# UDP ports and firewalling

**URL:** <https://www.thethingsnetwork.org/forum/t/udp-ports-and-firewalling/4995>\
**Category:** TTN Network and Services\
**Created:** [January 23, 2017, 4:34pm UTC](https://www.thethingsnetwork.org/forum/t/udp-ports-and-firewalling/4995 "2017-01-23T16:34:59Z")\
**Posts on this page:** 1\
**Showing post:** 9

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**Author:** ![kersing](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/kersing/32/44777_2.png) [@kersing](https://www.thethingsnetwork.org/forum/u/kersing)\
**Post date:** [January 28, 2017, 10:19pm UTC](https://www.thethingsnetwork.org/forum/t/udp-ports-and-firewalling/4995/9 "2017-01-28T22:19:55Z")

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> [@Epyon](#):
>
> But still strange that the gateway doesn’t initiate push\_ack when at work

Push ack is the response from TTN, it looks like all return traffic is (still) being blocked by some firewall.

> [@arjanvanb](#):
>
> Instead, it seems it only changes targets ports for PULL\_RESP when receiving a PULL\_DATA message, not when receiving other packets such as an uplink or statistics

Confirmed: The PULL packets use one UDP ‘connection’ and the PUSH (data and statistics) use another. Both ‘connections’ have their own originating ports and the back-end replies to the port associated with the connection.

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