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HP TCP/IP Services for OpenVMS

HP TCP/IP Services for OpenVMS
Tuning and Troubleshooting


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Use quotation marks to preserve the case of this option.

-r

Reconfigures the specified subsystem. You must supply the subsystem name and the attribute list when you use this flag.

-s

Queries the subsystem state for the specified subsystems. If you omit the subsystem name, sysconfig displays the state of all the configured subsystems.

-u

Unconfigures and, if the subsystem is loadable, unloads the specified subsystem from the kernel.

Examples

The following examples show how to use the sysconfig command.
#1

TCPIP> sysconfig -s 
inet: loaded and configured 
net: loaded and configured 
socket: loaded and configured 
iptunnel: loaded and configured 
ipv6: loaded and configured 
snmpinfo: loaded and configured 
      

This example shows how to display the subsystems and their status.

#2

TCPIP> sysconfig -q net 
net: 
ifnet_debug = 0 
ifqmaxlen = 1024 
lo_devs = 1 
lo_def_ip_mtu = 4096 
nslip = 0 
      

This example shows how to display subsystem attributes and their values.

#3

TCPIP> sysconfig -s net 
net: loaded and configured 
      

This example shows how to query the state of a particular subsystem.


sysconfigdb

Manages the subsystem configuration database.


Format

sysconfigdb {-a | -u} [-t target] -f file subsystem-name

sysconfigdb {-m | -r} [-t target] -f file [subsystem-name]

sysconfigdb -d [-t target] subsystem-name

sysconfigdb -l [-t target] [subsystem-name,...]

description

The sysconfigdb utility is used to manage the subsystem configuration table (TCPIP$ETC:SYSCONFIGTAB.DAT). To specify another file as a target file, use the -t flag.

To modify a target file, create a stanza file. This stanza file contains the name of one or more subsystems, each with a list of attributes and their values, as described in Section 2.1.3.1.

Modifications that you make to the sysconfigtab are changed the next time the subsystem is reloaded.

When the target file is another file, there is no synchronization with the subsystem configuration database.

restrictions

You must have system management privileges to run the sysconfigdb utility to modify the system configuration table.

Parameters

subsystem-name

Specifies a subsystem that contains the attributes you want to modify. The subsystem name and attributes are in a stanza input file.

You must specify the subsystem name when deleting ( -d ), adding ( -a ), or replacing ( -u ) a subsystem.

In other cases, when you do not specify a subsystem name, the operation is attempted for all the subsystems and attributes specified in the input file.


Flags

-a

Adds the specified subsystem entry to the target file.

-d

Deletes the specified subsystem entry from the target file.

-f file

Specifies the input file, a stanza file that contains entries for one or more subsystems. The default target file is the SYSCONFIGTAB.DAT file. Specify another target file by using the -t target flag.

-l

Lists the specified subsystem entries in the target file. If you do not specify a subsystem name, all subsystem entries in the target file are listed. The SYSCONFIGTAB.DAT file is the default target file.

-m

Merges subsystem attributes specified in the input file with the subsystem attributes in the target file. If you do not specify a subsystem name, all subsystem entries in the input file are merged. The SYSCONFIGTAB.DAT file is the default target file.

-r

Removes the subsystem entries specified in the input file from the target file. The only entries removed are those that have attribute names and values that exactly match those in the input file. If you do not specify the subsystem name, all subsystem entries in the input file with attributes that match are removed from the target file. The SYSCONFIGTAB.DAT file is the default target database file.

-t file

Specifies the target file for the operation. If you do not specify this flag, the default target file is the SYSCONFIGTAB.DAT file.

-u

Replaces a subsystem entry in the target file with the subsystem entry specified in the input file.

Examples

The following examples show how use the sysconfigdb utility.
#1

$ TCPIP 
TCPIP> sysconfigdb -u -f table_mgr.stanza table_mgr_1 
      

This command replaces the table_mgr_1 entry in the SYSCONFIGTAB.DAT file with the information in the TABLE_MGR.STANZA file for the table_mgr_1 subsystem. The command updates the in-memory copy of the subsystem configuration database to match the modified SYSCONFIGTAB.DAT file.

#2

TCPIP> sysconfigdb -m -f table_mgr.stanza tbl_mgr_2 
      

This command merges the tbl_mgr_2 information from the table_mgr.stanza file with the information already in the tbl_mgr_2 entry in the SYSCONFIGTAB.DAT file. The command updates the in-memory copy of the subsystem configuration database to match the modified SYSCONFIGTAB.DAT file.

#3

TCPIP> sysconfigdb -l table_mgr_1 
table_mgr_1: 
              size = 10 
              name = Ten-Element-Table 
      

This command lists the entry for the subsystem table_mgr_1 . This command does not update the in-memory copy of the subsystem configuration database.

#4

TCPIP> sysconfigdb -d table_mgr_1 
      

This command deletes the table_mgr_1 entry from the SYSCONFIGTAB.DAT file and updates the in-memory copy of the subsystem configuration database to match the modified SYSCONFIGTAB.DAT file.


tcpdump

Provides dump analysis and packet capturing.


Format

tcpdump ["-B" | d | e | f | l | m | n | "-N" | "-O" | q | s | "-S" | t | v | x | "-X"]
[-b buffers]
[-c count]
[-F file]
[-r file]
[-s snaplen]
[-w file] expression

description

The tcpdump utility displays the headers and contents of packets on the network that match a boolean expression (filter). If no filter is supplied all packets processed by tcpdump will be displayed. The the packets that are processed can also be written to a binary file for later examination and filtering.

Parameters

expression

A boolean expression that provides a filter to select the packets to dump. If you do not specify the expression, all packets on the network are dumped. Otherwise, only packets that match the expression are dumped.

For information about specifying expressions, refer to Section 1.2.5.2.


Options

-b

Specifies the number of buffers used to communicate with the TCP/IP kernel. The default is 400 on Alpha systems and 50 on VAX systems.

"-B"

Displays buffer diagnostics showing when dropped packets occur. Use quotation marks to preserve the case of uppercase options.

-c

Exits after receiving count packets.

-d

Dumps the compiled packet-matching code to standard output and stops.

-e

Displays the link-level header on each dump line.

-f

Displays foreign internet addresses numerically rather than symbolically.

"-F" file

Uses file as input for the filter expression. Any additional expressions on the command line are ignored. Use quotation marks to preserve the case of uppercase options.

-l

Buffers the stdout line. This is useful if you want to see the data while capturing it.

-m

Enables multiline output from some protocols. This affects most ONC RPC decoding, as those protocols are often difficult to display on a single line.

-n

Does not convert addresses (for example, host addresses and port numbers) to names.

"-N"

Does not display domain name qualification of host names. For example, with this option, tcpdump displays nic instead of nic.ddn.mil . Use quotation marks to preserve the case of uppercase options.

"-O"

Does not run the packet-matching code optimizer. This is useful only if you suspect a bug in the optimizer. Use quotation marks to preserve the case of uppercase options.

-q

Quick (quiet) output. Displays less protocol information so output line are shorter.

-r file

Reads packets from file (which was created with the -w option). Standard input is used if a hyphen (-) is used to specify the file.

-s snaplen

Displays the number of bytes of data from each packet as specified by the value of snaplen, rather than the default of 68. The default of 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

Taking larger snapshots both increases the amount of time it takes to process packets and decreases the amount of packet buffering. This may cause packets to be lost. You should limit the value of snaplen to the smallest number that will capture the protocol information you need.

"-S"

Displays absolute, rather than relative, TCP sequence numbers. Use quotation marks to preserve the case of uppercase options.

-t

Does not display a timestamp on each dump line.

-tt

Displays an unformatted timestamp on each dump line.

-v

Displays verbose output. For example, the time to live and type of service information in an IP packet is displayed. If -m is also specified, ONC RPC packets sent using TCP are decoded twice: first as RPC, then as TCP. By default, the TCP decoding is suppressed.

-vv

Displays detailed verbose output. For example, additional fields are displayed from NFS reply packets.

-w file

Writes the raw packets to file rather than parsing and displaying them. They can later be displayed with the -r option. Standard output is used if a hyphen (-) is used to specify the file.

-x

Displays each packet (minus its link level header) in hexadecimal format.

The smaller of the entire packet or snaplen bytes is displayed.

"-X"

Displays packets in both hexadecimal and ASCII formats. Use quotation marks to preserve the case of uppercase options.

Examples

#1

$ tcpdump host sundown 
      

This example shows how to use the tcpdump utility to display all packets arriving at or departing from host sundown .

#2

$ tcpdump host sundown and ( hot or ace ) 
      

This example shows how to use the tcpdump utility to display traffic between sundown and either host hot or host ace .

#3

$ tcpdump ip host ace and not helios 
      

This example shows how to use the tcpdump utility to display all IP packets between ace and any host except helios .

#4

$ tcpdump net office 
      

This example shows how to use the tcpdump utility to display all traffic between local hosts and hosts on the network office .

#5

$ tcpdump gateway snup and (port 21 or 20) 
      

This example shows how to use the tcpdump utility to display all FTP traffic through Internet gateway snup .

#6

$ tcpdump ip and not net localnet 
      

This example shows how to use the tcpdump utility to display traffic neither sourced from nor destined for local hosts. If your network is connected to one other network by a gateway, this command does not produce any results on your local network.

#7

$ tcpdump tcp[13] & 3 != 0 and not src and dst net localnet      
      

This example shows how to use the tcpdump utility to display the start and end packets (the SYN and FIN packets) of each TCP conversation that involves a nonlocal host.

#8

$ tcpdump gateway snup and ip[2:2] > 576            
      

This example shows how to use the tcpdump utility to display IP packets longer than 576 bytes sent through gateway snup .

#9

$ tcpdump ether[0] & 1 = 0 and ip[16] >= 224      
      

This example shows how to use the tcpdump utility to display IP broadcast or multicast packets that were not sent using Ethernet broadcast or multicast.

#10

$ tcpdump icmp[0] != 8 and icmp[0] != 0 
      

This example shows how to use the tcpdump utility to display all ICMP packets that are not echo requests or replies (that is, not PING packets).

#11

$ tcpdump -s 1500 -envv ipv6 and udp port 521       
      

This example shows how to use the tcpdump utility to display all RIPv6 packets.

#12

$ tcpdump -s 1500 -envv ipv6 and ether host a:b:c:d:e:f       
      

This example shows how to use the tcpdump utility to display all IPv6 packets arriving at or departing from a host with the Ethernet address a:b:c:d:e:f .


TCPTRACE

Traces packets between two hosts.


Format

TCPTRACE host [/BUFFERS=n | /FULL | /OUTPUT=file | /PACKETS=n | /PORT=option | /PROTOCOL=option]

description

TCPTRACE traces packets as they travel between the local and remote host. You can trace all packets or you can use command qualifiers to monitor only those packets of interest.

Qualifiers

/BUFFERS=n

Optional. The default is 100.
Specifies the number of buffers that TCPTRACE allocates for temporary storage.
These buffers must be locked into the working set, so the number can be:

/FULL

Optional. The default is brief display.

Displays the packet's contents.

/OUTPUT=file

Optional. The default is screen display. Redirects the output from screen to the specified file. If this file name already exists, the output is appended to it.

/PACKETS=n

Optional. The default it 10.

Stops the trace after the specified number of packets is displayed.

/PORT={LOCAL=n | REMOTE=n}

Optional for port number. The default is that all traffic is displayed.

Required for port type. Filters the trace to the specified port.

/PROTOCOL={ARP | ICMP | IP | TCP | UDP}

Optional. The default is /PROTOCOL=IP.

Filters the specified protocol.


Examples

The following examples show how to use the TCPTRACE command.
#1

$ TCPTRACE HOST1 /FULL /PORT=(REMOTE=21) 
      

This example shows how to use the TCPTRACE command to trace packets between the local system and Host1 . TCPTRACE filters all packets except those packets directed to port 21 on the remote host.

#2

$ TCPTRACE HOST2 /PORT=(LOCAL=23, REMOTE=1056) - 
_$ /FULL /PACKETS=30 /OUTPUT=TELNET_TRACE.TXT 
      

This example shows how to use the TCPTRACE command to trace packets between the local system and Host2 . TCPTRACE filters all packets except those packets directed to port 23 on the local host and port 1056 on the remote host. The trace results are output to a file with the name TELNET_TRACE.TXT. The trace stops after 30 packets meeting the specifications are encountered.


traceroute

Displays the route that packets take to the network host.


Format

traceroute [-m max_ttl] [-n] [-p port] [-q nqueries] [-r] [-s src_addr] [-v] [-w waittime] host [packetsize]

description

The Internet is a large and complex aggregation of network hardware connected together by gateways. The traceroute command tracks the route that packets follow from gateway to gateway. The command uses the IP protocol time-to-live (TTL) field and attempts to elicit an ICMP TIME_EXCEEDED response from each gateway along the path to a particular host.

The only mandatory parameter is the destination host name or IP address. The default probe datagram length is 38 bytes, but you can increase this value by specifying a packet size (in bytes) after the destination host name. This is useful when the -f option is given for MTU discovery along the route. You should start with the maximum packet size for your own network interface (if the given value is even bigger, traceroute attempts to select a more appropriate value). If no packet size is given when using the -f option, traceroute determines the initial MTU automatically.

To track the route of an IP packet, traceroute launches UDP probe packets with a small TTL (time-to-live) and then listens for an ICMP "time exceeded" reply from a gateway. Probes start with a TTL of 1 and increment by one until either an ICMP "port unreachable" is returned (indicating that the packet reached the host) or until the maximum number of hops is exceeded (the default is 30 hops and can be changed with the -m option). At each TTL setting, three probes are launched (the number can be changed with the -q option), and traceroute displays a line showing the TTL, address of the gateway, and round-trip time of each probe. If the probe answers come from different gateways, traceroute displays the address of each responding system. If there is no response within a 3-second timeout interval (which can be changed with the -w option), traceroute displays an asterisk (*) for that probe.

To prevent the destination host from processing the UDP probe packets, the destination port is set to an unlikely value. If necessary, you can change the destination port valued with the -p option.

Note

This program is intended for use in network testing, measurement, and management. It should be used primarily for manual fault isolation. Because of the load it could impose on the network, do not use traceroute during normal operations or from automated scripts.

Flags

-A

Looks up the AS-number (autonomous system) for each hop's network address at the whois server specified by the -h option.

-a

If the destination host has multiple addresses, traceroute probes all addresses if this option is set. Normally, only the first address as returned by the resolver is attempted.

-c stoptime

Specifies a delay (in seconds) to pause between probe packets. This can be necessary if the final destination is a router that does not accept undeliverable packets in bursts.

-f

Disables IP fragmentation. If the given packet size is too big to be handled unfragmented by a machine along the route, a "fragmentation needed" status is returned, and the indicator !F is printed. If a gateway returns the proper MTU size to be used, traceroute automatically decreases the packet size to this new value. If the proper MTU size is not returned, traceroute chooses a smaller packet size.

-g gateway

Enables the IP LSRR (loose source record route) option. This is useful for asking how somebody at the specified gateway reaches a particular target.

-h server

Specifies the name or IP address of the whois server that is contacted for the AS-number lookup, if the -A option is given.

-i initial_ttl

Sets the starting time-to-live value to initial_ttl , to override the default value of 1. Effectively this skips processing for intermediate hosts that are less than initial_ttl hops away.

-k

Keeps the connection to the whois server permanently open. This speeds lookups considerably, because a connection setup for each individual lookup is not necessary. However, not all whois servers support this feature.

-l

Prints the value of the TTL field in each packet received. (This flag can be used to help detect asymmetric routing.)

-m max_ttl

Sets the maximum time-to-live (maximum number of hops) used in outgoing probe packets. The default is 30 hops, which is the same default used for TCP connections.

-N

Displays the network name for each hop. If a BIND resolver cannot be reached, network names are retrieved just from the /etc/networks file.

-n

Displays the hop IP addresses using dotted-decimal notation. This saves a name server address-to-name lookup for each gateway found on the path. It also prevents a reverse lookup for numeric dotted-quad addresses given on the command line, such as destination host or -g gateway addresses.

-p port

Sets the base UDP port number used in probes. (The default value is 33434.) The traceroute command presumes that nothing is listening on UDP ports base to base+nhops-1 at the destination host (so an ICMP "port unreachable" message is returned to terminate the route tracing). If another process is listening on a port in the default range, use this option to pick an unused port range.

-Q maxquit

Stops probing this hop after the number of consecutive timeouts specified by maxquit are detected. The default value is 5. Useful in combination with -S if you have specified a big nqueries probe count.

-q nqueries

Sets the number of probes launched at each TTL setting. The default is 3.

-r

Bypasses the normal routing tables and sends 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 or GATED).

-S

Prints a summary of per-hop minimum/average/maximum rtt (round-trip time) statistics. This flag suppresses the per-probe rtt and TTL reporting. To obtain more detailed statistics, increase the default nqueries probe count. For more information, see also the -Q option.

-s src_addr

Uses the following IP address (which must be given as an IP number, not as a host name) as the source address in outgoing probe packets. On hosts 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 on which the probe packet is sent. If the IP address is not one of this machine's interface addresses, an error is returned and nothing is sent.

-v

Lists any received ICMP packets other than TIME_EXCEEDED and UNREACHABLE.

-w waittime

Sets the time (in seconds) to wait for a response to a probe. The default is 3 seconds.

Parameters

host

Specifies the name or IP address of the destination host. This parameter is required.

packetsize

Specifies the default length for a probe datagram. This parameter is optional. The default is 38 bytes.

Examples

The following examples show how to use the traceroute command.
#1

localhost> traceroute nis.nsf.net 
 
traceroute to nis.nsf.net (35.1.1.48), 30 hops max, 56 byte packet 
 
 1  helios.ee.lbl.gov (128.3.112.1)  19 ms  19 ms  0 ms 
 2  lilac-dmc.Berkeley.EDU (128.32.216.1)  39 ms  39 ms 19 ms 
 3  lilac-dmc.Berkeley.EDU (128.32.216.1)  39 ms  39 ms 19 ms 
 4  ccngw-ner-cc.Berkeley.EDU (128.32.136.23)  39 ms  40 ms  39 ms 
 5  ccn-nerif22.Berkeley.EDU (128.32.168.22)  39 ms  39 ms  39 ms 
 6  128.32.197.4 (128.32.197.4)  40 ms  59 ms  59 ms 
 7  131.119.2.5 (131.119.2.5)  59 ms  59 ms  59 ms 
 8  129.140.70.13 (129.140.70.13)  99 ms  99 ms  80 ms 
 9  129.140.71.6 (129.140.71.6)  139 ms  239 ms  319 ms 
10  129.140.81.7 (129.140.81.7)  220 ms  199 ms  199 ms 
11  nic.merit.edu (35.1.1.48)  239 ms  239 ms  239 ms 
      


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