The Appliance Manager enables you to test network connectivity, using three commands: ping, traceroute, and tcpdump.
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Click Stop to terminate a test.
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If you log in to an appliance while a testing session is in progress, only the Abort button is accessible. Otherwise, that button is not visible.
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From the Maintenance menu, select ping/traceroute/tcpdump.
The Maintenance - ping/traceroute/tcpdump page appears. |
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From the Type field, click to select the test you want.
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If the IP / Hostname field is present, enter the IP address or hostname of the destination device. If the File Name field displays, its field is populated by a default name.
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In the Option field, enter the command option you want. For example, for ping, you could enter
-c 3 to stop after sending three ECHO_REQUEST packets. For available arguments, click Help. |
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To stop the test and see the complete results, click Stop. For example:
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Use the ping command to send Internet Control Message Protocol (ICMP) echo requests to a specified host.
By default, the ping command uses the mgmt0 interface. If you want to ping out of datapath interfaces, use the -I option with the local appliance IP address. For example:
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The following ping options are supported:
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Adaptive ping. Interpacket interval adapts to round-trip time, so that effectively not more than one (or more, if preload is set) unanswered probes present in the network. Minimal interval is 200 msec if not super-user. On networks with low rtt this mode is essentially equivalent to flood mode.
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count: Stop after sending count ECHO_REQUEST packets. With deadline option, ping waits for count ECHO_REPLY packets, until the time- out expires.
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flow label: Allocate and set 20 bit flow label on echo request packets. (Only ping6). If value is zero, kernel allocates random flow label.
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interval: Wait interval seconds between sending each packet. The default is to wait for one second between each packet normally, or not to wait in flood mode. Only super-user may set interval to values less 0.2 seconds.
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interface address: Set source address to specified interface address. Argument may be numeric IP address or name of device. When pinging IPv6 link-local address this option is required.
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preload: If preload is specified, ping sends that many packets not waiting for reply. Only the super-user may select preload more than 3.
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MTU discovery hint: Select Path MTU Discovery strategy. hint may be either do (prohibit fragmentation, even local one), want (do PMTU discovery, fragment locally when packet size is large), or dont (do not set DF flag).
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pattern: You may specify up to 16 “pad” bytes to fill out the packet you send. This is useful for diagnosing data-dependent problems in a network. For example, -p ff will cause the sent packet to be filled with all ones.
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tos: Set Quality of Service -related bits in ICMP datagrams. tos can be either decimal or hex number.
Traditionally (RFC1349), these have been interpreted as: 0 for reserved (currently being redefined as congestion control), 1-4 for Type of Service and 5-7 for Precedence. Possible settings for Type of Service are: minimal cost: 0x02, reliability: 0x04, throughput: 0x08, low delay: 0x10. Multiple TOS bits should not be set simultaneously. Possible settings for special Precedence range from priority (0x20) to net control (0xe0). You must be root (CAP_NET_ADMIN capability) to use Critical or higher precedence value. You cannot set bit 0x01 (reserved) unless ECN has been enabled in the kernel. In RFC2474, these fields has been redefined as 8-bit Differentiated Services (DS), consisting of: bits 0-1 of separate data (ECN will be used, here), and bits 2-7 of Differentiated Services Codepoint (DSCP). |
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Record route. Includes the RECORD_ROUTE option in the ECHO_REQUEST packet and displays the route buffer on returned packets. Note that the IP header is only large enough for nine such routes. Many hosts ignore or discard this option.
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Bypass the normal routing tables and send directly to a host on an attached interface. If the host is not on a directly attached network, an error is returned. This option can be used to ping a local host through an interface that has no route through it provided the option -I is also used.
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packetsize: Specifies the number of data bytes to be sent. The default is 56, which translates into 64 ICMP data bytes when combined with the 8 bytes of ICMP header data.
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sndbuf: Set socket sndbuf. If not specified, it is selected to buffer not more than one packet.
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timestamp option: Set special IP timestamp options. timestamp option may be either tsonly (only timestamps), tsandaddr (timestamps and addresses) or tsprespec host1 [host2 [host3 [host4]]] (timestamp prespecified hops).
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Print full user-to-user latency (the old behavior). Normally ping prints network round trip time, which can be different f.e. due to DNS failures.
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deadline: Specify a timeout, in seconds, before ping exits regardless of how many packets have been sent or received. In this case ping does not stop after count packet are sent, it waits either for deadline expire or until count probes are answered or for some error notification from network.
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Use the traceroute command to trace the route that packets take to a destination.
The following traceroute options are supported:
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Specify a network interface to obtain the source IP address for outgoing probe packets. This is normally only useful on a multi-homed host. (See the -s flag for another way to do this.)
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Set the max time-to-live (max number of hops) used in outgoing probe packets. The default is 30 hops (the same default used for TCP connections).
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Print hop addresses numerically rather than symbolically and numerically (saves a nameserver address-to-name lookup for each gateway found on the path).
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Set the base UDP port number used in probes (default is 33434). Traceroute hopes that nothing is listening on UDP ports base to base + nhops - 1 at the destination host (so an ICMP PORT_UNREACHABLE message will be returned to terminate the route tracing). If something is listening on a port in the default range, this option can be used to pick an unused port range.
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Bypass the normal routing tables and send directly to a host on an attached network. If the host is not on a directly-attached network, an error is returned. This option can be used to ping a local host through an interface that has no route through it (for example, after the interface was dropped by routed (8C)).
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Use the following IP address (which usually is given as an IP number, not a hostname) as the source address in outgoing probe packets. On multi-homed hosts (those with more than one IP address), this option can be used to force the source address to be something other than the IP address of the interface the probe packet is sent on. If the IP address is not one of this machine’s interface addresses, an error is returned and nothing is sent. (See the -i flag for another way to do this.)
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Set the type-of-service in probe packets to the following value (default zero). The value must be a decimal integer in the range 0 to 255. This option can be used to see if different types-of-service result in different paths. (If you are not running 4.4bsd, this may be academic since the normal network services like telnet and ftp don’t let you control the TOS). Not all values of TOS are legal or meaningful - see the IP spec for definitions. Useful values are probably â-t 16â (low delay) and â-t 8â (high throughput). If TOS value is changed by intermediate routers, (TOS=<value>!) will be printed once: value is the decimal value of the changed TOS byte.
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Toggle ip checksums. Normally, this prevents traceroute from calculating ip checksums. In some cases, the operating system can overwrite parts of the outgoing packet but not recalculate the checksum (so in some cases the default is to not calculate checksums and using -x causes them to be calculated). Note that checksums are usually required for the last hop when using ICMP ECHO probes (-I). So they are always calculated when using ICMP.
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Set the time (in milliseconds) to pause between probes (default 0). Some systems such as Solaris and routers such as Ciscos rate limit icmp messages. A good value to use with this is 500 (e.g. 1/2 second).
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Use the tcpdump command to display packets on a network.
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The following tcpdump options are supported:
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Before writing a raw packet to a savefile, check whether the file is currently larger than file_size and, if so, close the current savefile and open a new one. Savefiles after the first savefile will have the name specified with the -w flag, with a number after it, starting at 1 and continuing upward. The units of file_size are millions of bytes (1,000,000 bytes, not 1,048,576 bytes).
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Print the list of the network interfaces available on the system and on which tcpdump can capture packets. For each network interface, a number and an interface name, possibly followed by a text description of the interface, is printed. The interface name or the number can be supplied to the -i flag to specify an interface on which to capture.
This can be useful on systems that don’t have a command to list them (e.g., Windows systems, or UNIX systems lacking ifconfig -a); the number can be useful on Windows 2000 and later systems, where the interface name is a somewhat complex string. The -D flag will not be supported if tcpdump was built with an older version of libpcap that lacks the pcap_findalldevs() function. |
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Use spi@ipaddr algo:secret for decrypting IPsec ESP packets that are addressed to addr and contain Security Parameter Index value spi. This combination may be repeated with comma or newline separation.
Note that setting the secret for IPv4 ESP packets is supported at this time. Algorithms may be des-cbc, 3des-cbc, blowfish-cbc, rc3-cbc, cast128-cbc, or none. The default is des-cbc. The ability to decrypt packets is only present if tcpdump was compiled with cryptography enabled. secret is the ASCII text for ESP secret key. If preceded by 0x, then a hex value will be read. The option assumes RFC2406 ESP, not RFC1827 ESP. The option is only for debugging purposes, and the use of this option with a true ‘secret’ key is discouraged. By presenting IPsec secret key onto command line you make it visible to others, via ps(1) and other occasions. In addition to the above syntax, the syntax file name may be used to have tcpdump read the provided file in. The file is opened upon receiving the first ESP packet, so any special permissions that tcpdump may have been given should already have been given up. |
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Print ‘foreign’ IPv4 addresses numerically rather than symbolically (this option is intended to get around serious brain damage in Sun’s NIS server â usually it hangs forever translating non-local internet numbers).
The test for ‘foreign’ IPv4 addresses is done using the IPv4 address and netmask of the interface on which capture is being done. If that address or netmask are not available either because the interface on which capture is being done has no address or netmask or because the capture is being done on the Linux “any” interface, which can capture on more than one interface, this option will not work correctly. |
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Listen on interface. If unspecified, tcpdump searches the system interface list for the lowest numbered, configured up interface (excluding loopback). Ties are broken by choosing the earliest match.
On Linux systems with 2.2 or later kernels, an interface argument of “any” can be used to capture packets from all interfaces. Note that captures on the “any” device will not be done in promiscuous mode. If the -D flag is supported, an interface number as printed by that flag can be used as the interface argument. |
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Make stdout line buffered. Useful if you want to see the data while capturing it. For example,
tcpdump -l | tee dat or tcpdump -l > dat & tail -f dat |
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Load SMI MIB module definitions from file module. This option can be used several times to load several MIB modules into tcp-dump.
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Use secret as a shared secret for validating the digests found in TCP segments with the TCP-MD5 option (RFC 2385), if present.
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Don’t print domain name qualification of host names. For example, if you give this flag then tcpdump will print nic instead of nic.ddn.mil.
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Don’t put the interface into promiscuous mode. Note that the interface might be in promiscuous mode for some other reason; hence, -p cannot be used as an abbreviation for ‘ether host {local-hw-addr} or ether broadcast’.
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Assume ESP/AH packets to be based on old specification (RFC1825 to RFC1829). If specified, tcpdump will not print replay prevention field. Since there is no protocol version field in ESP/AH specification, tcpdump cannot deduce the version of ESP/AH protocol.
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Read packets from file (which was created with the -w option). Standard input is used if file is ‘’-’’.
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Snarf snaplen bytes of data from each packet rather than the default of 68 (with SunOS’s NIT, the minimum is actually 96). 68 bytes is adequate for IP, ICMP, TCP and UDP but may truncate protocol information from name server and NFS packets.Packets truncated because of a limited snapshot are indicated in the output with [|proto], where proto is the name of the protocol level at which the truncation has occurred.
Note that taking larger snapshots both increases the amount of time it takes to process packets and, effectively, decreases the amount of packet buffering. This may cause packets to be lost. You should limit snaplen to the smallest number that will capture the protocol information you’re interested in. Setting snaplen to 0 means use the required length to catch whole packets. |
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Force packets selected by “expression” to be interpreted the specified type. Currently known types are:
aodv Ad-hoc On-demand Distance Vector protocol cnfp Cisco NetFlow protocol rpc Remote Procedure Call rtp Real-Time Applications protocol rtcp Real-Time Applications control protocol snmp Simple Network Management Protocol tftp Trivial File Transfer Protocol vat Visual Audio Tool) wb distributed White Board |
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Make output saved via the -w option “packet-buffered”; that is, as each packet is saved, it will be written to the output file, rather than being written only when the output buffer fills.
The -U flag will not be supported if tcpdump was built with an older version of libpcap that lacks the pcap_dump_flush() function. |
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When parsing and printing, produce (slightly more) verbose output. For example, the time to live, identification, total length and options in an IP packet are printed. Also enables additional packet integrity checks such as verifying the IP and ICMP header checksum.
When writing to a file with the -w option, report, every 10 seconds, the number of packets captured. |
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Even more verbose output. For example, additional fields are printed from NFS reply packets, and SMB packets are fully decoded.
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Even more verbose output. For example, telnet SB... SE options are printed in full. With -X Telnet options are printed in hex as well.
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Write the raw packets to file rather than parsing and printing them out. They can later be printed with the -r option. Standard output is used if file is “-”.
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Used in conjunction with the -C option, this will limit the number of files created to the specified number, and begin overwriting files from the beginning, thus creating a ‘rotating’ buffer. In addition, it will name the files with enough leading 0s to support the maximum number of files, allowing them to sort correctly.
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Print each packet (minus its link level header) in hex. The smaller of the entire packet or snaplen bytes will be printed. Note that this is the entire link-layer packet, so for link layers that pad (e.g. Ethernet), the padding bytes will also be printed when the higher layer packet is shorter than the required padding.
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Drops privileges (if root) and changes user ID to user and the group ID to the primary group of user.
This behavior can also be enabled by default at compile time. |
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To access the tcpdump file, click on its name link. The Administration - Debug Files - Save File page appears.
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