Multi-Tech Systems S000573A Settingupfirewalls

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UsingtheRouter’sWebInterface  22
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Settingupfirewalls
Definingfirewallrules
Therouter'sfirewallenforcesasetofrulesthatdeterminehowincomingandoutgoingpacketsarehandled.
Bydefault,alloutboundtrafficoriginatingfromtheLANisallowedtopassthroughthefirewall,andall
inboundtrafficoriginatingfromexternalnetworksisdropped.Thiseffectivelycreatesaprotectivebarrier
betweentheLANandallothernetworks.
Addingforwardingrules
ForadevicewithintheLANtobevisiblefromtheinternetorfromanoutsidenetwork,createaforwarding
ruletoallowincomingpacketstoreachthedevice.
1. InthePortForwardinggroup,clickAddRule.
2. Enteranameanddescription.ClickNext.
3. IntheIPForwardingDNATpane,enterthefollowing:
 IntheExternalWANPortsfield,typetheport(s)tobeforwarded.Commonportsarelistedinthe
field'sattacheddrop‐downlistandareexposedonceyouenteracharacter.TypeANYtoforwardall
ports.
 IntheDestinationLANIPfield,typetheIPaddressofthedevicepacketswillbeforwardedto.The
attacheddrop‐downlistcontainsDHCPleasedandSavedNetworkaddresses.
 IntheDestinationLANPortsfield,typetheporttowhichpacketsaretranslated.Ifthereisarangeof
ports,theendingportisautomaticallyset.TheDestinationLANendingportisbasedonthe
DestinationLANstartingportandtherangeprovidedintheExternalWANPort(s)field.
 FromtheProtocoldrop‐downlist,selecttheprotocolofthemessagesthatcanbeforwarded.
 Adefaultfilterallowingforwardedpacketsthroughthefirewallisautomaticallycreated.Ifdesired
youcanusetheAdvancedSettingmodeofthePortForwardingwizardtofurtherrestrictpackets
basedonsourceaddressandsourceports.Inmostcasesthisisnotnecessary.
4. ClickFinish.
AddingOutboundTrafficRules
TopreventadevicewithintheLANfromcommunicatingwithadeviceinanexternalnetwork,arulehastobe
establishedinthefirewalltodroppacketsdestinedtotheexternaldevice.
1. ClickAddRuleintheOutboundTrafficsection.
2. Enteranameanddescription.ClickNext.
3. IntheDestinationIPfield,typetheIPaddressofthedeviceornetworkpacketsarebeingsentto.Type
ANYifthedestinationaddressdoesnotmatter.
4. IntheDestinationMaskfield,typethenetworkmaskofthedestinationnetwork.
5. IntheDestinationPortfield,typetheportpacketsaredestinedfor.Commondestinationportsare
listedintheDestinationPortfield'sattacheddropdownlist.TypeANYifthedestinationportdoesnot
matter.
6. IntheSourceIPfield,typetheIPaddressofthedeviceornetworkthatthetrafficoriginatesfrom.Type
ANYifthesourceaddressdoesnotmatter.
7. IntheSourceMaskfield,typeanetworkmaskfortheoriginofthetraffic.