XITRON XT2640 - Page 133

XT2640OperatingManual 13July2016 Page133of187
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TheXT2640doesnotsupportgeneratingVLANtraffic,andalthoughitcanreceiveVLANformattedtrafficitignoresthe
VLANinformation.IfusedonanetworkwhichusesVLANthenitshouldbelocatedonaportionofthatnetworkwhich
doesnothavetheVLANcontent.CheckwithyourITdepartmentregardingthisifnecessary.
24.1.2.3 CONCERNSREGARDINGSE CURITYUSINGTHEXT2640VIALAN
YoumaybeconcernedwiththesecurityofyournetworkwhenconnectingaXT2640toit.Suchaconcernisgenerallyunnecessary
astheXT2640isnotcapableofanytransfersthatcandetrimentallyaffectotherequipmentorcomputersonthenetwork.
Additionally,theXT2640canbeconfiguredforAuto‐IP(RFC3927)IPaddressing.InthatcasenotraffictoorfromtheXT2640
shouldbeabletopassthrougharouter,sotheXT2640canbemadetobelocaltoaportionofanetwork.
Note:
TheXT2640generallyhasabenignpresenceontheLANanddoesnotbroadcastanytrafficrelatedtoitspresenceonthe
LAN(otherthanDHCPtrafficifenabledandARPtrafficasneeded).
TheXT2640onlysupports–
TheDHCPProtocol(onlyifconfiguredtouseDHCP).
TheARPprotocol(onlytoensuretheuniquenessofitsownIPaddress,andasnecessarytoconfirmthepresence
ofthecomputerwhichhasaTCP/IPsocketestablishedtotheXT2640,theXT2640doesnotarbitrarilygenerate
ARPrequests).
TheICMPreceptionofa‘ping’andthetransmissionofitsresponse(itcannotgeneratea‘ping’).
IftheXT2640isconfiguredtohaveanIDENTITYnamethenthisisverifiedasbeinguniqueusingmDNSwhenthe
XT2640isturnedon,orjustconnectedtotheLAN,ortheidentitynameischanged.Theidentitycapabilitymay
bedisabledtoremovethecapabilityofgeneratingmDNStraffic.
TransferofASCIIdatafromtheXT2640toacomputerusingstreamingTCP/IPprotocoltowhichithasaTCP/IP
socketestablishedonlywhenandasdirectedbythatcomputer(onlyasinglesocketisallowedbytheXT2640).
DatatransmittedfromtheXT2640canonlybemeasurementresultsandmeasurementstatusinformation.These
areallnon‐broadcastdatagrams,soinawell‐designednetworkthesedatagramswillnotbetransmittedbeyond
theconnectionbetweenthecomputerandtheXT2640.
AllLANpacketsreceivedwhicharenotsupportedaresilentlydiscardedandignored.
TheXT2640doesnotsupport–
CommunicationswithacomputerwithwhichitdoesnothaveaTCP/IPsocketestablished(whichcanonlybe
establishedbythecomputer,notbytheXT2640).
ReceptionofanybroadcastrequestsotherthanDHCP(onlyifenabled)andARP(allotherreceivedbroadcasts
aresilentlyignored).
TransmissionofanybroadcastpacketsotherthanDHCP(onlyifenabled)andARP(onlyasrequiredtoensurethe
uniquenessofitsownIPaddress).
Transportinganybinarydata.
AnynetworkmanagementprotocolssuchasSNMP,SSDP,LLDP,SDP,CDPetc.,orroutingprotocolssuchasRIP
etc.
Any‘filesystem’,NETBIOSorsimilarprotocols.
AnyHTTP,FTP,etc.whichmightenablea‘program’tobetransferredtoorfromtheXT2640viatheLAN.
AnyPOP,SMTP,IMAP,NetBIOS,NetBT,IPXorsimilarprotocolswhichmightestablishaconnectiontoanother
computer.
24.1.2.4 WRITINGSOFTWARETOCONTROLTHEXT2640VIALAN
AllcommunicationwiththeXT2640usesTCP/IPport10733intheXT2640.TheXT2640onlyallowsoneactivesocketatanygiven
time,soyoushouldclosetheTCP/IPsocketwhenfinishedusingit.Toavoidunnecessarylockouts,theXT2640willallowa
replacementsocketifthepreviouslyactivesocketisstillopenbuthasnotbeenactivefor>1minute,inwhichcaseitwillclosethe
expiredsocket(thisonlyoccursifanewsocketisattempted,otherwisetheXT2640willkeepasocketopenevenifitisnotactive).
TCP/IPhasCRCerrorchecking,packetlossdetection,andautomaticretransmissionoflostorcorrupteddata.Thismeansthatthe
userneednotperformerrorcheckingusingcommandssuchas*ERR?whenusingtheLANinterfaceexceptfortestingyoursoftware,
aseachcommandisguaranteedtoreachtheXT2640withouterror.
BeforeyoursoftwarecancommunicatewiththeXT2640itgenerallymustcreateanobjectforthesocketandthenconfigureand
openit.
Dim enet_socket As System.Net.Sockets.TcpClient
enet_socket.Connect(System.Net.IPAddress.Parse(EnetIPAddrBox.Text), 10733)
enet_socket.ReceiveTimeout = 1000
Toclosethesocketthefollowingisanexample.
enet_socket.Close()
TheexampleaboveshowsusingtheIPaddressofaXT2640toopenaconnectiontoit.AlternativelytheidentitynameoftheXT2640
canused,butwith‘.local’appendedtotheendofit,asanexampleiftheXT2640identityisXT2640‐123456thenasocketwithitcan
beopenedusing–
enet_socket.Connect(“XT2640-123456.local”, 10733)
OpeningasocketusingtheidentitynamehastheadvantagethatyoudonotneedtoknowtheIPaddressoftheXT2640,onlyits’
identityname,soyoursoftwaredoesnotneedtobemodifiedtoaccommodatechangestothenetworkconfiguration.