Underscore in Hostname

[Phil Pennock]

On 2006-07-26 at 21:15 +0000, jimbrett099 at comcast.net wrote:
> I know that it's technically not allowed by various RFCs but can
> cyrus handle underscores in a host name and, if so, how?

source, imap/lmtpengine.c, parseaddr()
There are two instances there of checking the syntax of a domain, once
under "/* at-domain-list */" and once under "/* @domain */".

Both look like:
 while (isalnum((int) *p) || *p == '.' || *p == '-') p++;
and for you need to look like:
 while (isalnum((int) *p) || *p == '.' || *p == '-' || *p == '_') p++;

That will get it accepted, but there may be other checks elsewhere in
the code.  I haven't looked, but the above should get you started.

I'm assuming that for such a large and important customer, you are able
and willing to document and maintain local patches.
-- 
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 In that order."  -- Gary Donahue