# No TCP ACK on first client request

**URL:** https://discourse.haproxy.org/t/no-tcp-ack-on-first-client-request/2430
**Category:** Help!
**Created:** [April 27, 2018, 9:26pm UTC](https://discourse.haproxy.org/t/no-tcp-ack-on-first-client-request/2430 "2018-04-27T21:26:09Z")
**Posts on this page:** 5
**Page:** 1

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### Author: ![verdel](https://avatars.discourse-cdn.com/v4/letter/v/db5fbb/32.png) [@verdel](https://discourse.haproxy.org/u/verdel)
#### Post date: [April 27, 2018, 9:26pm UTC](https://discourse.haproxy.org/t/no-tcp-ack-on-first-client-request/2430/1 "2018-04-27T21:26:09Z")

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Hello. I have HA-Proxy version 1.8.7.  
I use curl --with-negotiate -x [http://haproxy:3128](http://haproxy:3128) [http://gov.ru](http://gov.ru) as client and Squid proxy as backend.

With haproxy i see this:

 ![image](https://us1.discourse-cdn.com/flex016/uploads/haproxy/original/1X/6dbd37dfaa2203ccffbfc6860cd0b3912ba27303.png)

Why there is no TCP ACK packet between HEAD and HTTP with 407 code? Why haproxy don’t send TCP ACK on first client request?

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### Author: ![lukastribus](https://avatars.discourse-cdn.com/v4/letter/l/7ea924/32.png) [@lukastribus](https://discourse.haproxy.org/u/lukastribus)
#### Post date: [April 28, 2018, 12:27pm UTC](https://discourse.haproxy.org/t/no-tcp-ack-on-first-client-request/2430/2 "2018-04-28T12:27:54Z")

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Frame 5 probably ACKs frame 4. The wireshark per frame summary line is certainly not enough to understand this. Click on the frame, and open the TCP details of those specific packets.

That being said, haproxy does not manage the ACKs, your Operating System/kernel does.

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### Author: ![verdel](https://avatars.discourse-cdn.com/v4/letter/v/db5fbb/32.png) [@verdel](https://discourse.haproxy.org/u/verdel)
#### Post date: [April 28, 2018, 3:37pm UTC](https://discourse.haproxy.org/t/no-tcp-ack-on-first-client-request/2430/3 "2018-04-28T15:37:21Z")

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This pcap dump file of traffic without HAProxy  
[https://yadi.sk/d/mQ1us1SD3UtM5b](https://yadi.sk/d/mQ1us1SD3UtM5b)

And this of traffic through HAProxy  
[https://yadi.sk/d/Ah9hrgxb3UtMJx](https://yadi.sk/d/Ah9hrgxb3UtMJx)

WIthout HAProxy there is empty TCP packet with ACK flag from server to client after TCP with first get

 ![image](https://us1.discourse-cdn.com/flex016/uploads/haproxy/original/1X/f58ccfbc54cd49bbdd92678b83c849c5db8ba7ae.png)

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### Author: ![verdel](https://avatars.discourse-cdn.com/v4/letter/v/db5fbb/32.png) [@verdel](https://discourse.haproxy.org/u/verdel)
#### Post date: [April 28, 2018, 3:37pm UTC](https://discourse.haproxy.org/t/no-tcp-ack-on-first-client-request/2430/4 "2018-04-28T15:37:58Z")

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And with HAProxy this TCP packet absent

 ![image](https://us1.discourse-cdn.com/flex016/uploads/haproxy/original/1X/33e9d531c798cf9a9ca963c2121ddebcaf1e6d93.png)

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### Author: ![lukastribus](https://avatars.discourse-cdn.com/v4/letter/l/7ea924/32.png) [@lukastribus](https://discourse.haproxy.org/u/lukastribus)
#### Post date: [April 28, 2018, 4:01pm UTC](https://discourse.haproxy.org/t/no-tcp-ack-on-first-client-request/2430/5 "2018-04-28T16:01:53Z")

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What I said: Frame 5 is ACKing Frame 4.

Just open frame 5, TCP and then go to SEQ/ACK analysis.