Nginx forum returns 502 (2014-03-25T08:13Z)

Jim Ohlstein jim at
Wed Mar 26 13:23:34 UTC 2014


On 3/25/14, 6:50 PM, Jonathan Matthews wrote:
> On 25 March 2014 21:17, Jim Ohlstein <jim at> wrote:
>> [what does] that "T08:13Z" mean
> The Z suffix indicates UTC, as per section 2 of
> HTH,
> Jonathan

Thank you for educating me.

It's a busy server and I turn over logs frequently so unfortunately 
those requests are gone.

However, it seems that there are about half a dozen 502's this morning 
and I'm at a bit of a loss to explain them other than they all are 
coming from IPv6 addresses.

A little background perhaps, and maybe someone can offer assistance.

I've run a variety of PHP apps over the years. My preferences is to use 
FPM, but for some reason lately on this server, it has had several 
episodes where it just stops accepting new requests. It's running, it 
just doesn't seem to "see" the requests. I hadn't made any changes to 
the configuration, and use more or less the same configuration on a 
bunch of other machines with no issue. About three or four days ago I 
switched the forum to use an apache22 backend for PHP requests, with 
RPAF enabled while I looked into the FPM issue. Of course that has gone 
swimmingly, except that IPv6 requests seem to be generating 502's. 
Looking at the apache logs I don't even see the requests. Of course, FPM 
also hasn't experienced the same issue either in that time.

I believe it has something to do RPAF handles IPv6 addresses. For now I 
have put the forum back on a PHP-FPM backend while I try to sort this 
out. If I continue to have this problem I'll move the forum to another 
server if need be.

Jim Ohlstein

"Never argue with a fool, onlookers may not be able to tell the 
difference." - Mark Twain

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