One of the things I've learned the hard way in writing Unix programsis that you should almost never expect to know all of the errno valuesthat system calls can return. In theory it's documented in themanpages, but in practice a manpage's list is never comprehensive.The safest thing to do is to assume that any system call can returnalmost any errno value.

The example I remember most vividly is that our SMTP server daemonused to carefully check the result of accept() . If

This week we received 12,785 email messages from 208 different IPaddresses. Our SMTP server handled 17,958 sessions from 984 differentIP addresses. Session volume is dramatically down from the levels of last week .

Connection volume is also down: 122,600 connections from at least44,760 different IP addresses. However, we hit a highwater mark of 50connections being processed at once on Tuesday, so we have had

This is one of those amusingly creative mistakes to see in action:

• microsoftglobal.com lists as nameservers ns1.one-dom4.com andns2.one-dom4.com.
• both respond with errors if they are sent queries that allowrecursion.
• sent queries marked non-recursive, both answer all DNS queries forthe domain with no actual data, but with an 'additional authority'section that says they're the nameservers for the domain.

Nameservers normally answer a query for a domain they

The other day a weblog I read had a post (and their RSS feed) blow up because of invalid markup: an entry wasquoting some text that had bare '<'s in it, nothing escaped them, andinvalid HTML tags got generated and ate part of the entry. (Theproblem's now been fixed.)

There's nothing noteworthy about this, and that's the problem: peoplemake this mistake all the time. HTML has a bunch of picky rules tokeep track of