netstat is a tool for viewing active network connections, listeners and sockets.

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Netstat showing multiple connections for on ssh login

I connect to my server via ssh. I am the only person who has access to connect to the server. After connecting via ssh, I run the following command: sudo netstat -tupn The output includes the ...
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3answers
274 views

Is postfix the only program that should be using port 25

My server IP was blacklisted for sending out spam and I am tracking down the program sending spam. I did netstat, and it shows a lot of programs using port 25 e.g tcp 0 182 ...
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33 views

Synology open for Cloud Station even if blocking 6690 port

I have a NAS Synology beyong my Internet Box. On the Internet Box, I have UPnP not activated and I have only activated on Port Transfer the following ports : 1701/TCP, 500/TCP and 4500/TCP which are ...
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18 views

What exactly constitutes a bad TCP segment?

What constitutes a bad segment as in bad segments received in the netstat output below? I would think a TCP header's checksum could do it, but are there other things? If a segment arrives after its ...
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1answer
189 views

lsof doesn't show the established TCP connection

On my system, if I run the netstat for a port, it returns: $ netstat -nat | grep "60964" tcp 0 0 192.0.0.1:60964 0.0.0.0:* LISTEN tcp 59 0 ...
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49 views

Is it possible to deterministically trace how port 80 is forwarded and where the configuration is on a given system?

Is there a way to determine or trace how a port forwarding configuration is set up on a system running Ubuntu 14.04 LTS, on which there is a NodeJS service running and somehow accepting connections ...
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1answer
32 views

Does the netstat counter wrap around? And over what period are they collected?

If I run netstat -s on my solaris 10 box, I got a lot of network statistics. Are these counters since the time of system boot, or some other arbitrary period? And some of the numbers are quite ...
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67 views

SSH Tunnel not working

I have a number of SSH tunnels set up between our company's server (hosts website) and our customer's servers (hosts database). For all sites but one the connection is relatively stable however one ...
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1answer
51 views

How to use non-deprecated tools like ss to get process id running on a port?

I am looking for a non-deprecated way of running a command like netstat -tulpn | grep 8000 to output information about an active port. Any suggestions on how to use a tool like ss to get the process ...
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1answer
80 views

Too large 127.0.0.1 connections with nginx - apache2 [duplicate]

I use nginx as proxy-server apache2 and I have a problem with netstat output: $ netstat -ntu | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n 5 109.195.36.169 6 109.195.33.205 8 ...
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125 views

Does “ESTABLISHED” state in netstat command for the sshd program mean they actually have access?

I have this person(or bot) from an IP in Chile which has an "ESTABLISHED" connection to SSHD as root on my server. I'm trying to understand what netstat's outputs really mean, the manual doesn't ...
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2answers
36 views

See stats of data in and out of each connection to a port

I have an application listening to a port. The clients connect to it using http connection. At any given time I see around 3000 connections established. I assume not all these connections are in use ...
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1answer
28 views

Concurrent connections per IP

I need to make a few changes to a firewall configuration, but before I do I'd like to see the number of concurrent Apache connections per IP. This command produces a nice list: #netstat -ntu | awk ...
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2answers
66 views

Print last column containing spaces and special characters

I need a full path/command thats been execued to start a process thats exposed on the network - listens on tcp/udp . I did manage to get all of that using below "one liner": netstat -nlp46|tail -n +3 ...
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1answer
157 views

Is it normal to have many connections from my own server ip when I ran netstat command?

I would like to know if is it normal to have many connections from my own server ip when I ran: netstat -tn 2>/dev/null | grep :80 | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -nr | ...
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0answers
78 views

Why is SQL Server using all ephemeral ports connecting to itself and causing TIME_WAITs?

I've got an AWS server with Windows 2008 R2, SQL Server 2012, and Tomcat 7. When I run netstat -ano the screen is flooded with TIME_WAIT. I posted the output in a Gist. When I run CurrPorts, filter ...
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150 views

TCP High Send-q coupled with FIN_WAIT1 status

I'm having a problem with one of my webservers, which is taking minutes to completely render a web page. I had a look at the TCP connection and noticed that I have a very high value in the send-q ...
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120 views

No connection available in pool. netstat RecvQ shows high number

In our servers there is one particular dependency (java jar), which makes a total of 1024 connection to various remote servers (the library works as a service discovery). Intermittently, it is ...
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1answer
887 views

Nginx not running with no error message (ubuntu 14.04 lts)

I am trying to start my nginx server. When I type "$> /etc/init.d/nginx start", I have a message appearing "Starting nginx: Ok", and then nothing happens. When I type "sudo lsof -nP -i | grep ...
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2answers
1k views

How to make netstat on Linux only show OUTBOUND tcp connections?

My ubuntu server is infected and there is a process making a bunch of HTTP requests to a bunch of websites (sucks!). I have added the following to my firewall (UFW): sudo ufw deny out proto tcp to ...
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31 views

netstat output without PID

I just stumbled across this issue with the netstat output on my server, There are a couple of ports which are listening, but do not have a PID attached to it. I want to make sure they are not ...
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1answer
233 views

Port suddenly closed. How to re-open?

I've written a software module in PHP that manages the saving of data in different data stores (MySQL, ElasticSearch and Redis). To test the module, I've created several test plans in Apache JMeter, ...
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2answers
122 views

Limit to number of listening ports in linux

I have tried to launch a script to listen to thousands of tcp ports (1000 to 10000) but it appears to be hitting a limit of 1024 listening ports. I've confirmed this via netstat and closed ports above ...
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43 views

How to check a given connection has been offloaded to network card

From what I read, some part of the tcp protocol operation can be offloaded from kernel to network card driver thanks to TOE (or GSO, LSO, LRO..). My objective is too find if a given socket has some ...
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63 views

Simulation of TX/RX Drop

I'm trying to get the "TX/RX Drop" values to increase. I've tried dropping packets using both iperf and iptables but the statistics aren't increasing even when packets are being dropped. Is there a ...
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86 views

iptables traffic after forwarding

I have 2 servers Server A and Server B ServerA = 1.1.1.1 ServerB = 2.2.2.2 I am using ip-tables to send all traffic on port 80 to Server B on Server (A) 1.1.1.1 i have done iptables -t nat -A ...
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111 views

Ghost tcp connections: ss sees them, nothing else does

We have a strange problem. Our remote server shows over 900 connections coming from our office over port 80: # ss -n | grep ESTAB | grep $OFFICEIP | grep :80 | wc -l 935 Netstat shows a similar ...
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2answers
161 views

Display IP & TCP statistics per interface (netstat -s with interface)

Linux has the ability to display protocol statistics with netstat -s. The output looks something like: Excerpt: 7487 times unabled to send RST due to no memory TCPDSACKIgnoredOld: 817 ...
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1answer
154 views

Limit Number of TCP connections in Linux Server, to avoid attack

I want to limit the number of TCP connections in Linux server, I have used the following command. iptables -A INPUT -p tcp --syn --dport 80 -m connlimit --connlimit-above 25 --connlimit-mask 32 ...
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1answer
109 views

Port 80 doesn't work

I have a website in my ubuntu server 14.04, with apache2 server, and untils fews days go the site works fine but, today if I digit www.mydomain.com from my internal network it works but, if I try with ...
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5answers
311 views

Get number of TCP established connections

On a Linux server one can use netstat -tan | grep ESTABLISHED| wc -l but this will not work on a high load server with watch -n1. Such approach works fine if the server is not very busy or the ...
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328 views

What causes “SYN to LISTEN sockets dropped”?

A quite busy proxy server has lots of "SYNs to LISTEN sockets dropped". I learned one cause could be a too small backlog size. But in that case the "times the listen queue of a socket overflowed" ...
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88 views

xinetd stops working in Debian Wheezy

We have a server with a whois service running. The whois service is provided by xinetd. The configuration file /etc/xinetd.d/whois looks like this: service whois { socket_type = stream ...
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4answers
297 views

Is there a netstat -s equivalent for windows?

I know that netstat -s exists on Windows, but it displays way less informations than on Linux/OS X. It only gives 8 counters about TCP, while on Linux it's more than 50. I'm looking for any ...
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1answer
206 views

What does it mean for netstat -t

I see the help of netstat -t option says Displays the current connection offload state. And I tried it in the windows command console. The Offload State value display InHost. What does Offload ...
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2answers
786 views

Netstat count TIME_WAIT connections by port

I can obtain individual TIME_WAIT counts on a port, netstat -nat | grep :11300 | grep TIME_WAIT | wc -l; but how to do this based on all ports eg: 11300 2900 connection 3306 1200 connection ...
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130 views

netstat e on windows shows really high bytes count

running netstat /e is giving me strange results "bytes received" from netstat /e output is always way higher, about 10 times higher than when netsh interface ip show subinterfaces is run. wireshark ...
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3k views

Windows TCP Port 139 Netbios-ssn vulnerability

I ran netstat -b on my computer. Two results showed that I do not understand, VAIO being another PC on the LAN. [firefox.exe] TCP 192.168.100.106:49186 VAIO:netbios-ssn TIME_WAIT TCP ...
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2answers
108 views

Difference Between Netstat and Access Log

When I was checking stats in SSH terminal for my VPS, I noticed that netstat and access log gives different results. When I used: netstat -anp I saw that one attacker having 32 concurrent ...
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1answer
101 views

there is empty ips in netstat

I have installed ddos deflate on my sever (centos6.5 64bit) and in server mailbox I see that ddos deflate has been blacklisted empty Ip. and when I run this command on ssh I see: netstat -ntu | awk ...
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2answers
266 views

After kill -9 process won't disappear and port is still bound

We have a Java server application running on Mac OS X. Occasionally this application has become unresponsive, and we have resorted to killing it with kill -9. However, the process doesn't disappear; ...
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397 views

What are records in 'netstat' command are when using logstash?

I use logstash with embedded elasticsearch. My logstash config looks like the following: output { tdout { debug => true debug_format => "json"} elasticsearch { embedded => true ...
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2answers
162 views

How to find the count of Apache workers' at a given point for shared IPs?

One can find the number of Apache workers an IP address is consuming at an instantaneous point in time by executing: netstat -pantu | grep :80 |sort | uniq -c |grep <IP_HERE, eg: 192.168> | wc ...
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2answers
261 views

Can I find the list of ports being listened by a process ordered by the time of opening?

I know I can see the list of open ports using the lsof command. I am trying to view the results ordered by timestamp of listening. The process opens multiple (~6) ports and I suspect the order of ...
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How to get the number of current connections to an external web service [closed]

My application makes many requests in a day to a webservice (say 172.20.20.20:11111) on a different server. I would like to know how I can count the number of connections that are established (the ...
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2answers
186 views

netstat brought up strange ip

I just ran netstat -vatn and found there was a connection ESTABLISHED on :22 from my ip and another unknown ip. Moments later I ran it again and found the connection was gone. I have a default ...
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517 views

What does “connections reset due to unexpected data” in netstat -s mean

I'm running a memcached server under heavy load from multiple web servers. While investigating some odd app level behaviour, we spotted that netstat -s on the memcached box was showing a lot of ...
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1answer
1k views

Netstat hangs: why?

Sometimes (not too often at all) when I type "netstat", it takes over 5 seconds to return. While other times is instantaneous. I have been observing this for weeks on my server (CentOS 6.4), but I ...
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2answers
2k views

How does netstat get a hostname from IP while nslookup & nblookup fail every time?

In Windows Server 2003, when I run netstat with no flags, it takes much longer than netstat -n to return results. I realize this is because it has to perform reverse lookups by IP address to get the ...
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1answer
724 views

Lots of TIME_WAIT from same IP address

I've seen a lot of questions with people concerned about lots of TIME_WAITs in netstat. I'm having a similar problem but all the TIME_WAITs are coming from the same IP address. I get over 200 of the ...