin and running network captures to see ...
1
vote
0answers
368 views

switch OFF syn cookies

We have several servers they have public IP's, but work together (one is with Load Balancer, orther with Apache Web server, other with MySQL and so on. Most of the ports are fire-walled, so only ...
3
votes
2answers
2k views

custom route not working on windows

My windows laptop is directly connected to 192.168.1.0/24 (wireless lan). I access 10.21.0.0/16 though a router that is connected to both networks. The routing works fine with this configuration. I ...
6
votes
1answer
1k views

HTTP, TCP, UDP and connectionless

I am a bit confused with HTTP lately. Some facts are that TCP can operate connection orientated or connectionless, this I understand. TCP though is connection-oriented while UDP is connectionless ...