User Guide

40-21
AsyncOS 9.1.2 for Cisco Email Security Appliances User Guide
Chapter 40 Testing and Troubleshooting
Troubleshooting the Network
The tophosts command returns a list of the top 20 recipient hosts in queue. This command can help
you determine if network connectivity problems are isolated to a single host or group of hosts to
which you are attempting to send email. (For more information, see “Determining the Make-up of
the Mail Queue” on page 49.)
• “Drill-down” to use the hoststatus command on the top domains listed from the tophosts
command results.
The
hoststatus command returns monitoring information about email operations relating to a
specific recipient host. DNS information stored in the AsyncOS cache and the last error returned
from the recipient host are also given. Data returned is cumulative since the last
resetcounters
command. (For more information, see Monitoring the Status of a Mail Host, page 34-11.)
Using the
hoststatus command on the top domains can isolate the performance issues with DNS
resolution to the either the appliance or the internet. For example, if the
hoststatus command for
the top active recipient host shows many pending outbound connections, then try to determine if that
particular host is down or unreachable, or if the appliance cannot connect to all or the majority of
hosts.
mail3.example.com> tophosts
Sort results by:
1. Active Recipients
2. Connections Out
3. Delivered Recipients
4. Soft Bounced Events
5. Hard Bounced Recipients
[1]> 1
Status as of: Mon Nov 18 22:22:23 2003
ActiveConn.Deliv.SoftHard
# Recipient HostRecipOutRecip.BouncedBounced
1 aol.com36510255218
2 hotmail.com29071982813
3 yahoo.com13461231119
4 excite.com9838494
5 msn.com8427633 29
^C