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Tools: Reducing Office Bandwidth With Squid Caching, HTB QoS, and Category Filtering: A Technical Walkthrough (2026)

2026-05-19 0 views admin
Tools: Reducing Office Bandwidth With Squid Caching, HTB QoS, and Category Filtering: A Technical Walkthrough (2026)

Web caching: Squid configuration and cache hit mechanics

What drives cache hit rate

HTTPS and the SSL inspection requirement

QoS: HTB + SFQ with tc

Content filtering: eliminate non-work bandwidth entirely

Combined effect Three techniques reduce office internet bandwidth consumption: web caching (reduce traffic volume), QoS (prioritize what reaches the connection), and content filtering (eliminate unnecessary traffic). Here is the technical implementation of each. Squid is the standard open-source proxy cache. Cache hit rate — the proportion of requests served from cache — determines actual bandwidth savings. The Cache-Control response header determines cacheability: In practice, most SaaS application responses are Cache-Control: no-store or private. Static assets (CSS, JS, images, fonts, software packages) are typically cacheable. Realistic cache hit rates in an office environment: 15-40% of requests by count, but static assets are small — actual bandwidth savings may be 10-25% of bytes transferred. HTTPS traffic is not cacheable without SSL inspection. The proxy cannot read Cache-Control headers in an encrypted response. Enabling ssl-bump (TLS MITM) makes HTTPS content cacheable and dramatically increases hit rates: HTB (Hierarchical Token Bucket) guarantees bandwidth minimums and allows borrowing from idle classes. SFQ (Stochastic Fairness Queuing) provides per-flow fairness within each class. Category-based URL filtering removes streaming, file-sharing, and social media traffic during business hours — not throttled, eliminated: Time-based rules restrict blocking to business hours; outside those hours all traffic is permitted. On a typical 30-person office network: The sequence matters: cache first (reduce volume), shape second (manage what remains), filter third (eliminate unnecessary load). CacheGuard ships Squid, HTB+SFQ QoS, and URL filtering pre-integrated in a single appliance OS, configured through a browser-based interface. → https://www.cacheguard.com/reduce-internet-bandwidth-usage-office/ Templates let you quickly answer FAQs or store snippets for re-use. Are you sure you want to ? It will become hidden in your post, but will still be visible via the comment's permalink. Hide child comments as well For further actions, you may consider blocking this person and/or reporting abuse

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# /etc/squid/squid.conf — basic caching configuration cache_mem 512 MB maximum_object_size_in_memory 1 MB cache_dir ufs /var/spool/squid 20000 16 256 maximum_object_size 200 MB minimum_object_size 0 KB # Cache freshness refresh_pattern ^ftp: 1440 20% 10080 refresh_pattern ^gopher: 1440 0% 1440 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0 refresh_pattern . 0 20% 4320 # /etc/squid/squid.conf — basic caching configuration cache_mem 512 MB maximum_object_size_in_memory 1 MB cache_dir ufs /var/spool/squid 20000 16 256 maximum_object_size 200 MB minimum_object_size 0 KB # Cache freshness refresh_pattern ^ftp: 1440 20% 10080 refresh_pattern ^gopher: 1440 0% 1440 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0 refresh_pattern . 0 20% 4320 # /etc/squid/squid.conf — basic caching configuration cache_mem 512 MB maximum_object_size_in_memory 1 MB cache_dir ufs /var/spool/squid 20000 16 256 maximum_object_size 200 MB minimum_object_size 0 KB # Cache freshness refresh_pattern ^ftp: 1440 20% 10080 refresh_pattern ^gopher: 1440 0% 1440 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0 refresh_pattern . 0 20% 4320 Cache-Control Cache-Control: max-age=86400 # Cacheable for 24 hours → cache hit on repeat request Cache-Control: no-store # Never cached → always fetches from origin Cache-Control: private # Browser cache only, not proxy → always fetches Cache-Control: max-age=86400 # Cacheable for 24 hours → cache hit on repeat request Cache-Control: no-store # Never cached → always fetches from origin Cache-Control: private # Browser cache only, not proxy → always fetches Cache-Control: max-age=86400 # Cacheable for 24 hours → cache hit on repeat request Cache-Control: no-store # Never cached → always fetches from origin Cache-Control: private # Browser cache only, not proxy → always fetches Cache-Control: no-store Cache-Control # ssl-bump for HTTPS caching http_port 3128 ssl-bump cert=/etc/squid/ca.pem key=/etc/squid/ca.key ssl_bump stare all ssl_bump bump all # Exempt domains that use certificate pinning acl no_ssl_bump ssl::server_name_regex -i apple.com google--weight: 500;">update.com ssl_bump splice no_ssl_bump # ssl-bump for HTTPS caching http_port 3128 ssl-bump cert=/etc/squid/ca.pem key=/etc/squid/ca.key ssl_bump stare all ssl_bump bump all # Exempt domains that use certificate pinning acl no_ssl_bump ssl::server_name_regex -i apple.com google--weight: 500;">update.com ssl_bump splice no_ssl_bump # ssl-bump for HTTPS caching http_port 3128 ssl-bump cert=/etc/squid/ca.pem key=/etc/squid/ca.key ssl_bump stare all ssl_bump bump all # Exempt domains that use certificate pinning acl no_ssl_bump ssl::server_name_regex -i apple.com google--weight: 500;">update.com ssl_bump splice no_ssl_bump # Attach HTB root qdisc to WAN interface tc qdisc add dev eth0 root handle 1: htb default 30 # Total bandwidth: 100Mbit tc class add dev eth0 parent 1: classid 1:1 htb rate 100mbit # Class 1:10 — Real-time (VoIP, video calls): 20Mbit guaranteed, burst to 100Mbit tc class add dev eth0 parent 1:1 classid 1:10 htb rate 20mbit ceil 100mbit prio 1 # Class 1:20 — Business traffic: 70Mbit guaranteed tc class add dev eth0 parent 1:1 classid 1:20 htb rate 70mbit ceil 100mbit prio 2 # Class 1:30 — Bulk/background: 10Mbit guaranteed, capped at 30Mbit tc class add dev eth0 parent 1:1 classid 1:30 htb rate 10mbit ceil 30mbit prio 3 # Add SFQ to each leaf class for per-flow fairness tc qdisc add dev eth0 parent 1:10 handle 10: sfq perturb 10 tc qdisc add dev eth0 parent 1:20 handle 20: sfq perturb 10 tc qdisc add dev eth0 parent 1:30 handle 30: sfq perturb 10 # Classify traffic: DSCP EF (VoIP/video) → high priority class tc filter add dev eth0 parent 1:0 protocol ip prio 1 u32 \ match ip tos 0xb8 0xfc flowid 1:10 # Classify HTTP/HTTPS to business class tc filter add dev eth0 parent 1:0 protocol ip prio 2 u32 \ match ip dport 443 0xffff flowid 1:20 # Everything else → bulk class (default 30) # Attach HTB root qdisc to WAN interface tc qdisc add dev eth0 root handle 1: htb default 30 # Total bandwidth: 100Mbit tc class add dev eth0 parent 1: classid 1:1 htb rate 100mbit # Class 1:10 — Real-time (VoIP, video calls): 20Mbit guaranteed, burst to 100Mbit tc class add dev eth0 parent 1:1 classid 1:10 htb rate 20mbit ceil 100mbit prio 1 # Class 1:20 — Business traffic: 70Mbit guaranteed tc class add dev eth0 parent 1:1 classid 1:20 htb rate 70mbit ceil 100mbit prio 2 # Class 1:30 — Bulk/background: 10Mbit guaranteed, capped at 30Mbit tc class add dev eth0 parent 1:1 classid 1:30 htb rate 10mbit ceil 30mbit prio 3 # Add SFQ to each leaf class for per-flow fairness tc qdisc add dev eth0 parent 1:10 handle 10: sfq perturb 10 tc qdisc add dev eth0 parent 1:20 handle 20: sfq perturb 10 tc qdisc add dev eth0 parent 1:30 handle 30: sfq perturb 10 # Classify traffic: DSCP EF (VoIP/video) → high priority class tc filter add dev eth0 parent 1:0 protocol ip prio 1 u32 \ match ip tos 0xb8 0xfc flowid 1:10 # Classify HTTP/HTTPS to business class tc filter add dev eth0 parent 1:0 protocol ip prio 2 u32 \ match ip dport 443 0xffff flowid 1:20 # Everything else → bulk class (default 30) # Attach HTB root qdisc to WAN interface tc qdisc add dev eth0 root handle 1: htb default 30 # Total bandwidth: 100Mbit tc class add dev eth0 parent 1: classid 1:1 htb rate 100mbit # Class 1:10 — Real-time (VoIP, video calls): 20Mbit guaranteed, burst to 100Mbit tc class add dev eth0 parent 1:1 classid 1:10 htb rate 20mbit ceil 100mbit prio 1 # Class 1:20 — Business traffic: 70Mbit guaranteed tc class add dev eth0 parent 1:1 classid 1:20 htb rate 70mbit ceil 100mbit prio 2 # Class 1:30 — Bulk/background: 10Mbit guaranteed, capped at 30Mbit tc class add dev eth0 parent 1:1 classid 1:30 htb rate 10mbit ceil 30mbit prio 3 # Add SFQ to each leaf class for per-flow fairness tc qdisc add dev eth0 parent 1:10 handle 10: sfq perturb 10 tc qdisc add dev eth0 parent 1:20 handle 20: sfq perturb 10 tc qdisc add dev eth0 parent 1:30 handle 30: sfq perturb 10 # Classify traffic: DSCP EF (VoIP/video) → high priority class tc filter add dev eth0 parent 1:0 protocol ip prio 1 u32 \ match ip tos 0xb8 0xfc flowid 1:10 # Classify HTTP/HTTPS to business class tc filter add dev eth0 parent 1:0 protocol ip prio 2 u32 \ match ip dport 443 0xffff flowid 1:20 # Everything else → bulk class (default 30) # SquidGuard integration for category-based filtering url_rewrite_program /usr/bin/squidGuard -c /etc/squidguard/squidGuard.conf # SquidGuard integration for category-based filtering url_rewrite_program /usr/bin/squidGuard -c /etc/squidguard/squidGuard.conf # SquidGuard integration for category-based filtering url_rewrite_program /usr/bin/squidGuard -c /etc/squidguard/squidGuard.conf # /etc/squidguard/squidGuard.conf dbhome /var/lib/squidguard/db logdir /var/log/squidguard dest streaming { domainlist streaming/domains urllist streaming/urls } dest social { domainlist social/domains } acl { # Apply during business hours default { pass !streaming !social all redirect http://gateway/blocked.html } } # /etc/squidguard/squidGuard.conf dbhome /var/lib/squidguard/db logdir /var/log/squidguard dest streaming { domainlist streaming/domains urllist streaming/urls } dest social { domainlist social/domains } acl { # Apply during business hours default { pass !streaming !social all redirect http://gateway/blocked.html } } # /etc/squidguard/squidGuard.conf dbhome /var/lib/squidguard/db logdir /var/log/squidguard dest streaming { domainlist streaming/domains urllist streaming/urls } dest social { domainlist social/domains } acl { # Apply during business hours default { pass !streaming !social all redirect http://gateway/blocked.html } } - Web caching (with SSL inspection): 15-30% of bytes served locally - QoS: no bandwidth saved, but VoIP/video call quality maintained under load - Content filtering (streaming blocked 9-18h): 20-40% reduction in peak-hour bytes

🏷️ Tags

toolsutilitiessecurity toolsreducingofficebandwidthsquidcachingcategoryfiltering

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