Ports; Security Issues With Ports - ADDER AdderView CATxIP 1000 User Manual

Ports

If.you.accept.the.analogy.of.IP addresses.being.rather.like.telephone.numbers,.
then.think.of.ports.as.extension.numbers..In.a.company.of.any.size,.you.
generally.wouldn't.expect.the.accounts.department.to.share.the.same.telephone.
with.the.technical.department..Although.their.calls.may.all.be.related.to.the.
same.company,.they.concern.very.different.aspects.of.that.company..
It.is.the.same.with.IP.network.connections..Although.you.have.only.one.network.
link.into.your.computer.and.only.one.IP.address.(phone.number),.you.are.
probably.performing.many.different.tasks.through.that.one.link,.often.at.the.
same.time..Thus,.when.you.browse.the.web.your.outgoing.requests.and.the.
incoming.information.are.all.channelled.through.port.80..When.you.send.an.
email,.it.travels.through.port.25.and.when.you.transfer.files.you.are,.without.
knowing.it,.using.port.20.
At.the."border.crossing".between.the.wider.Internet.and.every.local.network.
attached.to.it,.there.is.a.router.that.is.usually.combined.with.a.firewall..One.of.
its.main.tasks.is.to.direct.incoming.traffic.to.the.correct.place.within.its.local.
network..A.key.piece.of.information.to.help.it.do.this.is.the.port.number:.
Internet
User.accesses.the.company.
website.at:.129.7.1.10.(this.
automatically.uses.port.80)..
LOC REM VNC 100 LNK PWR
www.adder.com
AdderView.CATxIP.1000.
has.the.local.IP.address:.
192.168.0.3
User.with.VNC.viewer.accesses.
IP.address:.129.7.1.10.(this.
automatically.uses.port.5900)..
Router/firewall address: ...0
Router.is.programmed.to.send.port.5900.
VNC.traffic.to.local.address.192.168.0.3.
and.port.80.web.traffic.to.local.address.
192.168.0.42
.
Web server
Web.server.has.the.local.
IP.address:.192.168.0.42

Security issues with ports

The.settings.of.port.numbers.become.important.when.the.AdderView.CATxIP.
1000.is.situated.behind.a.network.firewall..In.order.for.a.remote.VNC.viewer.or.
web.browser.to.make.contact.with.your.AdderView.CATxIP.1000,.it.is.necessary.
for.the.firewall.to.allow.communication.through.a.particular.numbered.port.to.
occur..
One.specific.function.of.firewalls.is.to.restrict.access.to.ports.in.order.to.prevent.
malicious.attackers.using.them.as.a.route.into.your.network..Every.new.port.
that.is.opened.offers.a.new.possibility.for.hackers.and.so.the.number.of.
accessible.ports.is.purposefully.kept.to.a.minimum..In.such.cases,.it.may.be.
advantageous.to.change.one.or.both.AdderView.CATxIP.1000.ports.to.use.the.
same.number..The.other.alternative.is.to.place.the.AdderView.CATxIP.1000.unit.
outside.the.firewall.and.take.full.advantage.of.its.secure.operation.features.–.see.
Networking issues.for.details.
IMPORTANT: The correct configuration of routers and firewalls requires
advanced networking skills and intimate knowledge of the particular network.
Adder Technology cannot provide specific advice on how to configure your
network devices and strongly recommend that such tasks are carried out by a