# 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:** 3

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**Author:** ![Epyon](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/epyon/32/8479_2.png) [@Epyon](https://www.thethingsnetwork.org/forum/u/Epyon)\
**Post date:** [January 23, 2017, 10:19pm UTC](https://www.thethingsnetwork.org/forum/t/udp-ports-and-firewalling/4995/3 "2017-01-23T22:19:46Z")

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So if I understand correctly: the client (gateway) sends UDP packets from a random client side port to server side port 1700 of the TTN server, and the server sends from server side port 1700 back to the previously used random client port on the client (gateway) side?

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