On 6/25/2010 10:06 AM, Mark Krenz wrote:
Hi, this is more of a policy type of question, but I'm not sure who else to ask right now. We are a small webhosting/email hosting provider. We offer our clients authenticated SMTP relaying. One of our clients is complaining because we don't strip out the first Received header line that shows what their company IP address is when they send from say their Outlook client. They are claiming that as a proper hosting provider, we shouldn't be keeping that line in. They also think that because we leave that in that they are having their IP put on blacklists. So I'm wondering if that's true, have modern email relay server practices changed for some reason? Am I going to run into issues leaving it in? I looked around last night and found some pages talking about how to strip that line out, but I couldn't find any pages recommending that this is the preferred practice now or something.
No, it is not common practice to strip out Received: headers, and is not recommended.
Some misconfigured spam filters check ALL received headers against RBLs, causing false rejects. If your customer frequently communicates with such a host, you may need to a) contact the postmaster at the recipient domain and explain their error and when that doesn't work you may need to b) remove or rewrite the header somehow -- examples are in the list archives.
Also note that some spam filters will add points for messages with no prior Received: headers, so sometimes you can't win either way.
-- Noel Jones
