Unable to Unlock Symantec AntiVirus Server Group
I was unable to unlock the server group on a Symantec AntiVirus Corporate
Edition 8.1 server. I was also unable to start the Symantec AntiVirus
Server service or update the virus definitions on the server.
I discovered the problem was due to corrupt virus definitions.
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Encoding Spaces in URLs
If you have a filename that includes spaces, you should encode the URL that you
use for any links to the document, i.e.
should be used wherever
a space occurs in the filename.
You can go to
URL Encoding to see a list of characters that should be encoded, such as the
space character. You can also plug in a URL there and have it converted to a browser
IP and Domain Name Reputation Sites
address may be added to a
DNS Blacklist (DNSBL)
, if spam
is detected as emanating from that IP address. You can check for the presence
of an IP address on various blacklists using the
MxToolBox Email Blacklist
, which currently checks 124 blacklists, or at individual
blacklist sites, such as
You can check on whether an IP address has been associated with attacks
on other systems at DShield
or myNetWatchman by
performing an IP lookup.
You can also obtain information on the "reputation" for a site
Central by performing a lookup on either an IP address or a domain name.
Barracuda Networks sells widely used spam firewall devices, so a poor
reputation listing at Barracuda Central may lead to email from an IP address
listed there, or with a domain name in the body of email messages being found
there, being blocked by those using Barracuda Networks security devices.
Another reputation site is
TrustedSource. You can lookup an IP address there and see a graph
of activity associated with that site. If you see red bars on the
graph, those represent malicious activity associated with the IP address
on the days for which those bars appear.
Locating Cybersquatters Capitalizing on a Variant of Your Domain
may buy domains similar to yours hoping to take advantage
of someone mistyping your domain name or to mislead someone into thinking
a domain name in a URL belongs to a legitimate company or organization.
For instance many people might visit microsoft.com, so a cybersquatter might
buy micrsoft.com, which has a missing "o", so that someone making a typo that
left out that "o" would be directed to the cybersquatter's site instead, where
the cybersquatter may have nothing but ads, hoping to get money generated
from those viewing those ads. If millions of people visit microsoft.com every
week, the cybersquatter will probably get a signifiant amount of traffic
from such a typo.
Or perhaps you own example.com. The cybersquatter may purchase example.net,
if it is available. Someone seeing example.net in an email may think the
domain belongs to your company and visit a site that might have nothing but ads,
perhaps even risque ones, or the site might try to infect visitors with
adware/spyware, which might harm your company's reputation, even though you
don't own the domain name and have no control over the site.
CitizenHawk helps you locate
potential cybersquatter sites for your domain name.
Configure Sendmail to Listen on All Addresses
If you can't connect to the
port on a system, i.e.
port 25, from external hosts, but you can connect from the system itself,
then you need to comment out a line in
restricts connections to the local loopback address, 127.0.0.1.
I.e., if you can use
telnet 127.0.0.1 25 and see the sendmail
banner, but when you use
telnet 192.168.0.44 25 (presuming
192.168.0.44 is the IP address for the mail server), you get "connection
refused" messages, then the default configuration option in
sendmail.mc is likely preventing the connection by causing
sendmail to only listen on the loopback address.
# telnet 192.168.0.44 25
telnet: connect to address 192.168.0.44: Connection refused
telnet: Unable to connect to remote host: Connection refused
To resolve the problem, look for the following lines in
, which on a Linux system will likely be in the
dnl # The following causes sendmail to only listen on the IPv4 loopback address
dnl # 127.0.0.1 and not on any other network devices. Remove the loopback
dnl # address restriction to accept email from the internet or intranet.
sendmail.mc file from the root account. Put a
dnl # at the beginning of the
line to comment out the line.
dnl # DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl
Then issue the following commands:
m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf
The first command rebuilds the .cf configuration file from the modified
.mc file. The second restarts sendmail so that it is using the new