Frontend cookie not being set until first login attempt

Question

I'm currently migrating a site from Magento 1.7.0.2 to 1.8.1. I'm following the instructions outlined on the Magento site, so I've created a development account and ported over my theme, extensions and a copy of the database.

I'm facing a strange problem in that the frontend cookie is not being generated until a user tries to login - so on first login attempt (successful or otherwise), Magento redirects to the login page. After the first attempt, login and other site functionality behave as expected.

I have been through my theme and ensured any forms I have feature the form key introduced in 1.8 - but my login template uses the the base default Magento 1.8 anyhow. I've also tried switching to the default theme, with same behaviour.

There are no core overrides in the install, and I've tried disabling all extensions. Same result.

I've tried playing with the cookie domain value in the admin area - leaving it blank, specifically the sub-domain or for the whole domain. Behaviour is the same.

If I visit the current 1.7.0.2 site I get frontend cookie set on first page load, as expected.

Any ideas what's happening or what I can do to fix it?

Answer 1

In the end I found this issue related to server configuration. The staging site was on a server with Varnish installed.

Varnish was set to ignore the staging site url in the configuration, but it was still interfering with the cookie creation somehow - despite not otherwise caching the site in any way.

Using a non-standard port, to bypass Varnish completely, immediately resolved the issue.

I'm still investigating why Varnish caused this issue - if and when I have more information I will update this answer.