Hey dude, is your #550 cataddr: string too long?

Are you experiencing delivery problems from your Exchange 2007 servers to IBM.com and other sites using Sendmail 8.x? Is the error "#550 cataddr: string too long" being returned when users try to send to certain domains?

The problem (as worked through by our colleague Brian at SUNY Canton with HP Support) was tracked down to be a TLS negotiation issue between Exchange and Sendmail. Apparently there is a fix for Sendmail, but if you're running as an admin on the Exchange side, you'd rather not have to contact all the Sendmail site admins that you exchange email with and have them "fix" their systems.

Read on for a workaround from Brian, as well as a thought that I had for an alternate solution.

Brian's Solution from working with HP Support:
Set-SendConnector "Internet" -IgnoreStartTLS $true
Sets the default "Internet" send connector for ALL internet mail to ignore TLS negotiation.

My Alternate Suggestion:
Create a custom send connector that will be used for ibm.com (and other domains that are deemed problematic to this issue) and turn off TLS negotiation for that connector only. Other domains that are found to exhibit the same problem can easily be added to the custom connector via the Exchange Management Console (or through Powershell) when discovered.

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