# Questions on underlying port restrictions in nccl/gloo communication

**URL:** <https://discuss.pytorch.org/t/questions-on-underlying-port-restrictions-in-nccl-gloo-communication/171573>\
**Category:** distributed\
**Created:** [February 1, 2023, 3:57pm UTC](https://discuss.pytorch.org/t/questions-on-underlying-port-restrictions-in-nccl-gloo-communication/171573 "2023-02-01T15:57:03Z")\
**Posts on this page:** 1\
**Showing post:** 17

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**Author:** ![kwen2501](https://discuss.pytorch.org/user_avatar/discuss.pytorch.org/kwen2501/32/48844_2.png) [@kwen2501](https://discuss.pytorch.org/u/kwen2501)\
**Post date:** [February 16, 2023, 1:28am UTC](https://discuss.pytorch.org/t/questions-on-underlying-port-restrictions-in-nccl-gloo-communication/171573/17 "2023-02-16T01:28:49Z")

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> [@Fei\_Liu](#):
>
> ```auto
> misc/socket.cc:191 NCCL WARN Net : No interface found in the same subnet as remote address ip0:<npt>
> 
> ```

This issue may be that host 1 is not in the same subnet as the IP address specified in `NCCL_COMM_ID`. It is not about the port specified in `NCCL_COMM_ID`.

For example, if host 0 is in subnet 192.168.1.xx, and host 1 is in subnet 10.0.1.xx, this won’t work.

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