Enable server support for ipv6 causes ipv4 to break.

My plex recently stopped responding web requests. It took me a long time, but I finally figured it out. It was hard to diagnose, since the plex server process was running, but the web server wasn’t responding. When I did telnet localhost 32400 it worked, which was puzzling.

Anyways, I finally realized that I had recently enabled (and forgot that I did) the IPV6 support. I recently got native ipv6 support from my ISP and wanted to try it out. It looks like when you enable IPV6 you also DISABLE ipv4. This was causing all sorts of trouble for me.

root@plexmediaserver_1:/var/db/plexdata/Plex Media Server/Logs # sockstat -l | grep 32400
plex     Plex Media 80560 55 tcp6   *:32400    

My freenas jail isn’t actually configured for IPV6, so this is where problems started.

I think you need to always allow IPV4, and make this IPV6 an additional port that is being listened on. OR, you should have 2 checkboxes, one for each network.

Anyways, I finally figure it out, and I’m good now. Just posting here to express a configuration problem that was tough to diagnose in the hopes that it may help someone else, or maybe the plex devs can make it easier to avoid this problem with server setup improvements.

Thanks!!!

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How were you able to recover? I am having the exact same issue.

the problem is ipv6 sockets can only talk speak ipv6 and not v4mapped
sysctl net.inet6.ip6.v6only=0

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I enabled ipv6 and can’t access my server now too (also in a freenas jail), how can I revert this / what config file can I manually edit to turn ipv6 off?

EnableIPv6 in the Preferences file: https://support.plex.tv/hc/en-us/articles/201105343-Advanced-Server-Settings

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Just wanted to bump this, thanks for the solution. This is a stupid option to have hanging out in settings without any warning about it breaking all ipv4 functionality. Just spent the past 45 minutes furiously googling
after accidentally rendering my server useless only to eventually find this and solve the issue. Good lord…

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Just a small warning to folks that enabling IPv6 support on the Windows 10 client will disable direct connections from Xbox One S and PS4 Pro.