# Loopback configure of EM9293 and EM7431

**URL:** <https://forum.sierrawireless.com/t/loopback-configure-of-em9293-and-em7431/35026>\
**Category:** Uncategorized\
**Created:** [June 4, 2025, 6:14am UTC](https://forum.sierrawireless.com/t/loopback-configure-of-em9293-and-em7431/35026 "2025-06-04T06:14:50Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![shanywu](https://avatars.discourse-cdn.com/v4/letter/s/e79b87/32.png) [@shanywu](https://forum.sierrawireless.com/u/shanywu)\
**Post date:** [June 4, 2025, 6:14am UTC](https://forum.sierrawireless.com/t/loopback-configure-of-em9293-and-em7431/35026/1 "2025-06-04T06:14:50Z")

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I use AT command “AT!DATALOOPBACK” to enable EM9293 or EM7431 loopback mode and then use “AT!DATALOOPBACK?” to check the loopback status, the loopback is enable, next the host use interface “wwan0” to send packet to modem, but the host cannot receive packet from modem, how do I to set loopback mode of modem?

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**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\
**Post date:** [June 4, 2025, 7:12am UTC](https://forum.sierrawireless.com/t/loopback-configure-of-em9293-and-em7431/35026/2 "2025-06-04T07:12:28Z")

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what did you see ifconfig now?

e.g.

1. . Make sure the IP is existed; to check the ipconfig from CMD:

(IP for LOOPBACK should be 192.168.48.171)

(GW for LOOPBACK should be 192.168.48.172)

1. Measure the throughput using iperf commands:

iperf.exe -s -u -i1 -p5001

iperf.exe -c 192.168.48.172 -u -b10M -i1 -t10 -p5001

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<div class="post-metadata">

**Author:** ![shanywu](https://avatars.discourse-cdn.com/v4/letter/s/e79b87/32.png) [@shanywu](https://forum.sierrawireless.com/u/shanywu)\
**Post date:** [June 4, 2025, 7:44am UTC](https://forum.sierrawireless.com/t/loopback-configure-of-em9293-and-em7431/35026/3 "2025-06-04T07:44:36Z")

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I didn’t set IP for wwan0, I only enable modem loopback and send packets by wwan0, so do I need to set wwan0’s IP as 192.168.48.171?

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<div class="post-metadata">

**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\
**Post date:** [June 4, 2025, 7:47am UTC](https://forum.sierrawireless.com/t/loopback-configure-of-em9293-and-em7431/35026/4 "2025-06-04T07:47:12Z")

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yes, i think so, you can first test like this