| Digital UNIX | ||
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Digital UNIX Version 4.0 supports a variety of network administration software which is briefly described in the following sections.
Digital UNIX Version 4.0 supports the entire suite of networking commands from OSF Version 1.2, including: gated, finger, ftp, rdump, rdist, routed and the complete suite of remote commands, snmp, smtp, telnet, and tftp. The bootpd command has been folded into the Digital-specific joind command which provides configurations to clients using either the DHCP or BOOTP protocol. Additionally, Digital UNIX Version 4.0 supports the following Open Network Computing (ONC) Version 4.2 utility programs, which can be invoked by the inetd:
rwall/rwalld
rusers/rusersd
spray/rsprayd
rup/rstatd
rquotad
pcnfsd
The Ethernet packet filter is a software driver interface that provides demultiplexing of networking packet headers, as well as reception and transmission of packets containing user-defined network protocols. The packet filter can also function as an Ethernet monitor when used to filter specific network protocols.
Digital UNIX Version 4.0 supports the following packet filter applications:
/usr/sbin/rarpd − Reverse ARP daemon
The reverse ARP daemon responds to RARP requests on a network by sending an IP address to a host which only knows its Ethernet address. It uses the /etc/ethers file to map the Ethernet address to an IP address.
The reverse ARP daemon can serve IP addresses to remote PC clients. Also, some customers are using ULTRIX on DECstations today and rely on the Reverse ARP protocol to supply remote stations with their IP address. If they want to serve these addresses using a Digital UNIX Version 4.0 server, they can do so with the rarpd daemon.
/usr/sbin/tcpdump − TCP/IP tracing and monitoring tool
Digital UNIX Version 4.0 supports Version 2.2.1 of the tcpdump utility. This version of tcpdump uses the Berkeley Packet Filter (BPF) language.
The tcpdump utility is used to debug and analyze TCP/IP network activity, on both Ethernet and FDDI networks, and has some support for other protocol suites (including NFS). This product includes software developed by the University of California, Lawrence Berkeley Laboratory and its contributors.
/usr/sbin/tcpslice − Log file tool
The tcpslice utility manipulates tcpdump trace log files by either extracting pieces of or glueing together tcpdump log files. It can select portions of a large tcpdump log file and display selected traces without having to dump the entire log file.
/usr/sbin/nfswatch − NFS monitoring tool
Digital UNIX Version 4.0 supports Version 4.1 of nfswatch from Purdue University. The nfswatch utility is curses-based and displays the NFS traffic between any number of NFS servers and clients on a LAN.
/usr/sbin/nfslogsum − NFS log file summary tool
The nfslogsum utility condenses the log files produced by nfswatch into a traffic analysis summary and is very helpful in troubleshooting networks.
Note: Since the packet filter is an optional kernel subsystem, application programs that make calls to the packet filter kernel routines may fail if the packet filter is not configured in the currently running kernel. For more information, see the packetfilter(7) reference page.
Digital UNIX Version 4.0 supports the Dynamic Host Configuration Protocol (DHCP), a client/server framework in which the DHCP server can dynamically assign an IP address to a client as the client boots onto the network. Additionally, a DHCP server can provide configuration information to the client, such as the name of the BIND server or the name of the default router for that client.
For example, when a new system is booted for the first time, the DHCP server assigns that system a unique IP address; if that system is moved to another location on the same LAN (perhaps on a different subnet), the DHCP server ensures that a new IP address appropriate to that subnet is assigned to the system, if necessary, when it boots up for the first time.
As a result, with DHCP, customers with hundreds of clients no longer have to worry about the assignment of IP addresses; DHCP assigns IP addresses automatically and requires no intervention by a system administrator.
For more information on DHCP, see the Network Administration and the dhcp(7) reference page.
The bootpd daemon implements an Internet Boot Protocol server as defined in RFC 951, RFC 1532, and RFC 1533.
BOOTP is an extensible UDP/IP-based protocol that allows a booting host to configure itself dynamically without having to rely on user intervention. The BOOTP protocol assigns IP addresses to hosts, makes available a file containing a boot program that can be downloaded from a server, provides the address of that server, and if present the address of an Internet gateway.
Like DHCP, the BOOTP protocol supports the centralized management of network addresses.
The extensible SNMP agent in Digital UNIX Version 4.0 permits the dynamic addition of supported Management Information Bases (MIBs) on any Digital UNIX host. The MIB support that ships as part of the operating system allows management operations on the objects described in the following RFCs:
Internet MIB (RFc 1213)
FDDI MIB (RFC 1285)
Token Ring MIB (RFC 1231)
Host Resources MIB (RFC 1514)
Various routing MIBs as described in the section called The gated Daemon.
The extensible SNMP development tools are contained in the optional programming subset (PGMR).
The gated daemon allows any host with multiple network interfaces to function as an IP router by participating in various IP routing protocols (for example, RIP, OSPF, EGP, and BGP). Digital UNIX Version 4.0 supports the GateD Release 3.5 gated daemon from the Gatedaemon Project at Cornell University, which contains support for the following:
RIP Version 1 (RFC 1058)
Stipulates the proper subsuming of host routes, split horizon without poison reverse, and graceful shutdowns.
RIP Version 2 (RFC 1388)
Stipulates using IP Multicast where available; supports classless routing; uses next hop (if different).
OSFP Version 2 (RFC 1247)
Uses local-wire IP Multicast support, MIB support (RFC 1253), and reconfiguration.
Support for Routing Table MIB (RFC 1354)
EGP 2 (RFC 904)
A complete implementation of the specification, with optimizations for MILNET.
BGP Versions 2 and 3 (RFC 1163 and RFC 1267)
Complete implementations of specifications; BGP MIB (RFC 1269); AS path pattern matching RFC 1164); and OSPF/BGP Interaction (RFC 1403).
BGP Version 4 (RFC 1654)
DCN HELLO
Proper subsuming of host routes; split horizon without poison reverse.
Variable subnet masks through Routing Socket Support and improved synchronization of the kernel routing table
Routing Table Enhancements
Based on BSD 4.3 Reno radix tree, gated implements filtered routing based on policy. This allows network administrators to control the import and export of routing information by individual protocol, by source and destination autonomous system, source and destination interface, previous hop router, and specific destination address.
Network administrators can also specify a preference level for each combination of routing information being imported by using a flexible masking capability. Once the preference levels are assigned, gated decides which route to use independent of the protocols involved.
MIB Support for the Following Protocols ("Get Object" Support Only):
OSPF V2 MIB (RFC 1253)
EGP-MIB (RFC 1213)
BGP V3 MIB (RFC 1269)
For more information on gated, see the gated(8) and gated.conf(8) reference pages. Also, for a complete description of the gated.conf options, see the EGate Daemon Configuration Guide, which is accessible from the Digital UNIX Documentation Library page on the Digital UNIX Documentation CD-ROM.
The screend daemon is used in conjunction with the gateway screen facility to decide which IP packets should be forwarded when the system is acting as an IP gateway.
The gateway packet screening facility, on a Digital UNIX system acting as a gateway, allows the system manager to control which packets are forwarded or rejected. As a result, the gateway packet screening facility can be used as one part of a comprehensive network security policy. The facility consists of a kernel-resident mechanism and a user-level daemon, /usr/sbin/screend. When a packet is ready to be forwarded, the kernel mechanism submits the packet's headers to the daemon. The screend daemon then examines the headers and tells the kernel to forward or reject the packet, based on a set of rules defined in the configuration file, /etc/screend.conf. Optionally, some or all decisions can be logged allowing the network manager to detect improper configurations or potential security problems.
The UNIX-to-UNIX Copy Program (UUCP) program is actually a group of programs that supports communications between two computers running UNIX operating systems.
DEC OSF/1 supports the HoneyDanBer version of UUCP. The UUCP system enables batched, error-free file transfer and remote command execution between two UNIX systems. The UUCP system is most frequently used to transfer electronic mail, network news, and public domain software over low-speed, low-cost communications links.
A worldwide network that functions through the informal cooperation of the user community has grown up around UUCP. The UUCP network is a series of point-to-point links, with the majority of sites located in Europe and North America.
The UUCP protocol supports only direct connections between two systems. However, electronic news and mail delivery depend on third-party forwarding. To facilitate mail and news delivery, most connected sites are willing to relay files for other sites. The UUCP network depends on direct distance dialing networks and off-peak long distance rates for its continued functioning. For more information on UUCP, see uucp_setup(8).
Local Area Transport (LAT) is a Digital protocol that supports communications between host computer systems and terminal servers with terminals, PCs, printers, modems and other devices over local area networks (LANs). LAT software has the features required for a host to function as a service node, so requests for connections can be made by server users. The software also permits host applications to initiate connections to server ports, designated as application ports, to access remote devices. In Digital UNIX, the LAT driver is STREAMS-based and supports up to 4000 incoming connections, with a theoretical limit of 5000 users.
For more information on LAT, see the lat_intro(7) reference page and the System Administration guide.Note: In Digital UNIX, LAT supports both SVR4 and BSD-style tty devices. Integral serial tty devices and serial tty options share the same BSD tty namespace as LAT, which means that if users allocate special files for serial lines, those special files will reduce the number of BSD LAT devices that can be configured.
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