# Nginx routing based on ip address

**URL:** <https://www.ruby-forum.com/t/nginx-routing-based-on-ip-address/244125>\
**Category:** NGINX\
**Created:** [February 24, 2016, 6:26am UTC](https://www.ruby-forum.com/t/nginx-routing-based-on-ip-address/244125 "2016-02-24T06:26:54Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Sadaf\_N](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/858c86/32.png) [@Sadaf\_N](https://www.ruby-forum.com/u/Sadaf_N)\
**Post date:** [February 24, 2016, 6:26am UTC](https://www.ruby-forum.com/t/nginx-routing-based-on-ip-address/244125/1 "2016-02-24T06:26:54Z")

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I am wondering if it is possible to compute some kind of hash value from  
ip  
address or do modulo operation on the last numeric value from ip address  
(for example on 24 given 172.16.4.24)? Based on this, I want to send the  
request to different endpoints (not to different servers). If this can  
be  
done without installing any new module, that would be the best.

As far as I can see, I feel like I should do something similar using the  
regex?

Posted at Nginx Forum:

> **[nginx routing based on ip address](https://forum.nginx.org/read.php?2,264742,264742#msg-264742)**
>
> I am wondering if it is possible to compute some kind of hash value from ip address or do modulo operation on the last numeric value from ip address (for example on 24 given 172.16.4.24)? Based on this, I want to send the request to different...

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**Author:** ![keeyong](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/f19dbf/32.png) [@keeyong](https://www.ruby-forum.com/u/keeyong)\
**Post date:** [February 24, 2016, 6:49pm UTC](https://www.ruby-forum.com/t/nginx-routing-based-on-ip-address/244125/2 "2016-02-24T18:49:59Z")

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## keeyong Wrote:

> I am wondering if it is possible to compute some kind of hash value  
> from ip address or do modulo operation on the last numeric value from  
> ip address (for example on 24 given 172.16.4.24)? Based on this, I  
> want to send the request to different endpoints (not to different  
> servers). If this can be done without installing any new module, that  
> would be the best.
> 
> As far as I can see, I feel like I should do something similar using  
> the regex?

Yes, regex and map should help. If you want to derive four distinct  
values,  
you can do something like this:

map $remote\_addr $key {  
~.[0-9]$ 1; # 0..9  
~.[0-5][0-9]$ 1; # 10..59  
~.6[0-4]$ 1; # 60..64  
~.6[5-9]$ 2; # 65..69  
~.[7-9][0-9]$ 2; # 70..99  
~.1[0-1][0-9]$ 2; # 100..119  
~.12[0-8]$ 2; # 120..128  
~.129$ 3; # 129  
~.1[3-8][0-9]$ 3; # 130..189  
~.19[0-2]$ 3; # 190..192  
default 4;  
}

Caveats: This does not work for IPv6.

I have no idea if the fourth IP byte is normally distributed. If not,  
then  
may generate a full mapping (~.1$, ~.2$, … ~.10$, …, ~.99$, ..,  
~.255$)

If you want to do something even more fancy you can go totally binary  
with  
the $binary\_remote\_addr variable and \xYY in the regexp (never tried  
this as  
it is more difficult to debug).

Oliver

Posted at Nginx Forum:  
[https://forum.nginx.org/read.php?2,264742,264786#msg-264786](https://forum.nginx.org/read.php?2,264742,264786#msg-264786)