The company has a long involvement in the collaborative software movement. It sells proprietary software that works with a popular open-source component, also called Sendmail, used to transfer e-mail from one server to another.
Itto open source, and Eric Allman, the original developer of the software and Sendmail's chief science officer, gave an update on the plans this week.
Sendmail iswhich parts of its Mailcenter suite of products to open source, said Allman. Mailcenter Quarantine, a facility for queuing, reviewing, and taking action on quarantined messages, has come under close scrutiny.
"I personally think Mailcenter is a strong candidate," said Allman. "We're looking at the legal implications at the moment. Some code (in Mailcenter) has been bought, some has been licensed. It was so long ago--six or seven years--we've asked our lawyer to dig through the paperwork," Allman told ZDNet UK.
The company is also in the process of deciding which parts of Mailstream Manager, an engine that sorts mail according to policies and accepts security and compliance plug-ins, to release under an open-source license.
Allman said that deciding which parts of the company's code base to open source was a complex process.
"Now I understand why companies have such trouble open sourcing--you use this, and license that. We are a commercial company, so our lifeblood is profit. We have to be careful not to shoot ourselves in the foot by giving away all of our code," said Allman.
"Some things we can't open source. For example, we use antivirus engines from McAfee and Comtouch. They probably wouldn't be happy if we gave away their software," Allman added.
By going open source, Sendmail may achieve greater renown and broader adoption for its products.
"You get a certain amount of cachet. The more people that know about your stuff, the better," said Allman back in April. Broader use of open-source components helps sales of accompanying proprietary software, he said.
For another, outsiders can provide ideas and find bugs, sometimes supplying source code along with the information.
Sendmail is very wary of copyright infringement, but is more worried that it could be sued by patent holders.
"Copyright is a big issue, especially if you have code from a partner integrated into your code. Often licence agreements only let you use the binary code," said Allman.
"Patent law is stickier. It's an ugly area the whole industry has to deal with. It seems it's difficult to write code today without standing on someone's toes.... It's crazy! You do something that seems obvious and 10 years later someone comes and asks for a backlog of licence fees--that's scary!" said Allman.
Another candidate for open-source licensing is the LDAP code that underlies ECOSys Directory, an information retrieval solution.
"That actually started as open-source code. I personally like (this candidate) because it would give something back to the community--but ultimately it's not my decision," said Allman.
Sendmail has also been "quietly open sourcing" some of its code, including the mail filter plug-in to Sendmail, Milter, and DomainKeys Identified Mail, an authentication protocol for which Allman was the lead editor on the base signature standard.
CNET News.com's Stephen Shankland contributed to this report.
Tom Espiner of ZDNet UK reported from London.