IPMonitor Module

Properties   Methods   Events   Config Settings   Errors  

The IPMonitor module is used to listen to network traffic.

Syntax

IPWorks.Ipmonitor

Remarks

The IPMonitor class will bind to a specific local host address and listen for network traffic received by the interface. The interface must support promiscuous mode (which may not work in many wireless cards because of security considerations) and must be installed on Windows 2000 or greater.

Note: If your computer connects to a switch, the switch will forward only those packets addressed to your computer. If your computer is on a hub, then you will receive everything.

The use of this component requires administrative permissions.

The first step in using the IPMonitor class is to set LocalHost to the IP address whose traffic you wish to monitor, and then set Active to True. For each packet that crosses the interface, the class will parse the header and fire an IPPacket event.

Property List


The following is the full list of the properties of the module with short descriptions. Click on the links for further details.

AcceptDataThis property enables or disables data reception (the IPPacket event).
ActiveThis property indicates whether the module is active.
IPPacketThis property includes the contents of the current packet.
LocalHostThe name of the local host or user-assigned IP interface through which connections are initiated or accepted.

Method List


The following is the full list of the methods of the module with short descriptions. Click on the links for further details.

ActivateThis method enables network monitoring.
ConfigSets or retrieves a configuration setting.
DeactivateThis method disables network monitoring.
DoEventsProcesses events from the internal message queue.
ListIPAddressesThis method lists the valid IP addresses for this host.
ParsePcapFileThis method parses the specified pcap file.
PauseDataThis method pauses data reception.
ProcessDataThis method reenables data reception after a call to PauseData .
ResetReset the module.

Event List


The following is the full list of the events fired by the module with short descriptions. Click on the links for further details.

ErrorInformation about errors during data delivery.
IPAddressThis event is fired for each valid IP address on this host.
IPPacketThis event is fired whenever a packet is received.

Config Settings


The following is a list of config settings for the module with short descriptions. Click on the links for further details.

ListInterfaceLists the interfaces visible to the WinPCap or NPCap driver.
ReceiveAllModeEnables a socket to receive all IPv4 or IPv6 packets on the network.
SelectedInterfaceUsed to select the interface the WinPCap or NPCap driver will listen on.
UseWinPCapWhether to use the WinPCap or NPCap driver.
AbsoluteTimeoutDetermines whether timeouts are inactivity timeouts or absolute timeouts.
FirewallDataUsed to send extra data to the firewall.
InBufferSizeThe size in bytes of the incoming queue of the socket.
OutBufferSizeThe size in bytes of the outgoing queue of the socket.
BuildInfoInformation about the product's build.
CodePageThe system code page used for Unicode to Multibyte translations.
LicenseInfoInformation about the current license.
MaskSensitiveWhether sensitive data is masked in log messages.
UseInternalSecurityAPITells the module whether or not to use the system security libraries or an internal implementation.

AcceptData Property (IPMonitor Module)

This property enables or disables data reception (the IPPacket event).

Syntax

public var acceptData: Bool {
  get {...}
  set {...}
}

@property (nonatomic,readwrite,assign,getter=acceptData,setter=setAcceptData:) BOOL acceptData;

- (BOOL)acceptData;
- (void)setAcceptData :(BOOL)newAcceptData;

Default Value

True

Remarks

This property enables or disables data reception (the IPPacket event). Setting this property to False temporarily disables data reception (and the IPPacket event). Setting this property to True reenables data reception.

Note: It is recommended to use the PauseData or ProcessData method instead of setting this property.

Active Property (IPMonitor Module)

This property indicates whether the module is active.

Syntax

public var active: Bool {
  get {...}
  set {...}
}

@property (nonatomic,readwrite,assign,getter=active,setter=setActive:) BOOL active;

- (BOOL)active;
- (void)setActive :(BOOL)newActive;

Default Value

False

Remarks

This property indicates whether the class is currently active and is monitoring network traffic.

Note: Use the Activate or Deactivate method to control whether the class is active.

IPPacket Property (IPMonitor Module)

This property includes the contents of the current packet.

Syntax

public var ipPacket: String {
  get {...}
}

public var ipPacketB: Data { get {...} }

@property (nonatomic,readonly,assign,getter=IPPacket) NSString* IPPacket;

- (NSString*)IPPacket;

@property (nonatomic,readonly,assign,getter=IPPacketB) NSData* IPPacketB;

- (NSData*)IPPacketB;

Default Value

""

Remarks

This property contains the contents of the current packet. This property is available only while the IPPacket event is being processed. An empty string is returned at all other times.

This property is read-only.

LocalHost Property (IPMonitor Module)

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

Syntax

public var localHost: String {
  get {...}
  set {...}
}

@property (nonatomic,readwrite,assign,getter=localHost,setter=setLocalHost:) NSString* localHost;

- (NSString*)localHost;
- (void)setLocalHost :(NSString*)newLocalHost;

Default Value

""

Remarks

The LocalHost property contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multi-homed hosts (machines with more than one IP interface) setting LocalHost to the value of an interface will make the class initiate connections (or accept in the case of server classs) only through that interface.

If the class is connected, the LocalHost property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multi-homed hosts (machines with more than one IP interface).

NOTE: LocalHost is not persistent. You must always set it in code, and never in the property window.

Activate Method (IPMonitor Module)

This method enables network monitoring.

Syntax

public func activate() throws -> Void
- (void)activate;

Remarks

This methods enables network monitoring. When called, the class will create a communication endpoint (socket) that can be used to monitor network traffic.

To stop monitoring traffic, call Deactivate.

Config Method (IPMonitor Module)

Sets or retrieves a configuration setting.

Syntax

public func config(configurationString: String) throws -> String
- (NSString*)config:(NSString*)configurationString;

Remarks

Config is a generic method available in every class. It is used to set and retrieve configuration settings for the class.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

Deactivate Method (IPMonitor Module)

This method disables network monitoring.

Syntax

public func deactivate() throws -> Void
- (void)deactivate;

Remarks

This methods disables network monitoring. When called, the class will stop monitoring network traffic.

DoEvents Method (IPMonitor Module)

Processes events from the internal message queue.

Syntax

public func doEvents() throws -> Void
- (void)doEvents;

Remarks

When DoEvents is called, the class processes any available events. If no events are available, it waits for a preset period of time, and then returns.

ListIPAddresses Method (IPMonitor Module)

This method lists the valid IP addresses for this host.

Syntax

public func listIPAddresses() throws -> Void
- (void)listIPAddresses;

Remarks

Use this method to list all valid addresses that can be monitored. Before monitoring the network, LocalHost must be set to a valid address on the host. After a call to this method, an IPAddress event will fire for each address.

ParsePcapFile Method (IPMonitor Module)

This method parses the specified pcap file.

Syntax

public func parsePcapFile(fileName: String) throws -> Void
- (void)parsePcapFile:(NSString*)fileName;

Remarks

This method parses the specified pcap (packet capture) file and fires events as if the traffic were received directly.

The class supports both the standard pcap and the newer pcap-ng file formats used by a variety of popular network capture tools. When calling this method, the file will be parsed and the IPPacket event will fire for each parsed packet.

PauseData Method (IPMonitor Module)

This method pauses data reception.

Syntax

public func pauseData() throws -> Void
- (void)pauseData;

Remarks

This method pauses data reception when called. While data reception is paused, the IPPacket event will not fire. Call ProcessData to reenable data reception.

ProcessData Method (IPMonitor Module)

This method reenables data reception after a call to PauseData .

Syntax

public func processData() throws -> Void
- (void)processData;

Remarks

This method reenables data reception after a previous call to PauseData. When PauseData is called, the IPPacket event will not fire. To reenable data reception and allow IPPacket to fire, call this method.

Note: This method is used only after previously calling PauseData. It does not need to be called to process data by default.

Reset Method (IPMonitor Module)

Reset the component.

Syntax

public func reset() throws -> Void
- (void)reset;

Remarks

This method will reset the class's properties to their default values.

Error Event (IPMonitor Module)

Information about errors during data delivery.

Syntax

func onError(errorCode: Int32, description: String)
- (void)onError:(int)errorCode :(NSString*)description;

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the class .

ErrorCode contains an error code and Description contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

IPAddress Event (IPMonitor Module)

This event is fired for each valid IP address on this host.

Syntax

func onIPAddress(ipAddress: String)
- (void)onIPAddress:(NSString*)ipAddress;

Remarks

Before monitoring the network, LocalHost must be set to a valid address on the host. Use the ListIPAddresses method to list all valid addresses that can be monitored. After a call to the method, an IPAddress event will fire for each address.

IPPacket Event (IPMonitor Module)

This event is fired whenever a packet is received.

Syntax

func onIPPacket(sourceAddress: String, sourcePort: Int32, destinationAddress: String, destinationPort: Int32, ipVersion: Int32, tos: Int32, id: Int32, flags: Int32, offset: Int32, ttl: Int32, checksum: Int32, ipProtocol: Int32, payload: Data, timestamp: Int64)
- (void)onIPPacket:(NSString*)sourceAddress :(int)sourcePort :(NSString*)destinationAddress :(int)destinationPort :(int)IPVersion :(int)TOS :(int)id :(int)flags :(int)offset :(int)TTL :(int)checksum :(int)IPProtocol :(NSData*)payload :(long long)timestamp;

Remarks

When Active is True or ParsePcapFile is called, the class will listen for network traffic or parse the provided file, respectively. For each packet sent across the interface in LocalHost, the class will parse the packet and fire an IPPacket event with the header fields and payload. The parameters are defined as follows:

SourceAddressThe IP address of the originating host in IP dotted format.
DestinationAddressThe IP address of the destination host in IP dotted format.
IPVersionThe IP protocol version being used by this packet.
TOSThe type of service being used by this packet.
IdThe packet Id used to identify and track packets.
FlagsFlags relating to the status of the packet and desired responses.
OffsetThe fragment offset of this packet in relation to larger data.
TTLThe time to live for this packet.
IPProtocolThe IP protocol used in the payload.
PayloadThe data field of the IP packet. This field may contain extra IP headers, depending on the IP protocol used to create it.
TimestampThis is the number of microseconds from the UNIX Epoch (1977-01-01). This is available only when parsing files.

TOS

Bit 0, 1, 2Precedence (see below)
Bit 3Delay (0 = Normal, 1 = Low)
Bit 4Throughput (0 = Normal, 1 = High)
Bit 5Reliability (0 = Normal, 1 = High)

Precedence

000Routine
001Priority
010Immediate
011Flash
100Flash Override
101CRITIC/ECP
110Internetwork Control
111Network Control

Flags

Bit 0Always zero
Bit 1Don't Fragment (0 = May Fragment, 1 = Don't Fragment)
Bit 2More Fragments (0 = Last Fragment, 1 = More Fragments)

IPProtocol (For a full list, visit www.iana.org.)

1ICMP
2IGMP
4IP
6TCP
17UDP

Config Settings (IPMonitor Module)

The class accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

IPMonitor Config Settings

ListInterface:   Lists the interfaces visible to the WinPCap or NPCap driver.

This configuration setting returns a numbered list of interfaces visible to the WinPCap or NPCap driver on the system.

ReceiveAllMode:   Enables a socket to receive all IPv4 or IPv6 packets on the network.

The following modes are available:

ValueDescription
0Do not receive all network traffic.
1 (default)Receive all network traffic. This enables the promiscuous mode on the network interface card (NIC). On a LAN segment with a network hub, the NIC that supports promiscuous mode will capture all IPv4 or IPv6 traffic on the LAN, including traffic between other computers on the same LAN segment.
2Receive only socket-level network traffic (this feature may not be implemented by your Windows installation).
3Receive only IP-level network traffic. This option does not enable promiscuous mode on the NIC. This option affects only packet processing at the IP level. The NIC still receives only packets directed to its configured unicast and multicast addresses. A socket with this option enabled, however, will receive not only packets directed to specific IP addresses, but also all of the IPv4 or IPv6 packets that the NIC receives.
ReceiveAllMode captures only IPv4 and IPv6 packets. It will not capture other packets (e.g., ARP, IPX, NetBEUI packets) on the interface.
SelectedInterface:   Used to select the interface the WinPCap or NPCap driver will listen on.

Set this configuration setting to the index of the interface the WinPCap or NPCap driver will listen on. Indices can be returned by querying ListInterface.

UseWinPCap:   Whether to use the WinPCap or NPCap driver.

When set to True, the class will use the WinPCap or NPCap driver available on the system. The default is False.

Socket Config Settings

AbsoluteTimeout:   Determines whether timeouts are inactivity timeouts or absolute timeouts.

If AbsoluteTimeout is set to True, any method which does not complete within Timeout seconds will be aborted. By default, AbsoluteTimeout is False, and the timeout is an inactivity timeout.

Note: This option is not valid for UDP ports.

FirewallData:   Used to send extra data to the firewall.

When the firewall is a tunneling proxy, use this property to send custom (additional) headers to the firewall (e.g. headers for custom authentication schemes).

InBufferSize:   The size in bytes of the incoming queue of the socket.

This is the size of an internal queue in the TCP/IP stack. You can increase or decrease its size depending on the amount of data that you will be receiving. Increasing the value of the InBufferSize setting can provide significant improvements in performance in some cases.

Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when the class is activated the InBufferSize reverts to its defined size. The same happens if you attempt to make it too large or too small.

OutBufferSize:   The size in bytes of the outgoing queue of the socket.

This is the size of an internal queue in the TCP/IP stack. You can increase or decrease its size depending on the amount of data that you will be sending. Increasing the value of the OutBufferSize setting can provide significant improvements in performance in some cases.

Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when the class is activated the OutBufferSize reverts to its defined size. The same happens if you attempt to make it too large or too small.

Base Config Settings

BuildInfo:   Information about the product's build.

When queried, this setting will return a string containing information about the product's build.

CodePage:   The system code page used for Unicode to Multibyte translations.

The default code page is Unicode UTF-8 (65001).

The following is a list of valid code page identifiers:

IdentifierName
037IBM EBCDIC - U.S./Canada
437OEM - United States
500IBM EBCDIC - International
708Arabic - ASMO 708
709Arabic - ASMO 449+, BCON V4
710Arabic - Transparent Arabic
720Arabic - Transparent ASMO
737OEM - Greek (formerly 437G)
775OEM - Baltic
850OEM - Multilingual Latin I
852OEM - Latin II
855OEM - Cyrillic (primarily Russian)
857OEM - Turkish
858OEM - Multilingual Latin I + Euro symbol
860OEM - Portuguese
861OEM - Icelandic
862OEM - Hebrew
863OEM - Canadian-French
864OEM - Arabic
865OEM - Nordic
866OEM - Russian
869OEM - Modern Greek
870IBM EBCDIC - Multilingual/ROECE (Latin-2)
874ANSI/OEM - Thai (same as 28605, ISO 8859-15)
875IBM EBCDIC - Modern Greek
932ANSI/OEM - Japanese, Shift-JIS
936ANSI/OEM - Simplified Chinese (PRC, Singapore)
949ANSI/OEM - Korean (Unified Hangul Code)
950ANSI/OEM - Traditional Chinese (Taiwan; Hong Kong SAR, PRC)
1026IBM EBCDIC - Turkish (Latin-5)
1047IBM EBCDIC - Latin 1/Open System
1140IBM EBCDIC - U.S./Canada (037 + Euro symbol)
1141IBM EBCDIC - Germany (20273 + Euro symbol)
1142IBM EBCDIC - Denmark/Norway (20277 + Euro symbol)
1143IBM EBCDIC - Finland/Sweden (20278 + Euro symbol)
1144IBM EBCDIC - Italy (20280 + Euro symbol)
1145IBM EBCDIC - Latin America/Spain (20284 + Euro symbol)
1146IBM EBCDIC - United Kingdom (20285 + Euro symbol)
1147IBM EBCDIC - France (20297 + Euro symbol)
1148IBM EBCDIC - International (500 + Euro symbol)
1149IBM EBCDIC - Icelandic (20871 + Euro symbol)
1200Unicode UCS-2 Little-Endian (BMP of ISO 10646)
1201Unicode UCS-2 Big-Endian
1250ANSI - Central European
1251ANSI - Cyrillic
1252ANSI - Latin I
1253ANSI - Greek
1254ANSI - Turkish
1255ANSI - Hebrew
1256ANSI - Arabic
1257ANSI - Baltic
1258ANSI/OEM - Vietnamese
1361Korean (Johab)
10000MAC - Roman
10001MAC - Japanese
10002MAC - Traditional Chinese (Big5)
10003MAC - Korean
10004MAC - Arabic
10005MAC - Hebrew
10006MAC - Greek I
10007MAC - Cyrillic
10008MAC - Simplified Chinese (GB 2312)
10010MAC - Romania
10017MAC - Ukraine
10021MAC - Thai
10029MAC - Latin II
10079MAC - Icelandic
10081MAC - Turkish
10082MAC - Croatia
12000Unicode UCS-4 Little-Endian
12001Unicode UCS-4 Big-Endian
20000CNS - Taiwan
20001TCA - Taiwan
20002Eten - Taiwan
20003IBM5550 - Taiwan
20004TeleText - Taiwan
20005Wang - Taiwan
20105IA5 IRV International Alphabet No. 5 (7-bit)
20106IA5 German (7-bit)
20107IA5 Swedish (7-bit)
20108IA5 Norwegian (7-bit)
20127US-ASCII (7-bit)
20261T.61
20269ISO 6937 Non-Spacing Accent
20273IBM EBCDIC - Germany
20277IBM EBCDIC - Denmark/Norway
20278IBM EBCDIC - Finland/Sweden
20280IBM EBCDIC - Italy
20284IBM EBCDIC - Latin America/Spain
20285IBM EBCDIC - United Kingdom
20290IBM EBCDIC - Japanese Katakana Extended
20297IBM EBCDIC - France
20420IBM EBCDIC - Arabic
20423IBM EBCDIC - Greek
20424IBM EBCDIC - Hebrew
20833IBM EBCDIC - Korean Extended
20838IBM EBCDIC - Thai
20866Russian - KOI8-R
20871IBM EBCDIC - Icelandic
20880IBM EBCDIC - Cyrillic (Russian)
20905IBM EBCDIC - Turkish
20924IBM EBCDIC - Latin-1/Open System (1047 + Euro symbol)
20932JIS X 0208-1990 & 0121-1990
20936Simplified Chinese (GB2312)
21025IBM EBCDIC - Cyrillic (Serbian, Bulgarian)
21027Extended Alpha Lowercase
21866Ukrainian (KOI8-U)
28591ISO 8859-1 Latin I
28592ISO 8859-2 Central Europe
28593ISO 8859-3 Latin 3
28594ISO 8859-4 Baltic
28595ISO 8859-5 Cyrillic
28596ISO 8859-6 Arabic
28597ISO 8859-7 Greek
28598ISO 8859-8 Hebrew
28599ISO 8859-9 Latin 5
28605ISO 8859-15 Latin 9
29001Europa 3
38598ISO 8859-8 Hebrew
50220ISO 2022 Japanese with no halfwidth Katakana
50221ISO 2022 Japanese with halfwidth Katakana
50222ISO 2022 Japanese JIS X 0201-1989
50225ISO 2022 Korean
50227ISO 2022 Simplified Chinese
50229ISO 2022 Traditional Chinese
50930Japanese (Katakana) Extended
50931US/Canada and Japanese
50933Korean Extended and Korean
50935Simplified Chinese Extended and Simplified Chinese
50936Simplified Chinese
50937US/Canada and Traditional Chinese
50939Japanese (Latin) Extended and Japanese
51932EUC - Japanese
51936EUC - Simplified Chinese
51949EUC - Korean
51950EUC - Traditional Chinese
52936HZ-GB2312 Simplified Chinese
54936Windows XP: GB18030 Simplified Chinese (4 Byte)
57002ISCII Devanagari
57003ISCII Bengali
57004ISCII Tamil
57005ISCII Telugu
57006ISCII Assamese
57007ISCII Oriya
57008ISCII Kannada
57009ISCII Malayalam
57010ISCII Gujarati
57011ISCII Punjabi
65000Unicode UTF-7
65001Unicode UTF-8
The following is a list of valid code page identifiers for Mac OS only:
IdentifierName
1ASCII
2NEXTSTEP
3JapaneseEUC
4UTF8
5ISOLatin1
6Symbol
7NonLossyASCII
8ShiftJIS
9ISOLatin2
10Unicode
11WindowsCP1251
12WindowsCP1252
13WindowsCP1253
14WindowsCP1254
15WindowsCP1250
21ISO2022JP
30MacOSRoman
10UTF16String
0x90000100UTF16BigEndian
0x94000100UTF16LittleEndian
0x8c000100UTF32String
0x98000100UTF32BigEndian
0x9c000100UTF32LittleEndian
65536Proprietary

LicenseInfo:   Information about the current license.

When queried, this setting will return a string containing information about the license this instance of a class is using. It will return the following information:

  • Product: The product the license is for.
  • Product Key: The key the license was generated from.
  • License Source: Where the license was found (e.g., RuntimeLicense, License File).
  • License Type: The type of license installed (e.g., Royalty Free, Single Server).
  • Last Valid Build: The last valid build number for which the license will work.
MaskSensitive:   Whether sensitive data is masked in log messages.

In certain circumstances it may be beneficial to mask sensitive data, like passwords, in log messages. Set this to to mask sensitive data. The default is .

This setting only works on these classes: AS3Receiver, AS3Sender, Atom, Client(3DS), FTP, FTPServer, IMAP, OFTPClient, SSHClient, SCP, Server(3DS), Sexec, SFTP, SFTPServer, SSHServer, TCPClient, TCPServer.

UseInternalSecurityAPI:   Tells the class whether or not to use the system security libraries or an internal implementation.

When set to , the class will use the system security libraries by default to perform cryptographic functions where applicable.

Setting this setting to tells the class to use the internal implementation instead of using the system security libraries.

This setting is set to by default on all platforms.

Trappable Errors (IPMonitor Module)

IPMonitor Errors

650   Cannot read packet.
1118   Invalid local host.

SSL Errors

270   Cannot load specified security library.
271   Cannot open certificate store.
272   Cannot find specified certificate.
273   Cannot acquire security credentials.
274   Cannot find certificate chain.
275   Cannot verify certificate chain.
276   Error during handshake.
280   Error verifying certificate.
281   Could not find client certificate.
282   Could not find server certificate.
283   Error encrypting data.
284   Error decrypting data.

TCP/IP Errors

10004   [10004] Interrupted system call.
10009   [10009] Bad file number.
10013   [10013] Access denied.
10014   [10014] Bad address.
10022   [10022] Invalid argument.
10024   [10024] Too many open files.
10035   [10035] Operation would block.
10036   [10036] Operation now in progress.
10037   [10037] Operation already in progress.
10038   [10038] Socket operation on non-socket.
10039   [10039] Destination address required.
10040   [10040] Message too long.
10041   [10041] Protocol wrong type for socket.
10042   [10042] Bad protocol option.
10043   [10043] Protocol not supported.
10044   [10044] Socket type not supported.
10045   [10045] Operation not supported on socket.
10046   [10046] Protocol family not supported.
10047   [10047] Address family not supported by protocol family.
10048   [10048] Address already in use.
10049   [10049] Can't assign requested address.
10050   [10050] Network is down.
10051   [10051] Network is unreachable.
10052   [10052] Net dropped connection or reset.
10053   [10053] Software caused connection abort.
10054   [10054] Connection reset by peer.
10055   [10055] No buffer space available.
10056   [10056] Socket is already connected.
10057   [10057] Socket is not connected.
10058   [10058] Can't send after socket shutdown.
10059   [10059] Too many references, can't splice.
10060   [10060] Connection timed out.
10061   [10061] Connection refused.
10062   [10062] Too many levels of symbolic links.
10063   [10063] File name too long.
10064   [10064] Host is down.
10065   [10065] No route to host.
10066   [10066] Directory not empty
10067   [10067] Too many processes.
10068   [10068] Too many users.
10069   [10069] Disc Quota Exceeded.
10070   [10070] Stale NFS file handle.
10071   [10071] Too many levels of remote in path.
10091   [10091] Network subsystem is unavailable.
10092   [10092] WINSOCK DLL Version out of range.
10093   [10093] Winsock not loaded yet.
11001   [11001] Host not found.
11002   [11002] Non-authoritative 'Host not found' (try again or check DNS setup).
11003   [11003] Non-recoverable errors: FORMERR, REFUSED, NOTIMP.
11004   [11004] Valid name, no data record (check DNS setup).