TCP stands for Transmission Control Protocol and is one of the core protocols of the Internet Protocol Suite. TCP complements the Internet Protocol (IP), and therefore the entire suite is commonly referred to as TCP/IP.

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27 views

Relationship between tcp state TIME_WAIT & HTTP keep-alive

What is the relationship between keep-alive on a HTTP request and a tcp socket in TIME_WAIT - should they be correlated? Furthermore, should system and web server settings be aligned e.g. ...
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8 views

Source ip based Anycast-BGP?

I'm just getting interested in networking so don't be too harsh on me :) Ideal: 2 servers with shared ip; ip X Client 1 pings ip X > always server A Client 2 pings ip X > always server B ...
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1answer
23 views

Geo distributed ip [duplicate]

When i ping 8.8.8.8 from my home computer (europe) i get around 26 ms latency. When i ping 8.8.8.8 from a server(US) i get around 1 ms latency. When i ping my (US) server from home (europe) i have 130 ...
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0answers
9 views

HAProxy RTMP (TCP) load balancing

I am using HAProxy as load balancer for the RTMP protocol. For now it's working very very good but I have one small problem. I want to send the client's IP on the RTMP request after the load balancer. ...
0
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1answer
60 views

How to trace dropped TCP connections?

Trying to help someone with a situation where TCP connections get mysteriously dropped after a few minutes for no apparent reason (this happens even with non idle connections). Both client and server ...
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29 views

Many output tcp connections in SYN_SENT status showed up [duplicate]

I manage some Linux servers, I find a strange phenomenon since last month. When I'm running netstat command, it shows me too many tcp connections point to specific ports like 22 or 80 of different ...
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12 views

apache bench handshake failure server sending TCP FIN

I am trying to verify handshake performance by sending number of requests with out setting concurrency with below command. ab -k -n 18750 -c 1 -Z AES128-SHA -f TLS1.3 ...
0
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4answers
89 views

Cannot work out what is using port 8080

In Windows Server 2003 R2 64 Bit SP2 I have an app which will only use port 8080 but something is already using it. I would be happy to just kill whatever is using it but I can't work out what it is. ...
0
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1answer
39 views

Existing TCP Relay Solutions [closed]

I have a scenario which requires the use of a TCP Relay. Before I set out to write something custom, I wanted to see if anyone knows of existing software that can do this for me. I have 2 devices on ...
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1answer
35 views

TCP ports duplication [closed]

I need to communicate server1 to server2. Server1 should have to fetch some records from Server2 when we execute program.exe will make server1 to fetch server2 When I gave netstat -an | find ...
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2answers
24 views

Wireshark “length” column - what does it include?

Can anyone tell me what the "Length" column in WireShark refers to? I'm pretty sure it's the "size" of the entire frame on the wire. I did some calculations, but I didn't get the number that ...
1
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1answer
39 views

HTTP not finishing over LAN. Hardware cause?

On a customer server running Apache 2.2 on Windows server 2012 we're noticing that from time to time, some requests to the server never finish. Using wireshark I've found a bunch of duplicate ACKs get ...
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0answers
35 views

Cannot connect to TCP service from remote host

I have two servers running RHEL 5.8. SRV1 (10.58.192.36) has a service running on port 9002 and I need to connect to this service from SRV2 (10.58.192.42). [root@SRV1 ~]# netstat -anp | grep 9002 tcp ...
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0answers
44 views

TCP [RST,ACK] ignored

I have a Windows 2008 server and an application that connects over Internet to it. From time to time I see that I receive a TCP [RST, ACK] that is ignored by my application. Using TCPViewer I still ...
2
votes
1answer
52 views

iptables: match only the first packet of established TCP-connection

In my Apache-logfiles I find a lot of entries that contain "GET /w00tw00t.at.ISC.SANS.DFind:) HTTP/1.1" 400 or similar crap. They come from non-RFC2616-connections (HTTP/1.1 without hostname). I ...
0
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0answers
24 views

Networking issue in IBM x3650 after install Ubuntu 14.04

I have a problem making TCP connections after a fresh Ubuntu 14.04 installation. First of all, after booting the interface is always off. In my case the interface is manually configured and named em2. ...
0
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1answer
30 views

High number of TCP RST packets

Whilst looking into some transient network issues, I have noticed what seems to be a high number of RST packets received: Tcp: 40091950 active connections openings 44754733 passive connection ...
10
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1answer
215 views

Under what circumstances is TCP-over-TCP performing significantly worse than TCP alone (2014)?

Many admins keep perpetuating - on ServerFault and elsewhere - how bad of an idea TCP-over-TCP is, e.g. in VPNs. That even the slightest packet loss will make one suffer from at least severe ...
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0answers
17 views

Duplicated TCP SYN Messages: second one is ACKed, but the connection is finally FINed

While wring a TCP server program, I found a very interesting symptoms. clients sends a first SYN packet. (server does not show any reactions.) clients sends another SYN packet after one second. ...
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1answer
24 views

Application protocol-based port forwarding/redirection [closed]

I need to split traffic on port 80 between HTTP and non-HTTP, and internally forward HTTP traffic to a port nginx will listen to, and non-HTTP traffic to port 22. Does anyone know of a piece of ...
1
vote
2answers
89 views

Send Text String to a Socket In Windows

I have a server that has an open socket that listens for a particular text string on it in order to perform an action. Our linux machines send this data via: echo "text_string" | nc -w 2 ...
-1
votes
1answer
40 views

FTP upload slows down when devices are connected via hub [closed]

I have a setup with a network hub and three Ethernet devices. One of them is a PC (running windows XP), two others are hardware components that need to communicate with each other over the network. ...
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0answers
28 views

Why do some outgoing IP traffic not contain UID information?

I am doing egress logging on my server using IPTABLES with the following line which is supposed to provide UID information on all traffic that is logged: -A OUTPUT -j LOG --log-prefix "IPTABLES(O): " ...
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2answers
57 views

tcp ack delay almost 600ms, is this all right?

As far as I konw, tcp delay ack always 200ms, but now in my production environment it delay almost 600ms, my environment is below: ubuntu 11.04 48G memory 16 core, load not heavy; I catch packet in ...
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0answers
34 views

Why do I get connection timeouts to private services in Azure?

I seem to be seeing this with both my SQL Server, and my MongoDB replica set. I only get a handful a day, but it still concerns me. I am getting a timeout when trying to open a new connection to the ...
1
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0answers
44 views

TCP Window Size Allocation, TCP Window Zero Errors and Network Latency

My mind is about to explode as everyone is always blaming the network guys for disconnections and slowness in the networks, but Solarwinds Reports that all utilization in the network devices and links ...
1
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2answers
247 views

What does TCP: too many orphaned sockets mean?

When I use dmesg to look at linux kernel messages, I see a flood of.... TCP: too many orphaned sockets messages. My guess is this is sockets that are hanging around in TIME_WAIT after being closed ...
0
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0answers
51 views

Connection Timeout Issues - Solaris 11 SPARC

We're currently running some performance tests using Solaris 11 (SPARC) on some large hardware. The tests, which consist of sending SOAP requests (50kb per request), are running well up until we get ...
2
votes
2answers
80 views

TCP under OpenVPN is very slow (tsg attached)

I have a very weird problem with OpenVPN. Most VPNs work fine, except this one. Here I get very low performance from TCP connections, but the CPU load is low (so, not a CPU issue). OpenVPN is ...
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0answers
34 views

Single TCP-CLOSE_WAIT connection brings down application till restart

Recently found a behaviour where my application had a connection in TCP Close_wait state till the app was restarted (after about 5 hours). But during this period the SUnreclaim space was also ...
0
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1answer
35 views

cannot send emails to other Web servers

I'm trying to limit my server's open ports in CSF. The IPv4 port settings include: # Allow incoming TCP ports TCP_IN = "22,25,53,80,110,143,443,587,3654,53343” # Allow outgoing TCP ports TCP_OUT = ...
0
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1answer
38 views

What do I need to consider when setting TCP idle timeouts?

What's purpose of having a [low] TCP idle timeouts? E.g., why have a 60 second timeout on a firewall or load-balancer? Is it a memory management or /performance optimization thing? Is there a security ...
1
vote
1answer
81 views

Linux iptables - reject tcp SYN with RST

I am doing an implementation on a linux machine to reject incoming telnet requests from wan side telnet port 8023. The functionality is achieved by using the below iptables rules. The first rule in ...
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0answers
33 views

periodic connection timeouts to nginx server

We have the following setup: One nginx server as a loadbalancer in front of four worker application servers. The nginx server get about 100 requests per second, sometimes more that that, active ...
0
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0answers
19 views

Want to route NFS response via an interface. What will the source ip of the packets being sent out?

The NFS server is listening on an interface for a new connection, once a new TCP connection is established the NFS operation is carried out. I'd like to send this NFS response via a different ...
0
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0answers
88 views

Proxy / Squid 2.7 / Debian Wheezy 6.7 / lots of TCP Timed-out

I'm facing a lot of TCP timed-out on a busy cache server and here below my sysctl.conf configuration as well as an output of netstat -st Kernel 3.2.0-4-amd64 #1 SMP Debian 3.2.57-3 x86_64 GNU/Linux ...
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0answers
32 views

Cannot connect to Solaris Server when Oracle GoldenGate process uses the port

I'm trying to test the Oracle goldengate to replicate data between two databases on the same server. So I installed two databases and two goldengate homes in the same machine. The goldengate ...
0
votes
1answer
135 views

iptables and TPROXY support

I'm running iptables v1.4.21 on Ubuntu 14.04 and is trying to setup iptables to use TPROXY. How can I check whether my current build of iptables supports TPROXY? I can check TPROXY support for ...
2
votes
1answer
48 views

remote login failed on windows XP, but remote telnet successful on mac

I recently set up an Oracle DB, started the listener on port 1561, and enabled TCP access. I then opened that port to all incoming connections. When I get on my Mac - I can use telnet remoteserver ...
1
vote
1answer
23 views

TCP rsyslogd events showing up as 2000 character continuations

I'm taking syslog events from a proprietary app. This could be the app's fault or it could be rsyslogd. Events are written like: Aug 15 16:00:00 10.11.12.13 Event1 from this wonderful product using ...
1
vote
2answers
31 views

When a socket switch to TIME_WAIT state, why I can't see its inode number?

I'm developing a program in python that parses /proc/net/tcp informations, but unfortunately, while I was doing this, I saw a strange thing. Practically, when a socket change in TIME_WAIT state, ...
-1
votes
1answer
27 views

CentOS 5.10 TCP Sequence Number

We have done a security check on a server and its come back with Linux Kernel TCP Sequence Number Generation Security Weakness. We are looking to correct this being flagged up on the check We are ...
2
votes
2answers
50 views

Using (r)syslog's dynamic file generation

I am in the middle of configuring a (r)syslog server as a remote server that receives logs from various clients. I wonder whether there is a nicer way to dynamically generate multiple file names as ...
0
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0answers
19 views

Is The MaxUserPort Restriction In Windows Server Accumulative Across All Local IPs?

I have a Windows 2003 server with multiple IPv4 addresses assigned to it. Each single IP address doesn't use more than 2000 outbound sockets/connections. Collectively though across all IPs, this adds ...
-1
votes
1answer
70 views

HAProxy - proxy to webserver via tcp

I have a simple web application, All requests to that application are HTTP based (RESTfull API and standard ajax) I have an haproxy before my tomcat cluster. So now i have clients that http request ...
2
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0answers
127 views

TCP Connection Issue Between Linux Machine and VMWare Windows Server

I have a TCP connection issue as follows. The setup: VMWare Virtual Machine: Windows Server 2008 R2 DataCenter SP1, IP: 192.168.2.111, DG: 192.168.2.254 Host Machine: Windows 7 Professional SP1, IP: ...
0
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1answer
96 views

Troubleshooting High TCP Retransmit Rate

I've been attempting to troubleshoot a network issue that presents with very high rate of TCP retransmits. 36 samples (taken with Wireshark 1.10.8 running on 32-bit Windows 7) totaling a little over ...
0
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3answers
101 views

How does anycast work with tcp?

TCP, being stateful, should require subsequent packets to reach the same server. (Stateless) HTTP runs on top of TCP, and CDN's can use anycast. So how does TCP work with anycast? What if the syn ...
0
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0answers
36 views

FortiBalancer and IE TCP issues

We are using a Fortibalancer for our web servers (Win2012 with IIS) and we have run into a strange issue. IE users will experience timeouts (~77s) in getting a response from our servers. Packet traces ...
1
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2answers
176 views

What is [PSH, ACK] doing during my connection to a global catalog server?

A linux server of mine is trying to establish a LDAPS connection to a global catalog server and the connection is getting dropped (presumably by the GC side). For the purpose of discussion, let's ...