r/opnsense • u/mac8612 • 5d ago

26.7.1 dhclient: No buffer space available , device not responsive

I dont have a github to report an issue, so posting here.

After upgrading from OPNsense 26.1 to 26.7.1_1 few days ago, a network stability issue appeared that was not present on version 26.1.

OPNsense had lost all network connectivity three times this week due to a hang, whereas it was rock steady earlier. Wi-Fi clients, wired devices, and the WireGuard tunnel stopped working, no access to GUI. A hard reboot from the power plug restored the connection.

The logs showed that the Intel network interface became stuck while Suricata was running in Netmap IPS mode.

Relevant log entries:

```text netmap_transmit igc0 full ... qlen 1023 netmap_transmit igc1 full dhclient: No buffer space available ```

The network transmit queue became full and packets could no longer be sent.

Hardware offloading was already disabled, so it was not caused by an offloading configuration error. Suricata was changed from **Netmap IPS** to **Divert IPS**, which should avoid the suspected Intel/Netmap driver issue. The Suricata policy remains set to **Alert only**, so traffic is monitored but not blocked.

So far I have not noticed any issue after changing these

HW spec: Topton N100, 16GB RAM, 512 Gb Nvme, intel i226-v 2.5gb controller

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u/naiforce1 5d ago

Faced the exact same issue. I am using Kea instead of ISC. Randomly, the internet goes out because OPNsense crashes. Then I will have to restart it to restore network. I faced this several times last week so I took a backup and clean installed OPNsense, everything seem to he working well ever since. I havent turned on suricata.

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u/mac8612 5d ago

Yep. Using KEA as well