# Ignoring Domains
There are two main reasons why you may want to exempt some traffic from mitmproxy’s interception mechanism:
- Certificate pinning: Some traffic is is protected using Certificate Pinning and mitmproxy’s interception leads to errors. For example, the Twitter app, Windows Update or the Apple App Store fail to work if mitmproxy is active.
- Convenience: You really don’t care about some parts of the traffic and just want them to go away. Note that mitmproxy’s “Limit” option is often the better alternative here, as it is not affected by the limitations listed below.
If you want to peek into (SSL-protected) non-HTTP connections, check out the tcp_proxy feature. If you want to ignore traffic from mitmproxy’s processing because of large response bodies, take a look at the streaming feature.
ignore_hosts option allows you to specify a regex which is matched against
host:port string (e.g. “example.com:443”) of a connection. Matching hosts
are excluded from interception, and passed on unmodified.
There are two important quirks to consider:
- In transparent mode, the ignore pattern is matched against the IP and
ClientHello SNI host. While we usually infer the hostname from the Host
header if the
ignore_hostsoption is set, we do not have access to this information before the SSL handshake. If the client uses SNI however, then we treat the SNI host as an ignore target.
- In regular and upstream proxy mode, explicit HTTP requests are never ignored. The ignore pattern is applied on CONNECT requests, which initiate HTTPS or clear-text WebSocket connections.
If you just want to ignore one specific domain, there’s usually a bulletproof method to do so:
- Run mitmproxy or mitmdump in verbose mode (
-v) and observe the
host:portinformation in the serverconnect messages. mitmproxy will filter on these.
- Take the
host:portstring, surround it with ^ and $, escape all dots (. becomes \.) and use this as your ignore pattern:
>>> mitmdump -v 127.0.0.1:50588: clientconnect 127.0.0.1:50588: request -> CONNECT example.com:443 HTTP/1.1 127.0.0.1:50588: Set new server address: example.com:443 127.0.0.1:50588: serverconnect -> example.com:443 ^C >>> mitmproxy --ignore-hosts ^example\.com:443$
Here are some other examples for ignore patterns:
# Exempt traffic from the iOS App Store (the regex is lax, but usually just works): --ignore-hosts apple.com:443 # "Correct" version without false-positives: --ignore-hosts '^(.+\.)?apple\.com:443$' # Ignore example.com, but not its subdomains: --ignore-hosts '^example.com:' # Ignore everything but example.com and mitmproxy.org: --ignore-hosts '^(?!example\.com)(?!mitmproxy\.org)' # Transparent mode: --ignore-hosts 17\.178\.96\.59:443 # IP address range: --ignore-hosts 17\.178\.\d+\.\d+:443
- This stems from an limitation of explicit HTTP proxying: A single connection
can be re-used for multiple target domains - a
GET http://example.com/request may be followed by a
GET http://evil.com/request on the same connection. If we start to ignore the connection after the first request, we would miss the relevant second one.