Nginx proxy pass - disable ipv6

Question

I have nginx conf as follows:

server {
listen       127.0.0.1:8080;
server_name  127.0.0.1;

client_max_body_size 20m;

include /etc/nginx/conf.d/services/*.conf;

# redirect server error pages to the static page /50x.html                                                                                                                                              
#                                                                                                                                                                                                       
error_page   500 /500.json;
error_page   501 /501.json;
error_page   502 /502.json;
error_page   503 /503.json;
error_page   504 /504.json;
error_page   404 /404.json;

location = /500.json {
    root   /opt/lj/nginx;
}
location = /501.json {
    root   /opt/lj/nginx;
}
location = /502.json {
    root   /opt/lj/nginx;
}
location = /503.json {
    root   /opt/lj/nginx;
}
location = /504.json {
    root   /opt/lj/nginx;
}
location = /404.json {
    root  /opt/lj/nginx;
}
}

In the conf.d/services directory, I have a file with:

location /api/auth {proxy_pass     http://127.0.0.1:8081;}

I have an upstream process listening on 8081 for requests. Almost accurately 2 our 3 times, the request gets redirected appropriately, but every third time, I get this error:

2014/10/09 03:03:52 [alert] 4572#0: *16 socket() failed (97: Address family not supported by protocol) while connecting to upstream, client: 127.0.0.1, server: 127.0.0.1, request: "GET /api/auth/1.0/companies/1/clients HTTP/1.1", upstream: "http://[::1]:8081/api/auth/1.0/companies/1/clients", host: "localhost:8080"

I don't know how to make nginx only forward to the IPv4 address which the upstream understands.

Access logs: (Please note 1 out of 3 attempts results in 500 while the rest pass)

127.0.0.1 - portalAdmin [09/Oct/2014:02:56:37 -0400] "GET /api/auth/1.0/companies/1/clients HTTP/1.1" 500 107 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2125.101 Safari/537.36" "98.207.234.244"
127.0.0.1 - portalAdmin [09/Oct/2014:02:57:38 -0400] "GET /api/auth/1.0/companies/1/clients HTTP/1.1" 200 2 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2125.101 Safari/537.36" "98.207.234.244"
127.0.0.1 - portalAdmin [09/Oct/2014:02:57:39 -0400] "GET /api/auth/1.0/companies/1/clients HTTP/1.1" 200 2 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2125.101 Safari/537.36" "98.207.234.244"
127.0.0.1 - portalAdmin [09/Oct/2014:02:57:41 -0400] "GET /api/auth/1.0/companies/1/clients HTTP/1.1" 500 107 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2125.101 Safari/537.36" "98.207.234.244"
127.0.0.1 - portalAdmin [09/Oct/2014:03:03:44 -0400] "GET /api/auth/1.0/companies/1/clients HTTP/1.1" 200 2 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2125.101 Safari/537.36" "98.207.234.244"
127.0.0.1 - portalAdmin [09/Oct/2014:03:03:45 -0400] "GET /api/auth/1.0/companies/1/clients HTTP/1.1" 200 2 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2125.101 Safari/537.36" "98.207.234.244"
127.0.0.1 - portalAdmin [09/Oct/2014:03:03:46 -0400] "GET /api/auth/1.0/companies/1/clients HTTP/1.1" 500 107 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2125.101 Safari/537.36" "98.207.234.244"
127.0.0.1 - portalAdmin [09/Oct/2014:03:03:50 -0400] "GET /api/auth/1.0/companies/1/clients HTTP/1.1" 200 2 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2125.101 Safari/537.36" "98.207.234.244"
127.0.0.1 - portalAdmin [09/Oct/2014:03:03:51 -0400] "GET /api/auth/1.0/companies/1/clients HTTP/1.1" 200 2 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2125.101 Safari/537.36" "98.207.234.244"
127.0.0.1 - portalAdmin [09/Oct/2014:03:03:52 -0400] "GET /api/auth/1.0/companies/1/clients HTTP/1.1" 500 107 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2125.101 Safari/537.36" "98.207.234.244"

Any help would be greatly appreciated! Thanks.

Answer 1

Maybe you have "localhost" instead of "127.0.0.1" somewhere in your config. You could specify a resolver and set ipv6 to off.

resolver 8.8.8.8 4.2.2.2 ipv6=off;

If your webservice on port 8081 is on nginx too, then enabling IPv6 for this could solve the problem.

server {
    listen 8081;
    listen [::]:8081;
    ....
}

Answer 2

I had the same issue. Changing the Ipv6only=on; ==> to ==> Ipv6only=off; didn't work for me. When I removed the "Ipv6only=off/on" completely - it started working like charm!

Try to remove to remove it completely and reloading nginx service.