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Questions tagged [keepalive]

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configure inactivity timeout while handling keepalive probes

I am developing a TCP echo server using python and the socket library. I'd like to have a timeout configured for each incoming connection. So to drop and close them if there is inactivity for a ...
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1 vote
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keepalived virtual and real server in different subnets

My goal is to forward the SMTP traffic from one unused server to another using keepalived. The problem is, that the other SMTP server is in different subnet. I have configured keepalive in the ...
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Risks of enabling nginx upstream keepalive

Using nginx as HTTP reverse proxy for Apache with PHP backend (I need .htaccess flexibility for webmasters). Seeing http/1.0 used in Apache logs made me look up on how to enable keep-alive connection. ...
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Is it possible to improve shared-cpu-vps hosting performance with a keep-alive? Or something else?

Taking the leap from dedicated to shared-cpu-vps and have just one major concern: I will no longer have a dedicated CPU. In past tries with vps hosting, I've noticed my servers sometimes don't respond ...
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Keepalived tracking script - Am I able to reduce the time interval to millisecond?

im new here! Ive just set up a cluster which use keepalived to maintain vIP, and haproxy as a loadbalancer proxy. In my keepalived track script configuration, i let keepalived decise the master node ...
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0 votes
1 answer
250 views

Nginx upstream server - client broken connection not timeouting

I have a long poll clients that connect to nginx and upstream to kestrel dot net. Clients have keepalive set that after 2 minutes connection breaks. On nginx side i have listen 0.0.0.0:xxx ssl ...
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  • 115
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1 answer
703 views

keepalived - "notifiy_master"/ "notify_backup" does not start/stop application

I want to start/stop a freeradius depending on the master (start) or the backup (stop) state of the keepalived instance. The freeradius is listening for accounting messages on the shared virtual ip. I ...
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1 vote
1 answer
308 views

nginx detecting dead clients

Normally when you pull the network cable out of a network device (which simulates some drop on the network, so an obscure disconnect), the underlaying sockets do not detect a disconnect (at least our ...
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  • 115
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0 answers
668 views

Keepalived VIP not getting updated MAC after failover

I've got keepalived set up on 2 RHEL7.8 VMs to provide HA for a shared VIP. The VIP works and properly switches to each server when expected. I experience two issues related to the MAC not getting ...
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1 answer
387 views

Apache - Loading is very slow after inactivity. Most states of connections are in K - KeepAlive

I enabled the apache status module, and saw that most of the connections on the apache scoreboard are showing a "K" value. On my server, when I enable KeepAlive, during inactivity it takes a ...
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1 vote
1 answer
738 views

Nginx upstream keepalive with SNI

I've got Nginx setup to proxy two subdomains. SNI is used so each subdomain has a different SSL certificate. Nginx setup is roughly: upstream a_example_443 { server 1.2.3.4:443; keepalive 128; ...
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1 answer
754 views

How to tweak nginx keep-alive settings when you can't guarantee routing to the same host?

I have a scenario where a number of servers are running an nginx instance. For what it's worth, these are mostly just proxied requests. These hosts all sit behind a hardware load balancer and it's not ...
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841 views

Why nginx keepalive_timeout doesn't work?

I have the nginx-server and I need big keepalive_timeout for my api. In nginx.conf I write keepalive_timeout 300; And run apache benchmark test ab -kc 100 -t 30 http://172.16.31.03/ But after ...
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508 views

How to determine if I should use KeepAlive in apache?

I have read several posts and questions about KeepAlive but have not found any suitable for me. I have a server with just one client (Trivago) doing hundreds of (hotel availability) requests per ...
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8 votes
3 answers
14k views

How to disable keepalive in curl

I'm trying to figure out how to consistently turn off keepalive across various client machines which are issuing HTTP requests via curl. This is my target server: - Ubuntu 18.04.2 LTS - 4.15.0-47-...
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2k views

keepalived not promoting BACKUP to MASTER in multi-instance configuration

I'm trying to make a multi-instance keepalived to control a master-replica pair of tarantool servers and setup VIPs. Server state itself is managed outside keepalived. Keepalived should only manage ...
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2 votes
0 answers
238 views

TCP KeepAlives with NAT?

We have a Network set up like this: MQTT Client -- TCP Forward (Netscaler) -- TLS Termination + TCP Forwarding (HAProxy) -- MQTT Server For several reasons we needed to turn on TCP KeepAlives in ...
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  • 171
2 votes
1 answer
3k views

AWS API Gateway with Lambda and KeepAlive (persistent connections)

I'm a bit confused about Keep-Alive with AWS API Gateway. Is this something I need to configure? or maybe be careful with this setting? Because I will use API Gateway to execute Lambda functions, and ...
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4 votes
1 answer
12k views

Difference between keepalive in apache2.conf and in ProxyPass

I am using Apache 2.2.22 What is the difference, if there is any, between the Keepalive directive in /etc/apache2/apache2.conf # # KeepAlive: Whether or not to allow persistent connections (more ...
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2 votes
1 answer
2k views

git push fails - permissions and ssh keep alive checked - what else?

I migrated my git server to a new server and now I try to push my data to the new one. Client: Windows, TortoiseGit Server: docker git-server The log when trying to push git.exe push --progress "...
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  • 201
1 vote
2 answers
1k views

Can TCP Keepalive technique be used to prevent DDOS?

I am learning about DDOS and the techniques to mitigate it. TCP Keepalive is used to check if the other host is still up and if the host does not acknowledge the tcp keep alive message, the connection ...
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0 votes
1 answer
2k views

Apache2,4 + Prefork + Keep-alive On

I'm trying to speed up a website with a lot of images that are served from a separate subdomain static.example.com (same IP as www.) Using the pingdom tool noticed that first 5-6 requests (on static....
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2 answers
4k views

how to emulate a browser that doesn't have "Keep alive"

I have a remote webserver listening on port 80, which serves a page which loads 100 individual .png files (from the same server and hostname) via 100 <img /> tags. On that remote server I do ...
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  • 704
1 vote
1 answer
2k views

Amazon ELB doesn't clean up KeepAlive connections

AWS documentation mentions the following: To ensure that the load balancer is responsible for closing the connections to your instance, make sure that the value you set for the HTTP keep-alive ...
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1 vote
0 answers
685 views

How to make nginx mail auth connection persistent?

We are using nginx 1.7.3 as a reverse proxy for our Mail SMTP service. For authentication of each SMTP connection, we have configured nginx to connect with a http based service for authentication. ...
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1 vote
1 answer
343 views

Apache on Windows occupied by Chrome keep-alive

Chromes keep-alive packets seem to block Apache from answering all requests from other clients. They do not appear in the access log nor in mod_status and the browsers keep waiting for an answer. This ...
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0 votes
1 answer
118 views

Apache delays serving an empty html file while processing a concurrent request

I have a website, which queries a Varnish server, which queries an Apache server, which queries a db server. At 07:00:00, a request is send to the Apache server, which triggers a db request that ...
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1 vote
2 answers
3k views

jenkins cli build via ssh is disconecting after 10 minutes

I have two jenkins instances. I want job at 1st instance to invoke job at 2nd instance, wait until it ends and perform some actions (using artifacts produced by job @ 2nd) I've come up with this ...
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  • 163
2 votes
1 answer
5k views

Why can't Nginx reuse connection to upstream while serving sequential requests from clients?

As mentioned in http://nginx.org/en/docs/http/ngx_http_upstream_module.html#keepalive It should be particularly noted that the keepalive directive does not limit the total number of connections to ...
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693 views

Unable to get Nginx/Apache + FastCGI + PHP-FPM + HTTP/1.0 to use Keep-Alive

For a reason beyond my control (an app that cannot be modified), I need to get a server that processes HTTP requests for PHP pages over FastCGI, to honour "Connection: Keep-alive" (sent by said client)...
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  • 116
1 vote
0 answers
799 views

socket_keepalive configuration for mod_jk

I have Apache httpd with mod_jk. I have issue with killed connections after long idling period: Apache stops to respond and each HTTP request hangs for 15 minutes. I tried turn off mod_jk connection ...
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2 votes
1 answer
1k views

Linux GRE keep alive

What are possibilities in Linux kernel (?) to work with Cisco endpoint encorporating GRE keep-alives? We have GRE IPsec tunnel set up with another company. We would like to have backup tunnel which ...
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2 votes
2 answers
3k views

KeepAlive in Apache 2.4 interfering with form submissions

I have just upgraded a server to Debian Jessie, which includes Apache 2.4.10 (was 2.2), and PHP 5.6. Now, SSL sites won't submit forms in some circumstances on IE11 and iPad Safari (not sure about ...
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1 vote
2 answers
2k views

Keeping TCP connections alive to track which clients are online

I am developing an application where a server needs to stay in touch with lots of simple IoT devices. Nearly no information exchange is needed between the server and each device, but devices need to ...
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0 votes
1 answer
992 views

TCP Keepalive: Why does an idled ESTABLISHED connection end after 60 seconds, instead of tcp_keepalive_time?

I am investigating ways to mitigate a server against DoS-type attacks. In one scenario, I've opened several hundred TCP connections to my webserver. I do not send any data after the initial TCP ...
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0 votes
1 answer
332 views

WebSphere breaks connection while servlet continues to work

We have an application running on WebSphere. Requests are often running for a long time (tens of minutes). Our users report that Internet Explorer breaks connection and shows blank screen after some ...
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1 vote
1 answer
1k views

Keepalived + Haproxy performance, apache or nginx? [duplicate]

I have a question about Keepalived + Haproxy. At work I am assigned to deploy a redundant web server with Keepalived and Haproxy. Our setup at the moment is as follows: Apache (as load balancer) + ...
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6 votes
2 answers
2k views

(Why) does FreeBSD 'net.inet.tcp.always_keepalive' violate RFC1122?

While working on a server application that runs on FreeBSD and uses TCP, I noticed that TCP keepalive probes get sent even though my application explicitly disables SO_KEEPALIVE on TCP sockets. ...
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2 votes
0 answers
12k views

HAProxy resetting backend connections

I'm in the process of setting up a series of servers as proxies to our application server, primarily to obscure the application server's IP as part of a suite of anti-DDOS measures. My goal is to ...
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3 votes
0 answers
2k views

Keepalive best practices for Nginx-Haproxy-Apache chain

I am using Nginx to serve static content, and Haproxy to proxy requests to multiple Apache2 backends discovered via Zookeeper. Nginx -> Haproxy -> Apache2 According to the official Nginx website, it ...
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3 votes
1 answer
3k views

How does apache handles connections and requests using worker and prefork mpm modules?

I know that prefork module in apache creates one master process and several child processes to handle connections, my question is: Does each prefork child handles one connection or handles one ...
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0 votes
1 answer
1k views

Configure Server to Initiate Http Keep-Alive

I have a set of clients that aren't including an http keep-alive header in their requests to my server. If I use something like Varnish to filter the incoming requests and add the keep-alive header ...
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11 votes
1 answer
34k views

Haproxy - timeout http-request vs timeout http-keep-alive vs timeout server

I'm trying to wrap my head around how the haproxy options timeout http-request <timeout> timeout http-keep-alive <timeout> timeout server <timeout> interact with each other. I'm ...
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  • 245
-1 votes
1 answer
860 views

HTTP connection keepalive logic [closed]

I am fairly new to HTTP and pardon me if the question looks stupid. I cant get my head around the HTTP keepalive logic. I am studying HTTP definitive guide. We send multiple requests , response over ...
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4 votes
1 answer
8k 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. server.max-...
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  • 171
1 vote
0 answers
754 views

How to force/fake linux eth0 in 'up' status even without cable connected?

One of my testing script is eth0 status related, when eth0 goes down(cable unplugged), the script exit, and i need to unplug and plug cable many times due to test needs. is there anyway can fake ...
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  • 163
4 votes
1 answer
3k views

Tuning Apache KeepAlive Timeout for HTTPS

My website forces HTTPS everywhere and has an average first load time of 3-5 seconds. Thanks to caching, repeat load time is 0.8 seconds. The SSL negotiation takes 150-300ms on my server, so I want ...
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23 votes
3 answers
47k views

nginx connection timeout & client closed connection issue

I have this nginx server running on AWS & it was working all fine until recently when couple of users started complaining about the website not opening until they made some 10 attempts to access ...
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3 votes
1 answer
8k views

option http-server-close on HAProxy haproxy-1.5-dev19 will result in Connection: close header sent in response

I basically have the following issue: whenever I add option http-server-close to the haproxy config (either in frontend or backend section), haproxy will send a Connection: close header in the ...
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0 votes
3 answers
3k views

Which settings schould be changed to lower apache CPU usage and use more RAM?

On our CentOS 6 server, we have now a lot of CPU overload, while our RAM is almost not used. KeepAlive is set to "on" because we have some AJAX elements on your website and serving many files such as ...
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