From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.5) Gecko/20011012 BuildID: Some IP names evaluate to multiple IP numbers. Sometimes one or more, but not all of the web (ftp, etc.) servers on one or more of these IP numbers are down, but not the others. Mozilla will (randomly?) choose to connect with one of the IP numbers. If this happens to be the down server, no connection will ever be made--it will time out. Reproducible: Sometimes Steps to Reproduce: 1. Create a web site with two (2) IP numbers 2. Run a web server on one, but not both 3. Attempt to view page from site, by name Actual Results: 50% of initial connections will be lost. (IP number from lookup seems to be kept until DNS timeout). Repeated attempts to reconnect to the site will all timeout (until you get another chance after DNS expiration). Expected Results: After short (5 seconds?) timeout, attempt to connect to another IP number for the site. Example: www.svt.se currently evaluates to three IP numbers, and it's A record has a 120-second expiration. If one of the three servers is down (which is common for the site), you have a 33 1/3% chance of failing to connect at all the first time you try to go to the site. If you hit ESC and attempt to try again, it will still fail, repeatedly until two minutes have passed, when you get to roll the dice again. If this were to occur on a site with a longer DNS expiration, you could get stuck on the bad IP number for however long...

->the dns cache

dupe of bug 86917 (socket transport should try all ip addresses returned by DNS service) *** This bug has been marked as a duplicate of 86917 ***