Dear i have tested the squid 3.4 ( 3.4.0.1-20130909-r12987 )
There is some issue in regex_pattern (but i see that it will be fixed it in squid 3.4.0.2)
I'm using %>eui in access.log in order to track MAC address.It seems that this version is not able to detect MAC and write 00:00:00:00:00:00 instead real MAC address.
In 3.3.8 it is working as expected. Best regards
