Firewall considerations for additional channel keywords:
deferred channel keyword is discussed in
Section 2.3.4.19 ; note that use of this keyword allows users to use the
PMDF system's e-mail disk space as an extension of their own disk
space. The default behavior of nodeferred is likely
particularly appropriate behavior for an e-mail firewall if you are
concerned about preventing a denial of service attack on your disk
space.
maxprocchars channel keyword causes PMDF to not
bother processing addresses in headers over the specified number of
characters; in such a case PMDF passes the unprocessed headers through
unchanged. See Section 2.3.4.78 for details.
network rightslist identifier requires
users of the channel to have the NETMBX privilege; see Section 2.3.4.89
for details.
nonurgentblocklimit,
normalblocklimit, and urgentblocklimit
channel keyword can be used to set thresholds for when to downgrade
message priority. Message priority, in turn, may affect whether PMDF
attempts to send a message immediately, or whether PMDF lets the
message wait until the next time the PMDF periodic delivery job runs.
Depending upon your needs and circumstances, having large messages wait
on the firewall system until a periodic job runs may be either
beneficial, by not using resources that could be used to send small
messages immediately, or may expose your firewall system to the
potential for getting its disk space "clogged up" with
pending large messages in between runs of the periodic job.
nox_env_to channel keyword, which is the default,
ensures that no X-Envelope-to: headers are put on messages. If you are
using centralized naming, this is likely a particularly appropriate
default. The x_env_to channel keyword, on the other hand,
requests that PMDF include an X-Envelope-to: header.