Smoothwall Express (Ver. 2 & 3) support squids download throttling AKA delay_pools.
This feature allows you to cap download speeds based upon different criteria, for example on URL or Mime Type.
To utilize this feature you must edit the file /var/smoothwall/proxy/acl
(Do not edit squid.conf directly because Smoothwall rebuilds it everytime squid is restarted!)
The Advanced Proxy mod for Smoothwall has a primitive WebUI for employing delay pools.
ACLs
ACLs or Access Control Lists can be thought of categories or groups. These groups are then used to match against access rules.
Group A = Access
Group B = Deny
You can also invert the groups with a "!"
Group !A = Deny (Groups other than A Deny)
There are many types of ACLs such as Source IP, Destination IP, Port, Protocol, Time, and URL just to name a few.
NOTE: ACLs have many options and many uses which are far beyond the scope of this article. For more info on ACLs see the ACL link in the References section.
ACL Example
# LunchTime ACL acl lunchtime time 11:30-1:30 # Video Files ACL acl video req_mime_type -i .avi .mpeg .mpe .mpg .qt .ram .rm .mov .fla .swf # Audio Files ACL acl audio req_mime_type -i .mp3 .wav .ogg .wma # Youtube ACL acl youtube url_regex -i www.youtube.com
Delay Pools
Delay Pools create buckets much like a HTB Quality of Service. This bucket is filled and then refilled at a given interval.
Think of it as a glass of beer and when ever the glass is half empty a bartender tops it off, but he pours slowly.
Initially the beer is filled up quickly, but after the beer is half gone the flow of beer is controlled.
Example Delay Pool
# Number of Delay Pools delay_pools 1 #First delay class (1) of second type (3). delay_class 1 3 # Speed Control (Pool#,Network,Individual) Rate/Bucket Size # 384Kbit or 48KByte / 768Kbit or 96KByte delay_parameters 1 -1/-1 48000/96000 # Apply throttling delay_access 1 lunchtime deny # Deny Throttling at lunch time delay_access 1 !lunchtime allow # Allow Throttling any time other than lunch time delay_access 1 allow youtube # Allow Throttling to www.youtube.com delay_access 1 allow video # Allow Throttling of video files delay_access 1 allow audio # Allow Throttling of audio files