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Can software firewalls and security packages cause problems?


I can’t access this website…

I’m not seeing pictures in my email…

Emails are disappearing from my inbox…

This program’s not working…

Why am I getting all these warnings…

I can’t get a video / audio / instant messaging connection…

Those are all extremely common questions I get every day.

And, while it’s definitely not the case that a software firewall or
security package is always the cause, it turns out to be fairly common.

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Based on the number of reports I get, many of these types of problems, and
others, often go away when a software firewall or security package is disabled
or reconfigured in some way.

And it’s almost always the more full featured software firewalls or Internet
security suites that cause the problem.

Let’s look at each of the symptoms I listed, and how a these packages might
be interfering.

I can’t access this website…

Security packages will sometimes block access to certain websites or IP
addresses that are known to cause problems. However, apparently, sometimes the
database of sites or IPs that the software uses can get confused, or sites can
get mistakenly blocked.

The good news here is that a good package will have a “whitelist” – a way to
specify that it should ignore what it thinks it knows, and allow you to go to a
specific site or IP anyway.

I’m not seeing pictures in my email…

Many firewalls and security packages have features designed to help protect
you from malicious emails. One way that email can sometimes be used to infect
or harm your computer is through vulnerabilities in image display, or using
remote images to track whether or not you’ve opened the message. Sometimes it’s
the images themselves, while technically “safe”, that are offensive in some
way. The security packages simply block images using some rules to try and
guess what’s ok and what’s not.

Sometimes the rules are wrong.

Again, the software should have a way of specifying that images under these
conditions – typically from specific addresses, or from contacts in your
address book, are safe and should be displayed.

Emails are disappearing from my inbox…

This one happens a lot due to over-aggressive spam filtering. Many security
programs hook into the email program, or email network traffic, in order to
scan for viruses, spyware, phishing schemes and what have you. Unfortunately,
sometimes they simply get it wrong, cause problems in the email program you
use, or simply cause email to disappear. Outlook Express users appear to be
particularly vulnerable to corruption. This is often difficult to control once
diagnosed. Most definitely pay attention to the email related settings of the
package you’re using, and see if it can be turned off or “dialed down” a

This program’s not working…

Many programs that access the internet will have problems if a firewall or
other security package inserts itself into the middle of the communication.
Sometimes it’s a simple technical problem, other times it’s the security
software interfering with or modifying the actual data stream. At times this
can even happen due to anti-virus programs watching what’s being written to
your hard disk. In almost all cases diagnosis is very difficult; while turning
of the security software completely might provide a good clue that it’s related
to the problem, what to do next is often unclear. The best bet is to take the
specifics of the situation to the support options offered by the manufacturer
of the security package you’re running.

“Based on the number of reports I get, many of these
types of problems, and others, often go away when a software firewall or
security package is disabled …

Why am I getting all these warnings…

ZoneAlarm in particular, but similar software firewalls as well, are
designed to monitor communications that originate from your computer as well as
incoming issues, as opposed to the Windows firewall and NAT routers which
primarily protect you from external threats. Apparently some times ZoneAlarm
can be configured to tell you about every little thing that’s going on, and can
just flood you with warnings – typically in terms that are difficult to
understand. Simple things like Windows attempting to synchronize your clock can
cause pop up messages, which are totally safe to ignore – if you know that’s
what’s happening.

If you’re facing this problem and getting many more warnings than you know
what to do with, you’ll probably want to take some of those specific warnings
over to the ZoneAlarm support site (or the support site for whichever software
firewall you’re using) and

  • determine if the warning is a legitimate problem, or a benign message

  • if benign, learn how to configure the firewall to allow it to pass without

I can’t get a video / audio / instant messaging

Many firewalls block a wide range of incoming ports by default.
Unfortunately, while the ports for common text messaging are typically open,
quite often the ports used for more advanced features such as audio and video
are blocked by default.

First, you’ll need to determine which ports are required to support the
feature you’re using in the IM client you’re using. (Personally, I like the
forums out at Big Blue Ball
for most all IM client information.) Once you know the ports needed, you’ll
need to determine how to open your particular firewall, or in the case of a
router, how to forward those ports to the appropriate computer. Depending on
your situation, this can either be very easy, or quite complex.

Software firewalls and security suites most definitely have their place in
keeping the internet, and you machine, safe. Unfortunately they can also inject
their own flavor of problem if not configured properly. A quick test to see if
the firewall or security software is at fault is, of course, to turn it off.
What happens next depends entirely on the original issue, and the specifics of
your situation. Because these are often not new issues at all to the
manufacturers or other users of these security tools, your best bet once you’ve
made that determination, is to visit their support site and public forums. Nine
times out of ten, your answer will be there.

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6 comments on “Can software firewalls and security packages cause problems?”

  1. my son runs the router for our computers and i cannot get deer hunter 2005 to go on line as host game spy has to run and it gets blocked any help???

  2. I have a rather unique problem (I think). I play a game from (Pengapop) for fun. When I use IE (6 or 7) the game loads properly and allows me to play. The same is true for Outlook Express. However, when I try to use the AOL browser (based on IE, I understand) it will not allow me to play the game. Throws up a complaint about me not having a certain Shockwave update or something. Wants me to download it. Asking AOL techs for help got me a long, long process to use, but that did not work either. The question is, then: how come these other browsers can find the correct Shockwave, but AOL can’t; and what can I do (other than not use AOL) to fix this issue?

  3. The AOL browser is crippled in some respects. Your best bet, as you’ve already discovered, it to use the regular version of IE.

  4. I’m having a “slow computer” problem, so I read the comments on firewall and security problems. One of the suggestions was to “check the registry”. One of the FREE programs on the site was UNIBLUE from – I ran the free scanner and it turned up a bunch of errors. I subscribed for the program, and somehow managed to foul up the transmission. THERE IS NO WAY TO CONTACT UNIBLUE other than email – and they are very busy..I have emailed several times for help and they say “when they have time”. Just a “heads up” about UNIBLUE!

  5. There is one more answer, the HOSTS file. The hosts file bypasses DNS lookup of numeric IP addresses for alphabetical addresses.

    Some malware will put entries in HOSTS file to directing your browser to wrong location.

    Other possible problem is if you use a “blacklist” service that provides you with a HOSTS file that identifies and blocks malware sites. Some of these services also block web advertising to speed up your browser. Sometimes you may want to get to sites that they have decided to block. You have to manually edit the HOSTS file to delete the entry. These services provide frequent updates to the files. It is easy to forget that you have this service enabled when you can’t get to a specific site.

  6. Dear Leo and community!
    Zonealarm is the toughest and I would say best internet security software BUT it drives me up the wall!! After downloads the updates for spy and antivirus it becomes impossible to handle !!
    Meaning it locks up my pc and becomes awfully slow.Finally I got rid of it trying to deal with it for years.Now I feel vulnearable.No firewall ,no AV (forget norton or Mccafee they are worthless) is there anything else that is equal or better then zonealarm?
    PS: I’ve been an internet security wiz many years constantly monitoring the network activity I exactly know what ad agencies trying to steal and what.


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