| Tg
|
Specifies a character tag. Some tags must be followed by an =
(equal sign) and a Value. Other tags appear in a Boolean form with no value. The recognized tags are:
| bf |
Specifies the boot file. The Value is an ASCII string that can be optionally surrounded by double quotes.
The client's request and the hd and bf tags determine how the server fills in the boot file field of the bootp reply packet.
- If the client's bootp request specifies an absolute path name and that file exists on the server machine, that path name is returned in the reply packet. If the file cannot be found, the request is discarded; no reply is sent.
- If the client's bootp request specifies a relative path name, a full path name is formed by adding the value of the hd tag and testing for existence of the file. If the hd tag is not supplied in the configuration file, or if the resulting boot file cannot be found, the request is discarded.
- If a client's bootp request specifies a null boot file, the server always replies with the boot file field filled according to the following guidelines:
- If the bf tag gives an absolute path name and the file exists, that path name is returned in the reply packet.
- If the hd and bf tags combined specify an accessible file, that file name is returned in the reply.
- If a complete file name cannot be determined or the file does not exist, the reply contains a zeroed-out boot file field.
In all cases, the existence of a file means that, in addition to actually being present, the file must have its Public Read Access bit set for the tftp program to permit the file transfer. Also, all file names are tried as FileName.HostName first. Then, the file names are tried simply as FileName, thus providing for individual per-host boot files. |
| bs |
Specifies the boot file size. The Value is in 512-octet blocks, which can be decimal, octal, or hexadecimal integers, or the keyword auto
, which causes the server to automatically calculate the boot file size at each request. Specifying the bs tag as a Boolean value is the same as specifying the keyword auto
for Value. |
| bt |
This tag is obolete and is ignored. |
| cs |
Cookie server address list. |
| ds |
Domain name server address list. |
| dt |
Specifies that an old style boot be performed to this client. This tag is needed to do a broadcast boot on some Xstations. |
| gw |
Specifies the gateway address list. If this tag is defined, the sm (subnet mask) tag must also be defined. |
| ha |
Specifies the host hardware address. The Value is in hexadecimal with optional periods and/or a leading 0x. The ha tag must be preceded, explicitly or implicitly, by the ht tag. |
| hd |
Specifies the boot file home directory. The Value is an ASCII string that can be optionally surrounded by double quotes. |
| hn |
Specifies that the host name should be sent to clients. The hn tag is a Boolean tag and does not take the =
(equals sign) and a Value. |
| ht |
Specifies the host network type. The Value is an unsigned decimal, octal, or hexadecimal integer, or a symbolic name. The ht tag must precede the ha tag, explicitly or implicitly.
The bootpd daemon supports the following network hardware types:
| Network Type |
Symbol(s) |
| 10Mb Ethernet |
ether or ethernet |
| IEEE 802.3 Ethernet |
ieee802 |
| IEEE 802.5 Token Ring |
tr or tokenring |
| FDDI |
fddi |
Since the 10Mb Ethernet and the IEEE 802.3 Ethernet use the same network adapter, the hardware address for both networks is the same. In cases like this, the client can have more than one entry in the /etc/bootptab file on a designated boot host. However, each entry must have a different hostname for the client and a different host network type. In this case, one entry would have a host network type of ether and the other entry would have a host network type of ieee802. This allows the client to boot over either the 10Mb Ethernet or the IEEE 802.3 Ethernet. |
| ip |
Specifies the client's IP address. The Value is a single IP address in standard Internet dot notation. The IP address can use decimal, octal, or hexadecimal numbers (octal numbers begin with 0, hexadecimal numbers begin with 0x or 0X). The ip tag, used as a Boolean value, looks up the IP address using the host name field. |
| lg |
MIT-LCS UDP log server address list. |
| lp |
Line Printer Server (LPR) server address list. |
| ns |
IEN-116 name server address list. |
| rl |
Resource location protocol server address list. |
| sa |
Specifies the IP address of the TFTP server where the client's boot file resides. The Value is a single IP address in standard Internet dot notation. The IP address can use decimal, octal, or hexadecimal numbers (octal numbers begin with 0, hexadecimal numbers begin with 0x or 0X). The default TFTP server is the client's bootpd server. |
| sm |
Specifies the host subnet mask. The Value is a single IP address in standard Internet dot notation. The IP address can use decimal, octal, or hexadecimal numbers (octal numbers begin with 0, hexadecimal numbers begin with 0x or 0X). |
| tc |
Specifies the table continuation, which points to a similar "template" host entry. The Value may be the host name or IP address of any host entry previously listed in the configuration file.
The tc tag is used to list commonly shared values for certain tags (such as name servers) in one host entry. Often, this template entry is a dummy host that does not actually exist and never sends the bootpd daemon requests. This tag may appear anywhere in the host entry.
Information explicitly specified for a host always overrides information implied by a tc tag, regardless of its location within the entry.
If it is necessary to delete a specific tag after it has been inferred through the tc tag, use the :tag@: construction to remove the effect of the tag feature. For example, to completely undo an IEN-116 name server specification, use :ns@: at an appropriate place in the configuration entry. If a tag has been deleted, it can be reset through the tc tag. |
| to |
Time zone offset of client's subnet in seconds from Coordinated Universal Time. |
| ts |
Time server address list. |
The following tags are specific to the Xstation product:
| T170 |
Specifies the port number used by the x_st_mgr daemon. The Value is specified in ASCII hexadecimal and must equal the port number assigned to the x_st_mgrd in the /etc/services file. If the x_st_mgr is on port 7000, the tag is T170 = 1B58. If the x_st_mgr is on port 9000, the tag is T170 = 2328. |
| T175 |
Specifies the host as a primary or a secondary boot server. If the Value is 00
, the host is a primary boot server for this Xstation. If the response Value is non-zero, then the host is a secondary server and will respond to a boot request for this client only after the delay time of Value seconds has elapsed.
In a network environment, it is desirable to have multiple hosts from which an Xstation can boot, so the Xstation can boot from an alternate server when the default host is not active. A problem can develop if a large number of Xstations continue to boot from one reliable alternate server when their default servers are back in operation. This problem is alleviated by requiring secondary servers to wait the specified number of seconds to give the primary server a chance to respond.
In addition, an Xstation will attempt to boot from the file server used for the previous boot. If the Xstation booted from the primary server, the server boots the Xstation immediately. If the Xstation booted from a secondary server, then the server will wait the specified delay time to give the primary server a chance to respond. |
| T176 |
Specifies the input device for the Xstation. If the value is 00
, the input device is the mouse. If the value is non-zero, the tablet is the input device, with value equal to the port number on the Xstation to which the tablet is connected (for example, 01
indicates that the tablet is connected to serial port 1 on the Xstation). |
| T177 |
Specifies how an Xstation 130 uses a fixed disk, if a fixed disk is present. The optional fixed disk for the Xstation 130 contains storage for a Pixmap/Font cache file and all the files needed for boot and terminal operation, if the user so specifies. When an Xstation uses the bootp program, the bootp response contains the value of the T177 tag field.
To use the fixed-disk functions, enter a 16-bit hexadecimal tag field in the /etc/bootptab file entry for the Xstation 130, using the identifier T177.
The tag field bits are defined as follows:
| Bit 0 |
reserved. |
| Bit 1 |
reserved. |
| Bits 2-4 |
These bits indicate how to use the fixed disk for files that are not font-related. The bit values are defined as follows:
| 0x00 |
Use the network file server for the boot file. Do not access the fixed disk. |
| 0x01 |
Use the fixed disk for the boot file. Do not access the network file server. |
| 0x02 |
Use the fixed disk for the boot file, but use the network file server as backup if the fixed disk cannot satisfy the request. |
| 0x03 |
Use the network file server for the boot file, but use the fixed disk as backup if the network file server cannot satisfy the request. |
| 0x04 |
Use the fixed disk for the boot file and if the file does not exist on the fixed disk, read the file from the network file server and store it on the fixed disk. |
| 0x05 |
Use the network file server for the boot file and write the boot file to the fixed disk. This updates the boot file on the fixed disk. |
|
|
| Bits 5-7 |
These bits indicate how to use the fixed disk for font files. The bit values are defined as follows.
| 0x00 |
Use the network file server for all files. Do not access the fixed disk. |
| 0x01 |
Use the fixed disk for all files. Do not access the network file server. |
| 0x02 |
Use the fixed disk for all files but use the network file server as back up if the fixed disk cannot satisfy the request. |
| 0x03 |
Use the network file server for all files but use the fixed disk as back up if the network file server cannot satisfy the request. |
| 0x04 |
Use the fixed disk for all files, and if a file does not exist on the fixed disk, read the file from the network file server and store it on the fixed disk. |
| 0x05 |
Use the fixed disk for all files. However, if the network file server has a more recent version of the file, then read the file from the server, store it on the fixed disk, and use the new file. |
|
| Bit 8 |
Page pixmaps to fixed disk. If set, pixmaps are paged to the fixed-disk page file. If clear, the network file server manages the page file. |
| Bits 9-16 |
reserved. |
Example: T177 = 0190
uses the fixed disk for the boot file, and all other files, and page pixmaps to the fixed disk. |