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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1answer
22 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 ...
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1answer
19 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 ...
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3answers
35 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 ...
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0answers
18 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 ...
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0answers
18 views
TCPIP Sockets are dropped unexpectedly
We have a classic Web Client Server application environment. The Web servers are IIS 7.5 cgi is performed by PHP and a JAVA app listens on the App Layer for requests from the PHP script. The PHP opens ...
0
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0answers
43 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 ...
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2answers
65 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
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2answers
89 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
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1answer
95 views
Q: Long TCP/IP Connect time (20-40s) with Apache 2.4, mod_proxy_ajp, Tomcat 7.0.39 running on Windows Server 2008 R2
I have a problem where the initial connection to a Apache HTTP Server is taking very long (20-40s), but the subsequent connection is very fast (<50ms). I use Apache HTTP Server as a load balancer ...
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1answer
139 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
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1answer
65 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 ...
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0answers
34 views
Effects of IW10 (initcwnd 10 initrwnd 10) on high speed LAN based TCP/IP communications?
What does changing the number of packets sent during the initial congestion window to 10 have on LAN connections?
Via:
ip route change default via GATEWAY dev INTERFACE initcwnd 10 initrwnd 10
Is ...
3
votes
3answers
116 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 ...
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4answers
102 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
108 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 ...
2
votes
1answer
96 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
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2answers
85 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
527 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
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0answers
42 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
64 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
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1answer
249 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
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1answer
85 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
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2answers
162 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
83 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 ...
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2answers
82 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
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1answer
30 views
Online vendors for a Java application as TCP listener [closed]
Which available hosting services can i use to host a Java service application (TcpListener), which uses TCP/IP layer only (not web)?
I want to make it available for TcpClient across the internet. Now ...
0
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0answers
20 views
Amanda Configuration
I had 10 client systems which are needed to backup where I installed amanda 3.3 server. In my server machine, I had edited the configuration amanda.conf but still not working I had amanda 2.6.1-p2 in ...
0
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1answer
74 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
54 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 ...
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votes
3answers
112 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. ...
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votes
2answers
97 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
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2answers
413 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
3answers
833 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
439 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 ...
1
vote
1answer
292 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
94 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
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0answers
228 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
764 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 ...
3
votes
1answer
217 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 ...
0
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0answers
44 views
How to tell which device might be dropping packets
We are trying to diagnose a chronic disconnection issue. Overnight, nearly every night, our HTTP long poll client is disconnected from the server. The most likely proximate cause is that the longpoll ...
1
vote
4answers
94 views
Just one client bound to address and port: does it make a difference broadcast versus unicast in terms of overhead?
Scenario:
I am implementing failed over for a network node, so my idea is to make the master node listens on a broadcast ip address and port. If the master node fails, another failover node will ...
2
votes
1answer
71 views
Host data transfer limit calculations and network protocol headers
OK, this might be a really stupid question, but...
I'm building a web app that utilises websockets. There's fairly rapid messaging going on, so I've been taking a look at the network traffic with ...
0
votes
1answer
145 views
multicast streaming, too much network traffic?
I am thinking of switching our streaming servers to use multicasting instead of registering multiple clients and duplicating the streams manually on the server. It seems to work very well. However, I ...
1
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0answers
354 views
NIC Teaming , Multi-Homed, Active/Passive
I'm fairly new to NIC Teaming.. So I apologize if I’m not making any sense while describing this. I’ve, of course, set up plenty of simple Active/Active NIC teams for our servers without any issues ...
2
votes
1answer
84 views
IPv6 & ReservedPorts in Windows Server 2008 registry
I have HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\ReservedPorts set to 1153-1153, but sometimes IPv6 programs get assigned this port. Is this setting for IPv4 only? Is ...
1
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2answers
614 views
Raw TCP/IP port forwarding software
I have server which IP address is whitelisted in some external system. And also, I have a few software developers with dynamic IPs which develop software and they need to connect to external system, ...
0
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0answers
77 views
Unable to ping one machine on the network
I have one machine on the network that can't be pinged (by name or IP) or accessed with WMI by other machines on the network. So far I have tried:
Disabled firewall and AV
Put onto a workgroup then ...
0
votes
1answer
132 views
Can ranges overlap in ReservedPorts?
The value ReservedPorts in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters contains a list of port ranges to reserve so the system won't assign them to programs dynamically.
...
3
votes
2answers
729 views
IP address used by nslookup and ping is different
I have a web server hosted in the network. It has a domain name registered. However, I also host a DNS server for the LAN. So, when someone wants to access the web server, it would check the DNS ...
2
votes
1answer
1k views
Why ARP request is unicast?
I have a wireshark capture here that indicating a unicast ARP request from source to destination. As per my understanding ARP requests (including gratutious ARP) use broadcast.
In what case the ...
