In many cases it is noticed that long URLs are dropped by the PIX Firewall. This problem is especially noticed when integrated with the URL filter.
By default, if a URL exceeds the maximum permitted size, then it is dropped. In order to avoid this, enter this command to set the security appliance to truncate a long URL:
hostname(config)#filter url [longurl-truncate | longurl-deny | cgi-truncate]
The longurl-truncate option causes the security appliance to send only the hostname or IP address portion of the URL for evaluation to the filtering server when the URL is longer than the maximum length permitted. Use the longurl-deny option to deny outbound URL traffic if the URL is longer than the maximum permitted size.