Technote Number: 1102680
Dispatching messages means that Router is scanning messages waiting to be
transferred. Router is looking at each destination Internet domain and
obtaining the appropriate MX information from DNS before rebuilding the routing
tables. During this operation no messages are transferred.
The message "Dispatching messages (3900 dispatched)" indicates that Router is
performing the "dispatching" operation.
To verify events, add the following parameters to NOTES.INI:
These parameters produce information about the length of the reenum(eration)
process. Router performs two different reenumeration processes: reenum=0 and
reenum=1. After reenumeration is completed, mail transfer occurs.
Reenumeration uses one of two values: reenum=0 or reenum=1.
reenum=0. This reenumeration occurs frequently (up to several thousands of
times per hour) and allows messages to be transferred. It is normally a very
fast process; however, even when it takes several minute to complete, it does
not impact Router performance. It is a normal condition. Only new messages
needs to be checked. For example:
"Router: Dispatch took 94ms (reenum = 0)"
reenum=1. This process takes a longer time and is usually performed
infrequently. Router needs to rebuild the routing tables from scratch, check
every message that is pending transfer, note all the Internet domains of the
recipients, and perform a DNS lookup to obtain information from MX records for
the different domains. During this process, no messages are transferred;
instead, messages are transferred after this process is complete. If several
thousand messages are pending and with multiple recipients in many different
domains, this process can take from several minutes to an hour. The duration
of this process depends on several factors, such as, the speed at which DNS
responds to requests, and the server's resource load, CPU, and disk speed. For
"Router: Dispatch took 1220782ms (reenum = 1)"
The "reenum=1" process is performed under the following conditions:
When Router is restarted.
When Router detects a change in the Configuration document.
By default, every 60 minutes after the last reenumeration; or per the interval
set in the "Dynamic cost reset interval" field (in the Configuration document's
Router/SMTP, Advanced, and Controls tab, and Advanced Transfer Controls
To prevent "reenum=1" from occurring too frequently on a Domino 5.0.8x or
earlier server, do not modify the Configuration document too frequently. After
each modification of the Configuration document, Router initiates the
"reenum=1" process, resulting in an extended interval before mail is
This issue of Router not transferring mail for an extended time after the
Configuration document has been modified was reported to Lotus Software Quality
Engineering and has been addressed in Domino 5.0.9.
Excerpt from the Lotus Notes and Domino Release 5.0.9 MR fix list (available at
Mail Server - Router
SPR # IDEA4WMNS5 - Modified the behavior of the mail router to initiate any
possible transfers while re-enumerating a large number of pending mail.
If NSLOOKUP fails to successfully resolve DNS queries, Router on Domino 5.0.9x
and earlier servers is also slowed down. Examples of scenarios that result in
a slower performance by Router are the following: DNS is non-responsive or
exhibits a delayed response; and mail is addressed to Internet domains for
which there are no entries in DNS (no MX record is associated with the
domain). These scenarios can result in the following errors:
"Router: res_send failure DNS resolver error
Router: Unable to resolve destination domain XXYYZZ.COM; DNS is unavailable,
message will be requeued."
The above issue was reported to Lotus Software Quality Engineering and has been
addressed in Domino 5.0.10.
Excerpt from the Lotus Notes and Domino Release 5.0.10 MR fix list (available
SPR# IDEA525NJR - Implemented the storing of names of failed Domain lookups in
the router cache for a specified time by setting the notes.ini parameter,
The value of 1800 in the above example is in seconds; 1800 represents the
number of seconds to keep the failed domain in cache. By default, the
parameter is disabled; therefore, only successfully-resolved domain lookups are
added to the cache. When this parameter is enabled, the first time and
subsequent times that Time to Live (TTL) expires still consumes dispatch time;
however, repeated lookups of the same unresolved domain within the TTL returns
the previous error status instantly, thereby, allowing mail transfer to occur
The "Dynamic cost reset interval" field is located in the Configuration
document's Router/SMTP, Advanced, and Controls tab, and the Advanced Transfer
"DNS Resolver Error" Displays and No NRPC or OB SMTP Mail Routes
Document #: 1103128
What Does the INI Parameter MailMaxMessageQueue Do?
Document #: 1101355
Router Hangs (Doesn't Respond to Quit and Messages Pile up in MAIL.BOX)
w/Message Addressed to "@X
Document #: 1092360 More >