Edit on GitHub

#  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 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 view_filter 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

The ignore_hosts option allows you to specify a regex which is matched against a host:port string (e.g. “example.com:443”) of a connection. Matching hosts are excluded from interception, and passed on unmodified.

command-line alias	--ignore-hosts regex
mitmproxy option	ignore_hosts

#  Limitations

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_hosts option 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.¹ The ignore pattern is applied on CONNECT requests, which initiate HTTPS or clear-text WebSocket connections.

#  Tutorial

If you just want to ignore one specific domain, there’s usually a bulletproof method to do so:

1. Run mitmproxy or mitmdump and observe the host:port information following the server connect messages in the event log. mitmproxy will filter on these.
2. Take the host:port string, surround it with ^ and $, escape all dots (. becomes \.) and use this as your ignore pattern:

>>> mitmdump
Proxy server listening at http://*:8080
127.0.0.1:57089: client connect
127.0.0.1:57089: server connect example.com:443 (93.184.216.34:443)
127.0.0.1:57089: GET https://example.com/ HTTP/2.0
     << HTTP/2.0 200 OK 1.23k
127.0.0.1:57089: client disconnect
127.0.0.1:57089: server disconnect example.com:443 (93.184.216.34:443)
^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:'

# Transparent mode:
--ignore-hosts 17\.178\.96\.59:443
# IP address range:
--ignore-hosts 17\.178\.\d+\.\d+:443

If you want to capture some specific domains only, you can use the --allow-hosts option, which makes mitmproxy ignore all other traffic.

---

1. 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. ↩︎