User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.3) Gecko/20030312 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.3) Gecko/20030312 It is a known problem that multiple return values from a proxy auto-config (PAC) scripts are ignored and only the first one is used. This is very inconvenient if one wants to provide proxy fail-over solution. For example, Internet Explorer and Opera does not have this problem. Reproducible: Always Steps to Reproduce: 1. Create proxy-auto config file that return multiple values, for example: function FindProxyForURL(url, host) { return "PROXY 192.168.0.1:8080; 192.168.0.2:8080; DIRECT"; } 2. Make the proxy at 192.168.0.1 unavailable. 3. Try to open some page Actual Results: Mozilla fails with error message that the proxy server cannot be contacted. Expected Results: Mozilla should try the next entry in the returned chains of servers and not fail on the first one.

This is fixed in Mozilla 1.4b *** This bug has been marked as a duplicate of 84798 ***

Can you tell me what you searched for? The name of the bug probably should have been improved, because we get a ton of dupes.

Sorry about this! I searched for "FindProxyForURL" and "proxy auto-config". Didn't tried "failover" as PAC files are not only for failover but also for load balancing support or general proxy configuration.