# Can we add feature without compilation

**URL:** <https://discourse.haproxy.org/t/can-we-add-feature-without-compilation/7031>\
**Category:** Help!\
**Created:** [October 27, 2021, 4:07pm UTC](https://discourse.haproxy.org/t/can-we-add-feature-without-compilation/7031 "2021-10-27T16:07:13Z")\
**Posts on this page:** 9\
**Page:** 1

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**Author:** ![mho](https://avatars.discourse-cdn.com/v4/letter/m/a183cd/32.png) [@mho](https://discourse.haproxy.org/u/mho)\
**Post date:** [October 27, 2021, 4:07pm UTC](https://discourse.haproxy.org/t/can-we-add-feature-without-compilation/7031/1 "2021-10-27T16:07:13Z")

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Hello,  
i would like to understand what is the ‘Feature list’ in haproxy -vv output cmd.

if i have + or -  
Feature list : +EPOLL -KQUEUE +NETFILTER -PCRE -PCRE\_JIT -PCRE2 -…

Could i add feature without recompiling?

Thanks.

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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:** [October 27, 2021, 7:32pm UTC](https://discourse.haproxy.org/t/can-we-add-feature-without-compilation/7031/2 "2021-10-27T19:32:19Z")

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`+` means you have it, `-` means you don’t.

> [@mho](#):
>
> Could i add feature without recompiling?

No.

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<div class="post-metadata">

**Author:** ![mho](https://avatars.discourse-cdn.com/v4/letter/m/a183cd/32.png) [@mho](https://discourse.haproxy.org/u/mho)\
**Post date:** [October 28, 2021, 8:17am UTC](https://discourse.haproxy.org/t/can-we-add-feature-without-compilation/7031/3 "2021-10-28T08:17:03Z")

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Thanks,  
I have Ubuntu Server 20.04 with default repos, i installed with apt haproxy, i would like to add feature, can i compile the same version and retrieve the compiled module to insert in haproxy?

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<div class="post-metadata">

**Author:** ![lukastribus](https://avatars.discourse-cdn.com/v4/letter/l/7ea924/32.png) [@lukastribus](https://discourse.haproxy.org/u/lukastribus)\
**Post date:** [October 28, 2021, 3:58pm UTC](https://discourse.haproxy.org/t/can-we-add-feature-without-compilation/7031/4 "2021-10-28T15:58:03Z")

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What feature you think you need that is not present in the Ubuntu repository build?

> [@mho](#):
>
> can i compile the same version and retrieve the compiled module to insert in haproxy?

No, haproxy doesn’t support modules.

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<div class="post-metadata">

**Author:** ![mho](https://avatars.discourse-cdn.com/v4/letter/m/a183cd/32.png) [@mho](https://discourse.haproxy.org/u/mho)\
**Post date:** [October 28, 2021, 8:07pm UTC](https://discourse.haproxy.org/t/can-we-add-feature-without-compilation/7031/5 "2021-10-28T20:07:40Z")

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> [@lukastribus](#):
>
> feature you think you need that is not present in the Ubuntu repository build?

I need tproxy, i am behind NAT and i want to control tcp connection ip address

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<div class="post-metadata">

**Author:** ![lukastribus](https://avatars.discourse-cdn.com/v4/letter/l/7ea924/32.png) [@lukastribus](https://discourse.haproxy.org/u/lukastribus)\
**Post date:** [October 28, 2021, 8:27pm UTC](https://discourse.haproxy.org/t/can-we-add-feature-without-compilation/7031/6 "2021-10-28T20:27:52Z")

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> [@mho](#):
>
> I need tproxy

I just installed haproxy on Ubuntu 20.04 and it installs `2.0.13-2ubuntu0.3 2021/08/27` which supports it out of the box:

```
Feature list : [...] +TPROXY +LINUX_TPROXY [...] 

```

Is that not the case for you? Can you share your FULL output of `haproxy -vv`?

> [@mho](#):
>
> i am behind NAT and i want to control tcp connection ip address

tproxy will require some dirty tricks with ip forwarding, putting haproxy in your lan as a default-gateway for the backend server, etc.

It’s a complex configuration. Are you sure you exhausted all other possibilities, like the proxy protocol, X-F-F headers and the like?

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<div class="post-metadata">

**Author:** ![mho](https://avatars.discourse-cdn.com/v4/letter/m/a183cd/32.png) [@mho](https://discourse.haproxy.org/u/mho)\
**Post date:** [November 1, 2021, 8:45am UTC](https://discourse.haproxy.org/t/can-we-add-feature-without-compilation/7031/8 "2021-11-01T08:45:57Z")

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XFF http only, send-proxy require backend to support it.  
There are others possibilties ?

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<div class="post-metadata">

**Author:** ![lukastribus](https://avatars.discourse-cdn.com/v4/letter/l/7ea924/32.png) [@lukastribus](https://discourse.haproxy.org/u/lukastribus)\
**Post date:** [November 1, 2021, 9:13am UTC](https://discourse.haproxy.org/t/can-we-add-feature-without-compilation/7031/9 "2021-11-01T09:13:55Z")

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No, thats it. But for Tproxy you need to change your network configuration, and put the haproxy instance in there as a default-gateway. It’s not a trivial configuration.

Anyway, the haproxy build shipped with Ubuntu supports tproxy just fine as per my earlier post.

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<div class="post-metadata">

**Author:** ![mho](https://avatars.discourse-cdn.com/v4/letter/m/a183cd/32.png) [@mho](https://discourse.haproxy.org/u/mho)\
**Post date:** [November 1, 2021, 3:43pm UTC](https://discourse.haproxy.org/t/can-we-add-feature-without-compilation/7031/10 "2021-11-01T15:43:54Z")

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Thanks, i seen,  
thanks for your help.