diff --git a/Dockerfile b/Dockerfile
index 975bc7d..58bec12 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,10 +2,28 @@ FROM python:2.7-slim
 
 WORKDIR /app
 
+# fix EOL debian buster repos and install build dependencies for pyasn
+RUN sed -i 's/deb.debian.org/archive.debian.org/g' /etc/apt/sources.list && \
+    sed -i 's/security.debian.org/archive.debian.org/g' /etc/apt/sources.list && \
+    sed -i '/buster-updates/d' /etc/apt/sources.list && \
+    apt-get update && apt-get install -y --no-install-recommends gcc libc-dev && \
+    rm -rf /var/lib/apt/lists/*
+
 # install dependencies (optional - bs4 can be skipped with --nobs)
 COPY requirements.txt .
 RUN pip install -r requirements.txt || true
 
+# download ASN database for pyasn (if pyasn installed successfully)
+RUN mkdir -p /app/data && \
+    python -c "import pyasn" 2>/dev/null && \
+    pyasn_util_download.py --latest && \
+    pyasn_util_convert.py --single rib.*.bz2 /app/data/ipasn.dat && \
+    rm -f rib.*.bz2 || \
+    echo "pyasn database setup skipped"
+
+# remove build dependencies to keep image small
+RUN apt-get purge -y gcc libc-dev && apt-get autoremove -y || true
+
 COPY . .
 
 # default: run syntax check
diff --git a/README.md b/README.md
index e7d856b..1c77281 100644
--- a/README.md
+++ b/README.md
@@ -142,6 +142,7 @@ Query parameters:
 - `limit` - Max results (default: 100)
 - `proto` - Filter by protocol (socks4/socks5/http)
 - `country` - Filter by country code
+- `asn` - Filter by ASN number
 - `format` - Output format (json/plain)
 
 ## Architecture
@@ -175,6 +176,7 @@ Each proxy is tested against 3 random targets:
 proxy TEXT UNIQUE      -- ip:port
 proto TEXT             -- socks4/socks5/http
 country TEXT           -- 2-letter code
+asn INT                -- autonomous system number
 failed INT             -- consecutive failures
 success_count INT      -- total successes
 avg_latency REAL       -- rolling average (ms)