# Cert option ignores subdomain when used with wildcard certificate

**URL:** <https://discourse.mitmproxy.org/t/cert-option-ignores-subdomain-when-used-with-wildcard-certificate/1680>\
**Category:** help\
**Created:** [September 24, 2019, 12:03pm UTC](https://discourse.mitmproxy.org/t/cert-option-ignores-subdomain-when-used-with-wildcard-certificate/1680 "2019-09-24T12:03:00Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![nysos](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mitmproxy.org/nysos/32/488_2.png) [@nysos](https://discourse.mitmproxy.org/u/nysos)\
**Post date:** [September 24, 2019, 12:03pm UTC](https://discourse.mitmproxy.org/t/cert-option-ignores-subdomain-when-used-with-wildcard-certificate/1680/1 "2019-09-24T12:03:00Z")

</div>

I using the latest mitmproxy version (4.0.4) and try to achieve the following:  
a specific subdomain should be decrypted using a wildcard keypair I own for this domain (wildcard.pem), while all other subdomains should be intercepted using the default CA.

as such I use:  
`mitmweb --cert "sub.example.tld=./wildcard.pem"`

Expected behavior: the wildcard certificate is used for “sub.example.tld” while “www.example.tld”, “anothersub.example.tld” are intercepted using the mitmproxy CA.

What actually happens: all subdomains of example are intercepted with the wildcard cert I provide.

If i use a cert option with a non-wildcart certificate-keypair:  
`mitmweb --cert "works.example.com=./works.pem"`  
everything works as intended (mitmproxy CA is used for everything but [works.example.com](http://works.example.com)).

Any clues on what I am missing here?  
Is this intended behavior: “(wildcard) certificate CN overwriting specified subdomain”?