[GH-ISSUE #327] Network namespace slows Firefox to a crawl #230

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opened 2026-05-05 05:21:59 -06:00 by gitea-mirror · 2 comments

gitea-mirror commented

2026-05-05 05:21:59 -06:00

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Originally created by @chiraag-nataraj on GitHub (Feb 27, 2016).
Original GitHub issue: https://github.com/netblue30/firejail/issues/327

I'm not entirely sure what's going on - maybe I just don't understand the way network namespaces work. When I try to run Firefox with the --net=wlan0 option, it slows to a crawl. Thinking that it might be the netfilter in the default profile, I added --ignore=netfilter, but Firefox was still just as slow. I then used --join-network=<pidof iceweasel> and attempted to ping google.com, which failed. Frustrated, I did a simple firejail --net=wlan0 --noprofile bash and again tried ping4 google.com which again didn't work. I thought --net=wlan0 (or an equivalent command) was not supposed to deny internet access? What's going on? I tested ping4 google.com on the regular system and it works fine.

[Note]: I'm using firejail 0.9.38.

Originally created by @chiraag-nataraj on GitHub (Feb 27, 2016). Original GitHub issue: https://github.com/netblue30/firejail/issues/327 I'm not entirely sure what's going on - maybe I just don't understand the way network namespaces work. When I try to run Firefox with the `--net=wlan0` option, it slows to a crawl. Thinking that it might be the `netfilter` in the default profile, I added `--ignore=netfilter`, but Firefox was still just as slow. I then used `--join-network=<pidof iceweasel>` and attempted to ping google.com, which failed. Frustrated, I did a simple `firejail --net=wlan0 --noprofile bash` and again tried `ping4 google.com` which again didn't work. I thought `--net=wlan0` (or an equivalent command) was not supposed to deny internet access? What's going on? I tested `ping4 google.com` on the regular system and it works fine. [Note]: I'm using firejail 0.9.38.

gitea-mirror

2026-05-05 05:21:59 -06:00

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gitea-mirror commented

2026-05-05 05:22:05 -06:00

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@netblue30 commented on GitHub (Feb 27, 2016):

--net and --interface are not supported on wlan interfaces. The kernel cannot attach a macvlan driver to them, I'll have to add a note in the man page, thanks for pointing it out.

@netblue30 commented on GitHub (Feb 27, 2016): --net and --interface are not supported on wlan interfaces. The kernel cannot attach a macvlan driver to them, I'll have to add a note in the man page, thanks for pointing it out.

gitea-mirror commented

2026-05-05 05:22:08 -06:00

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@chiraag-nataraj commented on GitHub (Feb 27, 2016):

Ah okay thanks!

@chiraag-nataraj commented on GitHub (Feb 27, 2016): Ah okay thanks!

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Reference: github-starred/firejail#230

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