[SOLVED] Proxy problems?

[pvdleek]

I have a few visitors of my website that are complaining that they get an instant white page instead of my website. The similarity between those visitors seems to be that they are behind a proxy.
My website is behind an XR load balancer (made redundant with heartbeat) that balances over 6 webservers.

-bash-3.2# xr -V
XR version : 2.54
Written by : Karel Kubat <karel@kubat.nl>
Maintained by : Karel Kubat <karel@kubat.nl>
Primary site : http://crossroads.e-tunity.com
Compiled with : /usr/bin/g++
Optimization : -O3
System : Linux
Libraries : -L/usr/lib -lnsl -lpthread -lm
Type sizes : ssize_t=4, int=4, long=4, double=8, ptr=4
getopt.h : present
INADDR_NONE : present
getopt_long() : present
inet_aton() : present
strnstr() : absent

-bash-3.2# ps ax | grep xr
6752 ? Sl 0:06 xr -x -C -c 60 -t 30 -d S:600 --server http:0:80 --backend *.*.*.*:80 --backend *.*.*.*:80 --backend *.*.*.*:80 --backend *.*.*.*:80 --backend *.*.*.*:80 --backend *.*.*.*:80
6753 ? S 0:00 logger -t xr-web
(I masked the IP's)

In my website I have seen that some of these users have multiple IP addresses, they come comma seperated in the headers, for example 1.2.3.4,5.6.7.8,9.10.11.12

I've searched the forum but found no meaningful messages on proxy behaviour, so I'm wondering if it's even something in XR or maybe in my website...

[pvdleek]

Ouch, stupid me. I found a huge bug in my website. It's working again now.

Can an admin please move this discussion to "Crossroads Help" because I would still like an answer to my question about the multiple IP's. Why do some users have multiple IP's seperated by a comma?

[Karel]

Why do some users have multiple IP's seperated by a comma?

That would be a side effect of the proxy. The downstream HTTP server will typically only see the IP of its direct client (the proxy), so the proxy adds the IP of its own client to the list, in order to enable the downstream server to see it. Most typically this is e.g. (without XR in between):

Browser, e.g. at 1.2.3.4 --> proxy, e.g. at 192.168.1.1 --> Apache, e.g. at 192.168.1.100

The client IP list at the Apache server would then typically state both 1.2.3.4 and 192.168.1.1.

Hope this helps, Karel

[pvdleek]

This certainly helps, thanks.
In your example the browser IP is the first in the list. Is that always the case or do proxies behave differently?

[Karel]

In your example the browser IP is the first in the list. Is that always the case or do proxies behave differently?

TBH, I don't know offhand, you would need to check it... I think that the Apache proxy module handles it the way I described, but I'm not even sure there

[pvdleek]

Ok, thanks for your replies.