# Asterisk behind NAT and clients behind NAT

**URL:** <https://community.asterisk.org/t/asterisk-behind-nat-and-clients-behind-nat/49340>\
**Category:** Asterisk Support\
**Created:** [July 26, 2015, 12:37pm UTC](https://community.asterisk.org/t/asterisk-behind-nat-and-clients-behind-nat/49340 "2015-07-26T12:37:30Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![pranahata](https://avatars.discourse-cdn.com/v4/letter/p/cab0a1/32.png) [@pranahata](https://community.asterisk.org/u/pranahata)\
**Post date:** [July 26, 2015, 12:37pm UTC](https://community.asterisk.org/t/asterisk-behind-nat-and-clients-behind-nat/49340/1 "2015-07-26T12:37:30Z")

</div>

Hi,

We just install asterisk on a Centos 6 vm and it is sitting behind a firewall (ads router) here at office 1.

We can connect Xlite to asterisk from any computers in office 1.

Office 2 is also behind a firewall (another adsl router) but we can’t connect Xlite to the asterisk server in office 1.

On sip.conf we have

`[general]
context=public ; Default context for incoming calls. Defaults to 'default'
externhost=pablo.anahata.uno ; refreshed periodically
externrefresh=180
nat=yes
localnet=10.1.1.0/255.255.255.0
qualify=yes
`

and then…

[code][pablo\_laptop]  
type=friend  
context=phones  
host=dynamic  
secret=Anahata123

[pablo\_desktop]  
type=friend  
context=phones  
host=dynamic  
secret=Anahata123

[cisco\_7940]  
type=friend  
context=phones  
host=dynamic  
secret=Anahata123

[cisco\_7941]  
type=friend  
context=phones  
host=dynamic  
secret=Anahata123

[arslan\_desktop]  
type=friend  
context=phones  
host=dynamic  
secret=Anahata123  
[/code]

on rtp.conf we have:

`[general]
;
; RTP start and RTP end configure start and end addresses
;
; Defaults are rtpstart=5000 and rtpend=31000
;
rtpstart=10000
rtpend=20000
`

In office 1 firewall, we have forwarded 5060 tcp/udp and 10000-20000 udp to the asterisk server as per this image  
[postimg.org/image/yljih73v1/](http://postimg.org/image/yljih73v1/)

Does anyone know why the sip soft phones (e.g. XLite) in office 2 cannot connect to asterisk on office 1?

Thanks