TLS question about encryption (cipher)

[khuul]

I have STARTTLS enabled in Sendmail. In the log, when I received mail from my partner, I see this:

Oct 15 09:09:40 mail mail:info sendmail[33326]: STARTTLS=server, relay=x.x.x.x, version=TLSv1/SSLv3, verify=OK, cipher=RC4-SHA, bits=128/128

When I send mail to my partner, I see this in the log:

Oct 15 09:12:02 mail mail:info sendmail[4562013]: STARTTLS=client, relay=x.x.x.x, version=TLSv1/SSLv3, verify=OK, cipher=DHE-RSA-AES256-SHA, bits=256/256

My question is, the CIPHER indicates RC4-SHA when I receive mail, but it uses DHE-RSA-AES256-SHA when I send mail to them.

Is the CIPHER encryption method offered by the client (STARTTLS=server) when they send mail to me? Or is it offered by my mail server?