Opened 4 years ago

Closed 4 years ago

#889 closed defect (invalid)

proxy_set_header: $remote_addr value seems inconsistent

Reported by: Mathieu MD Owned by:
Priority: minor Milestone:
Component: nginx-core Version: 1.6.x
Keywords: Cc:
uname -a: Linux nginx01 2.6.32-40-pve #1 SMP Fri Jul 24 11:16:05 CEST 2015 i686 GNU/Linux
nginx -V: TLS SNI support enabled
configure arguments: --with-cc-opt='-g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2' --with-ld-opt=-Wl,-z,relro --prefix=/usr/share/nginx --conf-path=/etc/nginx/nginx.conf --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --lock-path=/var/lock/nginx.lock --pid-path=/run/nginx.pid --http-client-body-temp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-proxy-temp-path=/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-debug --with-pcre-jit --with-ipv6 --with-http_ssl_module --with-http_stub_status_module --with-http_realip_module --with-http_auth_request_module --with-http_addition_module --with-http_dav_module --with-http_geoip_module --with-http_gzip_static_module --with-http_image_filter_module --with-http_spdy_module --with-http_sub_module --with-http_xslt_module --with-mail --with-mail_ssl_module --add-module=/build/nginx-JCwXQ6/nginx-1.6.2/debian/modules/nginx-auth-pam --add-module=/build/nginx-JCwXQ6/nginx-1.6.2/debian/modules/nginx-dav-ext-module --add-module=/build/nginx-JCwXQ6/nginx-1.6.2/debian/modules/nginx-echo --add-module=/build/nginx-JCwXQ6/nginx-1.6.2/debian/modules/nginx-upstream-fair --add-module=/build/nginx-JCwXQ6/nginx-1.6.2/debian/modules/ngx_http_substitutions_filter_module

Description

Hello,

In a proxy_pass setting, the proxy_set_header set the X-Real-IP header value to $remote_addr only when a string is appended to it.

With this configuration, the X-Real-IP header is not set on the backend server:

location / {
  proxy_pass http://10.1.2.3/;
  proxy_redirect off;
  proxy_buffering off;
  proxy_set_header X-Real-IP $remote_addr;
}

However, just appending anything (here a "test" string) to the $remote_addr variable would make it work (here, X-Real-IP is set to 192.168.1.1\"test\" on the backend server)

location / {
  proxy_pass http://10.1.2.3/;
  proxy_redirect off;
  proxy_buffering off;
  proxy_set_header X-Real-IP $remote_addr"test";
}

Am I missing something?

Change History (3)

comment:1 by Maxim Dounin, 4 years ago

Works fine here, even with 1.6.2 (which is legacy and not supported anymore). I would recommend to try the following:

  • Check if the header is actually absent in requests sent by nginx, either using tcpdump or debug log.
  • Check if you are able to reproduce the problem with recent nginx versions (1.9.10 is a good choice) and without 3rd party modules.

comment:2 by Mathieu MD, 4 years ago

I am sorry, it was a PEBKAC mistake!
For the record, I was expecting the backend (Apache) logs to contains the X-Real-IP, but was still using %h instead of %a in LogFormat. Cf. this Apache mod_remoteip and access logs at Serverfault.
Sorry for the noise. And thank you very much for your useful answer.

comment:3 by Maxim Dounin, 4 years ago

Resolution: invalid
Status: newclosed

Ok, closing this.

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