Block AI Tools with Squid Proxy

# iptables rules to redirect HTTP/HTTPS traffic to Squid transparent proxy
# Run on the gateway/router where Squid is installed

# Redirect HTTP (port 80) to Squid on port 3129
iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 \
  -j REDIRECT --to-port 3129

# Redirect HTTPS (port 443) to Squid SSL bump on port 3130
iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 443 \
  -j REDIRECT --to-port 3130

# Exclude Squid's own traffic from redirection (prevent loops)
iptables -t nat -A OUTPUT -m owner --uid-owner proxy -j ACCEPT

# squid.conf — Transparent proxy ports
http_port 3129 intercept
https_port 3130 intercept ssl-bump \
  cert=/etc/squid/ssl/squid-ca-cert.pem \
  key=/etc/squid/ssl/squid-ca-key.pem \
  generate-host-certificates=on dynamic_cert_mem_cache_size=4MB

# AI blocklist ACL works the same in transparent mode
acl ai_tools_blocked dstdomain "/etc/squid/blocklists/ai-tools-domains.txt"
http_access deny ai_tools_blocked

#!/bin/bash
# /usr/local/bin/update-ai-blocklist.sh
# Downloads the latest AI tool domain list and reloads Squid

FEED_URL="https://feeds.aitoolsblocklist.com/v1/domains?format=squid&key=YOUR_API_KEY"
BLOCKLIST="/etc/squid/blocklists/ai-tools-domains.txt"
TMPFILE="/tmp/ai-tools-domains-new.txt"
MIN_LINES=30000

# Download the latest list
curl -s -f -o "$TMPFILE" "$FEED_URL"
if [ $? -ne 0 ]; then
    echo "[$(date)] ERROR: Failed to download AI blocklist" >> /var/log/squid/blocklist-update.log
    exit 1
fi

# Validate minimum domain count
LINES=$(wc -l < "$TMPFILE")
if [ "$LINES" -lt "$MIN_LINES" ]; then
    echo "[$(date)] ERROR: Downloaded list has only $LINES lines (expected $MIN_LINES+)" >> /var/log/squid/blocklist-update.log
    rm -f "$TMPFILE"
    exit 1
fi

# Backup current list and deploy new one
cp "$BLOCKLIST" "${BLOCKLIST}.bak"
mv "$TMPFILE" "$BLOCKLIST"
chown proxy:proxy "$BLOCKLIST"

# Reload Squid configuration
squid -k reconfigure
echo "[$(date)] SUCCESS: Updated AI blocklist ($LINES domains), Squid reloaded" >> /var/log/squid/blocklist-update.log

# Cron entry — run the update script daily at 3:00 AM
0 3 * * * /usr/local/bin/update-ai-blocklist.sh

# squid.conf — LDAP authentication with per-group AI blocking

# LDAP authentication helper
auth_param basic program /usr/lib/squid/basic_ldap_auth \
  -b "dc=corp,dc=example,dc=com" \
  -f "(&(objectClass=user)(sAMAccountName=%s))" \
  -h ldap.corp.example.com -D "CN=squid-svc,OU=Service,DC=corp,DC=example,DC=com" -W /etc/squid/ldap-pass
auth_param basic children 20
auth_param basic realm "Corporate Proxy"

# LDAP group membership helper
external_acl_type ldap_group %LOGIN /usr/lib/squid/ext_ldap_group_acl \
  -b "dc=corp,dc=example,dc=com" \
  -f "(&(objectClass=group)(cn=%g)(member=%u))" \
  -h ldap.corp.example.com -D "CN=squid-svc,OU=Service,DC=corp,DC=example,DC=com" -W /etc/squid/ldap-pass

# Define user group ACLs
acl authenticated proxy_auth REQUIRED
acl engineering_group external ldap_group Engineering
acl finance_group external ldap_group Finance
acl all_staff external ldap_group AllStaff

# AI domain blocklists — full and category-specific
acl ai_all dstdomain "/etc/squid/blocklists/ai-tools-all.txt"
acl ai_code dstdomain "/etc/squid/blocklists/ai-tools-code.txt"
acl ai_text dstdomain "/etc/squid/blocklists/ai-tools-text.txt"

# Policy: Engineering can access code AI, blocked from text AI
http_access allow engineering_group ai_code
http_access deny engineering_group ai_text

# Policy: Finance blocked from all AI tools
http_access deny finance_group ai_all

# Policy: All other staff — block all AI tools
http_access deny all_staff ai_all