Can't login with varnish enabled I can't login from the front-end with varnish installed.
Here's what I think it is issue

sub vcl_recv {

 # Do not cache these paths.
 if (req.url ~ "^/status\.php$" ||
  req.url ~ "^/admin$" ||
  req.url ~ "^/admin/.*$" ||
  req.url ~ "^/admin/?" ||
  req.url ~ "^/user" ||
  req.url ~ "^/user/.*$" ||
  req.url ~ "^/users/.*$") {
  return (pass);
 }


and the session cookies

if (req.http.Cookie) {
    set req.http.Cookie = ";" + req.http.Cookie;
    set req.http.Cookie = regsuball(req.http.Cookie, "; +", ";");
    set req.http.Cookie = regsuball(req.http.Cookie, ";(SESS[a-z0-9]+|NO_CACHE)=", "; \1=");
    set req.http.Cookie = regsuball(req.http.Cookie, ";(SESS[a-z0-9]+|SSESS[a-z0-9]+|NO_CACHE)=", "; \1=");


If I try to login directly from apache port:8000 it works as expected.
Here's the whole default.vcl file: http://pastebin.com/qPRyFEjP

I don't get why it's not piping to the authenticated users. Why wouldn't it login in?
Thanks.
The offending parts in your VCL are (line 53):

# Drop any cookies sent to Drupal.

 if (!(req.url ~ "install\.php|update\.php|cron\.php|admin\.php")) {
 unset req.http.cookie;
 }


and (line 81):

# Drop any cookies Drupal tries to send back to the client. This will make it unpossible to login, unless you filter it a bit better that it is made below
sub vcl_fetch {
 if (!(req.url ~ "install\.php|update\.php|cron\.php|admin\.php")) {
  unset beresp.http.set-cookie;
 }
}


Remove both of them.