PING conch.pencom.com: 100 byte packets 100 bytes from 198.3.200.86: icmp_seq=0. time=3. ms 100 bytes from 198.3.200.86: icmp_seq=1. time=4. ms 100 bytes from 198.3.200.86: icmp_seq=2. time=3. ms 100 bytes from 198.3.200.86: icmp_seq=3. time=5. ms 100 bytes from 198.3.200.86: icmp_seq=4. time=4. ms 100 bytes from 198.3.200.86: icmp_seq=5. time=8. ms 100 bytes from 198.3.200.86: icmp_seq=6. time=3. ms 100 bytes from 198.3.200.86: icmp_seq=7. time=3. ms 100 bytes from 198.3.200.86: icmp_seq=8. time=3. ms 100 bytes from 198.3.200.86: icmp_seq=9. time=3. ms conch.pencom.com PING Statistics 10 packets transmitted, 10 packets received, 0% packet loss round-trip (ms) min/avg/max = 3/3/8 $ /etc/ping brat 100 10 PING brat.pencom.com: 100 byte packets brat.pencom.com PING Statistics 10 packets transmitted, 0 packets received, 100% packet loss $ In the first example, the 100 says to use 100 bytes of data in each message and the 10 says to use 10 messages. All 10 message were returned. The second example shows what happens when you attempt to ping a host that is not up. Once you determine that the remote host is not responding, you can either attempt to get the machine back up or wait until later to use it. If the machine is on your LAN, it should be fairly easy to go to it and start it running or talk to a local administrator. If the machine is somewhere remote, you may need to phone or e-mail someone to get assistance. If the machine is a resource on the Internet that is offered by some other school or company, you should probably just wait until it is running again unless your need is urgent (for both you and the remote administrator). Summary In this chapter, you have learned how UNIX machines are networked and how to take advantage of that networking. You have learned to log in to remote machines, copy files, begin to surf the Internet, and troubleshoot minor problems. By using these network services, you will be able to perform useful work on networked systems and explore the "information superhighway." ©Copyright, Macmillan Computer Publishing. All rights reserved. UNIX Unleashed, System Administrator's Edition - 7 - Communicating with Others by Ron Dippold and Fred Trimble From its inception, the purpose of the Internet has been to facilitate communication among people. It was originally developed by the military to provide a vast distributed communications network capable of continued operation in case of a nuclear attack. Its designers wanted a distributed network to eliminate the possibility of a "vulnerable central node." They also wanted a communications protocol that would be independent of any particular physical media. Despite its military roots, it has become characterized by the general public as the "Infobahn," "Information Superhighway," and "Cyberspace." Today, some twenty years later, the benefits of the Internet are being realized by many groups of people, including secondary schools, home users, and private industry. The Internet infrastructure was originally designed to support applications such as electronic mail and file transfer. Although electronic mail is still the most popular application on the Internet, other networking hardware and protocols continue to evolve so that they can support other types of communication, including real-time audio and video. Throughout the history of the Internet, UNIX has certainly played a major role. Most early UNIX systems provided built-in support for the Internet's main protocol: TCP/IP (Transmission Control Protocol). Therefore, this chapter covers the following topics, with an emphasis on UNIX facilities where appropriate: E-mail Electronic mail allows you to exchange messages with other people all over the world. Many electronic mail programs have extended features, such as the ability to attach binary files. USENET USENET is the world's largest electronic discussion forum. One of the most popular features of the Internet, it allows people all over the world to discuss topics and exchange ideas on a wide variety of subjects. Talk The talk command allows two people to exchange text messages in real-time. IRC Internet Relay Chat extends the capabilities of the "talk" command. It provides a real-time multiple person discussion forum, much like a CB radio channel. Multimedia The Internet allows real-time audio and video to be transmitted. The Future This section provides a glimpse into the future of the Internet. Electronic Mail (E-Mail) Electronic mail is the most widely used application on the Internet. It is known as an asynchronous type of communication system, because after a mail message has been sent, it resides on the recipient's computer until the recipient logs on and retrieves the message. This section focuses on many facets of e-mail, including the structure of a mail message, sending binary data (such as a graphics file) with a mail message, e-mail addressing, how messages are sent over the Internet, and common end-user mail programs. Components of a Mail Message A mail message consists of two main sections: a message header and a message body. The header contains information such as who sent the message and when it was sent. The body contains the actual message text. Some people finish their messages with an optional third part known as a "signature." Each of these mail message sections is described in detail in the following sections. Message Headers The message header consists of several lines at the top, formatted as "keyword: value" pairs. Messages sent to a user who is located on the same local UNIX host using the mail or mailx program have a very simple structure. For example: From smithj Thu Apr 24 00:42 EDT 1997 To: jonest Subject: Code Review Meeting Status: R Please plan on attending the code review meeting tomorrow at 10:00am. The message header of a mail message that ends up going over the Internet, however, is much more complex. For example: From nihil@eniac.seas.void.edu Thu Apr 24 08:15:01 1997 Flags: 000000000015 Received: from phones.com (phones.com [229.46.62.22]) by happy.phones.com (8.6.5/QC-BSD-2.1) via ESMTP; id IAA13973 Thu, 24 Apr 1997 08:14:59 -0800 for <rdippold@happy.phones.com> Received: from linc.cis.void.edu (root@LINC.CIS.VOID.EDU [230.91.6.8]) by phones.com (8.6.5/QC-main-2.3) via ESMTP; id IAA14773 Thu, 24 Apr 1997 08:14:56 -0800 for <rdippold@phones.com> Received: from eniac.seas.void.edu (nihil@ENIAC.SEAS.VOID.EDU [230.91.4.1]) by linc.cis.void.edu (8.6.5/VOID 1.4) with ESMTP id LAA17163 for <rdippold@phones.com> Thu, 24 Apr 1997 11:14:45 -0500 Received: from localhost by eniac.seas.void.edu id LAA24236; Thu, 24 Apr 1997 11:14:44 -0500 From: nihil@eniac.seas.void.edu [B Johnson] Sender: nihil@ocean.void.edu Reply-To: nihil@void.edu,nihil@freenet.com Cc: group-stuff@uunet.UU.NET Cc: james@foobar.com Message-Id: <199302011614.LAA24236@eniac.seas.void.edu> Subject: Re: Apple IIe/IIgs Software and books for SALE To: rdippold@phones.com (Ron Dippold) Date: Thu, 24 Apr 97 11:14:44 EST In-Reply-To: <CMM.342342.rdippold@happy.phones.com>; from "Ron Dippold" at Apr 24, 97 1:00 am X-Mailer: ELM [version 2.3 PL11-void1.13] Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Length: 10234 Message headers are constructed for you automatically by mail software known as "mail user agents" (MUA) and "mail transport agents" (MTA). In fact, the presence of certain items in the header, such as carbon copies and receipt notification, depend on the sophistication of the mail software itself. These components of an electronic mail system are discussed in detail in a later section. Some header information is intuitive. Other sections require some explanation. Here's the first line from the previous example: From nihil@eniac.seas.void.edu Thu Apr 24 08:15:01 1997 This line was added by the MTA on the local system (sendmail). It is used as a quick message summary, noting who sent the message and when. Because many mail systems store all of a user's mail messages in a single text file, such summary lines are also used to separate messages within the file. This provides a way to tell the end of one message from the start of the next. For most mail programs, this is the text From at the start of a line. This also means that if you try to place a From at the start of a line of text in your actual message, your mail program should place a > or some other character before it, so that it doesn't falsely indicate the start of a new message. Flags: 000000000015 The Flags field, which is specific to Berkeley mail and mailx, was also added by the local mail program. Each message can have several different statuses, such as deleted, unread, and flagged for further attention. This varies with the sophistication of the mail program. Received: from phones.com (phones.com [229.46.62.22]) by happy.phones.com (8.6.5/QC-BSD-2.1) via ESMTP; id IAA13973 Thu, 24 Apr 1997 08:14:59 -0800 for <rdippold@happy.phones.com> Each system that receives mail adds its own received header on top of the message. Because this is the first such header in the message, it must indicate the last mail transfer. The machine happy.phones.com (where my mail is located) received the message from phones.com (our company gateway) on April 24, 1997. The transfer was done using sendmail 8.6.5 (although you can't tell from this header that it was sendmail) and the protocol used was ESMTP. The intended recipient is listed last. This can change as the message goes through gateways, so it's helpful for tracking mail problems. Received: from linc.cis.void.edu (root@LINC.CIS.VOID.EDU [230.91.6.8]) by phones.com (8.6.5/QC-main-2.3) via ESMTP; id IAA14773 Thu, 24 Apr 1997 08:14:56 -0800 for <rdippold@phones.com> Here's the mail transfer that got the message from void.edu to my site. It's a direct connection with no intermediate hops. Received: from eniac.seas.void.edu (nihil@ENIAC.SEAS.VOID.EDU [230.91.4.1]) by linc.cis.void.edu (8.6.5/VOID 1.4) with ESMTP id LAA17163 for <rdippold@phones.com> Thu, 24 Apr 1997 11:14:45 -0500 Here, the mail system (linc.cis) at void.edu received the mail from another system at void.edu (eniac.seas). Received: from localhost by eniac.seas.void.edu id LAA24236; Thu, 24 Apr 1997 11:14:44 -0500 Finally, here's the original sending of the message. One interesting piece of information that can be gleaned from this whole exchange is the amount of time that it took to transfer the message. The message was sent at 11:14:44 -0500 and was received at 08:14:59 -0800 on the same day. The -0500 and -0800 show the time zone differences. To get equivalent times for both messages, you add 5 hours to the time of the sending and 8 hours to the time of receipt, to get 16:14:44 and 16:14:59, respectively. The message arrived in 15 seconds! From: nihil@eniac.seas.void.edu [B Johnson] This is the sender of the message. The portion in parentheses is a comment. It usually contains the person's name. Sender: nihil@ocean.void.edu Sender is the authenticated identity of the person who sent the message. This is where the sending computer tells you, as nearly as it can determine, the account that actually sent the message, regardless of what the From header says. This is useful if one person, such as a secretary, is authorized to send mail for another or if one member of a group is sending a message on behalf of the whole group. If the Sender header is the same as the From header, it doesn't need to be added. In this case, Nihil sent mail from a machine within his organization different from the one given in his address. If the From and Sender headers are radically different, however, the mail could be a forgery. Reply-To: nihil@void.edu,nihil@freenet.com The Reply-To header specifies who your reply should go to if you respond. Most mail software is smart enough to do this automatically. There are usually two reasons for using a Reply-To header. The first is if the address given in the From header is broken and you can't fix it. The second is if the specified primary address is somewhat unreliable. Nihil has another mail account at freenet.com if for some reason void.edu goes offline, he can still get much of his mail at his freenet account. Cc: group-stuff@zznet.ZZ.NET Cc: james@foobar.com The message was also sent to group-stuff@zznet.ZZ.NET and james@foobar.com. You can choose whether to include them in your reply. This also could have been done in a single header statement: Cc: group-stuff@zznet.ZZ.NET,james@foobar.com Either form is acceptable. Headers such as From or Sender, however, should appear only once in the entire header. Message-Id: <199302011614.LAA24236@eniac.seas.void.edu> Message identification is very helpful when trying to track a message for debugging purposes. It can also be used for message cancellation on USENET. The method of generating this unique ID varies from site to site. There should never be another message with this specific ID generated by any machine anywhere on the network. Subject: Re: Apple IIe/IIgs Software and books for SALE This is the subject of the message. My mail program shows me a one-line summary of each message, including the From, Date, and Subject headers. To: rdippold@phones.com (Ron Dippold) This is who the message was sent to. Sometimes your local computer will strip off the domain (@phones.com). Date: Thu, 24 Apr 97 11:14:44 EST This is the date the mail was originally sent. EST is Eastern Standard Time. In-Reply-To: <CMM.342342.rdippold@happy.phones.com>; from "Ron Dippold" at Apr 24, 97 1:00 am This message is a reply to a message that Ron sent with the message ID given above. X-Mailer: ELM [version 2.3 PL11-void1.13] The sender used the Elm Mail System to send this piece of mail. This information can also be useful in debugging. Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit MIME message format is discussed later in the chapter. Briefly, this says that the message contains only 7-bit text. Content-Length: 10234 The length of the body of the message (not shown here) is 10,234 characters. There are some other header items that might be occasionally useful for you to know: Bcc: recipient Bcc is blind carbon copy. This is like the Cc header, except that those recipients listed in the To and Cc headers don't see that the message was sent to those specified in the Bcc header. Use this to send a copy of a message to someone without letting the others know you're sending it. Encrypted: software keyhelp This indicates that the message body is encrypted with encryption software, and the keyhelp option helps with selecting the key used to decode. Note that the header itself cannot be encrypted because it contains vital routing information. Dates used in headers look like this: Thu, 24 Apr 97 11:44 -500 The day of week (Thu) is optional. The time is given in 24-hour format (00:00 23:59) local time. The last field is the time zone in one of several formats. UT or GMT Universal/Greenwich Mean Time EST or EDT Eastern time zone CST or CDT Central time zone MST or MDT Mountain time zone PST or PDT Pacific time zone -HHMM HH hours and MM minutes earlier than UT +HHMM HH hours and MM minutes later than UT RFC 822, which documents the standard format for Internet text messages, contains information about the header format. NOTE: Throughout this chapter, reference will be made to RFCs. RFC stands for Request For Comments and is the means by which the research and development community has documented the standards that form the basis of the Internet. For example, RFC 821 documents the SMTP protocol for sending mail. The Message Body The message body is separated from the message header by a single blank line. The message body contains the actual text of the message. Here, you are free to type whatever you want to the recipient. However, there are a few recommended guidelines to follow. Many mail systems can only handle lines of up to 65 characters. It is usually a good idea to keep the number of characters on a line less than that amount. Also, try to use a good mix of upper and lower case characters. IF YOU USE ALL UPPER CASE CHARACTERS, IT LOOKS LIKE YOU'RE SHOUTING! In addition to text, the message body sometimes contains a special character sequence known as an emoticon, such as :-). If you view this emoticon sideways, it looks like a smiley face. NOTE: When conversing with others, our body language, facial expressions, and tone of voice provide a framework for how our words are understood. Because this is not possible in an e-mail message, special character sequences called emoticons are used to embellish the text to connote emotion. Here is a list of some emoticons you might see, along with their usual meaning: :-) humor, laughter, friendliness :-( sadness, anger, upset :-O shocked :-$ put your money where your mouth is :-y said with a smile :-T keeping a straight face :-| no expression (:-D has a big mouth It is considered good practice not to overuse these symbols. Signatures Some e-mail messages conclude with an optional signature. A signature is a brief description of who sent the message, such as full name, telephone and fax numbers, and e-mail address. Some signatures try to embellish this information with a picture drawn with ASCII characters. It is considered good practice to limit your signature to five lines or less. Most modern mail programs can be configured to automatically append your signature to the end of your message. Sending Binary Data The protocol for sending e-mail over the Internet (SMTP) allows only for the transmission of ASCII text characters. Therefore, binary files, such as audio or video files, are not directly supported. The preferred method for sending binary data is to use a mail program that supports Multi-purpose Internet Mail Extensions (MIME). This is discussed in a later section. Before the advent of MIME, a technique used to circumvent this restriction is to encode such data as ASCII text before sending it with a mailer program, such as elm or mailx. On UNIX systems, use the uuencode program to convert a binary file to ASCII text. On the receiving end, the uudecode program to convert the data back to binary. For example, the following command can be used to mail a graphics file to a remote user: uuencode picture.tif picture.tif | mailx -s "image file" gcobb@netx.com The first argument to uuencode is the image file that will be encoded. The second argument is the name of the file that will be created on the remote user's system when the recipient runs the uudecode program. Since uuencode writes directly to standard output, it is piped to the mailx program. The mailx program will send a message to the remote user with a subject line of image file. NOTE: The uuencoded file will be about 35 percent larger than the original file. About 33 percent of that comes from converting 8-bit bytes to 6-bit bytes; the other 2 percent comes from control information in the encoding. On the remote system, the mail recipient first saves the message to a file, for instance, mail.save. The following command converts the ASCII characters back into binary format: uudecode mail.save In addition to the encrypted binary data, the file contains the mail header information put there by the mailx program. It is also possible that the sender added a commentary before the encrypted data. Upon examination of the encrypted file, there should appear a mail header and any commentary added by the sender. The encrypted data begins directly after the line containing the word begin, followed by UNIX file permissions and a filename. After the section with the encrypted data the word end appears on a line by itself. This information is used by the uudecode program for creating the file. In the preceding example, the following line appeared directly after the mail header: begin 777 picture.tif Therefore, after the uudecode program is run against the mail.save file, a file named picture.tif with file permissions 777 is created. Using the begin and end keywords, the uudecode program is usually able to distinguish between the mail text and the encrypted data. If uudecode cannot handle the file properly, you can edit the file and remove all text before the begin keyword and after the end keyword. The uudecode program should then work as expected. TIP: The technique specified above works okay for relatively small files, but what if you want to send someone a 10 megabyte file? Add 35 percent more for encryption overhead, and you have a hefty message by any estimation. Although you usually won't run into the problem with normal messages, a few sites running really old MTAs have a limit on message size, usually around 64,000 bytes. If you send your file as one big chunk, only a fourth of it may get there. What you need to do is split it into smaller chunks. You can do this manually, but there's a nice UNIX utility that will do the job for you: split. Just tell split the number of lines you want in each piece, and it creates a file containing the specified number of lines. The number of lines doesn't tell you the size of each file exactly, but you can experiment. We find that using 800 lines per piece on average provides a nice, safe 50,000-byte chunks. Here's how it works: uuencode bigfile bigfile > bigfile.uue split -800 bigfile.uue splits mail -s "Bigfile.uue 1 of 3" mybuddy < splitsaa mail -s "Bigfile.uue 2 of 3" mybuddy < splitsab mail -s "Bigfile.uue 3 of 3" mybuddy < splitsac rm bigfile.uue splits?? The split command takes as arguments the number of lines and the file to split, as well as a base name for the output files. In the above example, splits was used as the base name. It then names the resulting files splitsaa, splitsab, splitsac, and if necessary, all the way up to splitszz. This gives you 676 pieces. If that's not enough, you should probably use another method to transfer the file. The subjects with 1 of 3, 2 of 3, and 3 of 3 are just to let the receiver know the total number of pieces, and their proper sequence. Now the receiver has to save all the messages into a big file, edit out everything except the uuencoded stuff, and run uudecode on the resulting file. It is a cumbersome process, but it works. If you do this type of transfer, consider writing a UNIX shell script to automate the uuencode splitting, mailing, and recombining of the files. If you're on a UNIX system, uuencode, uudecode, and split should be standard. If you're using DOS or a Mac, you can obtain a copy via anonymous ftp. If you're using DOS, point your Web browser to http://oak.oakland.edu/pub/simtelnet/msdos/decode From here, download the file uuexe655.zip. This is a very nice uuencode and uudecode for the PC that is actually superior to the standard UNIX version. For instance, it automatically reorders the pieces of the file if they're out of order. If you're using a Mac, point your Web browser to http://tucows.idirect.com/mac/comp.html and download the file for UULite version 3.0. It's a very full-featured uuencoder for the Mac. For any computer for which you have a C compiler available, you can get the source code for uuencode.c and uudecode.c by pointing your Web browser to http://oak.oakland.edu/pub/misc/unix. This is the portable C source for the standard uuencode and uudecode and should work on almost any computer. The portable C versions of uuencode and uudecode are simple but are always there. Mail programs such as mailx are also discussed in more detail later in the chapter. Addressing Remote Systems To send a message over the Internet, you need to specify a specially formatted Internet address. It is composed of two major sections separated by an @ sign. The part of the address to the left of the @ sign is the Internet account that will receive the mail message. This is usually the login name of the mail recipient. The part of the address to the right of the @ sign is known as the domain name. It uniquely identifies a host on the Internet. All domain names on the Internet comprise the Domain Name System, which is a hierarchy that divides the Internet into logical groups (domains). The domain is read from right to left and specifies a series of progressively smaller logical domain names. Each part of the domain name is separated with a period. For example, note the following Internet address: ccarter@minn.com The rightmost portion of the domain, .com, indicates that this is a commercial site. The following list shows the most popular domains for the United States: com commercial edu education gov government mil military net network org organization Outside of the United States, sites can be registered to .com, .net, and .org. In addition, the two-letter ISO country code can also be used. For example, "ca" for Canada, "uk" for the United Kingdom, and so on. To the left of the highest level domain name (edu, org, and so on) can appear any number of logical subdomains. These are used to specify, in greater detail, the name of the host where the mail recipient can be found. By Internet convention, capitalization in the domain name is ignored. Therefore, the following Internet addresses are equivalent: ccarter@Minn.com, ccarter@MINN.com, and ccarter@MINN.COM). Most modern mail software ignores case in the username portion of the address for consistency. However, this is not a requirement. Therefore, it is considered good practice to preserve case for the username, just in case the recipient's system is using older mail software. An older type of addressing scheme is known as a UUCP bang-path address (bang is computer jargon for an exclamation point). It is unlikely that you will see an address in this format, though, and is mentioned here for historical reasons. In this type of scheme, you must indicate each system you want the mail to pass through. For example, note the following address for user katherine: comp01!comp02!comp03!katherine This indicates that you want the mail to pass through systems named comp01, comp02, and comp03. Once the message has been delivered to comp03, it will be delivered to katherine. How Messages Are Routed Over the Internet Before an Internet address in username@domain format can be used for transmission, it must be converted into an IP address. An IP address consists of four numbers, separated by dots, which uniquely identify a host on the Internet. For example, "128.254.17.7" is an example of an IP address. Translating an Internet address to an IP address is the province of systems on the Internet known as name servers. When a mail message is sent over the Internet, it is sent as a stream of packets, each containing a portion of the message. Each packet also contains the IP address of the destination. The packets are sent over the Internet using the IP protocol. Specialized networking systems on the Internet, known as routers, examine the IP address in each packet, and route it to the appropriate host. Many factors, such as network traffic volume, on various Internet backbones are taken into consideration in order to determine the best possible path. In fact, packets from the same mail message may take different routes. All packets are combined in the correct order on the receiving host using the TCP protocol. Sending Mail to Other Networks In addition to sending e-mail over the Internet, it is possible to send mail to other networks, such as online services. Internet E-Mail Gateways In theory, the Internet is a competitor with all the existing services such as AT&T Mail, CompuServe, and the rest. In practice, it's a neutral competitor. It's not some guided, malevolent entity that is trying to do away with any of the other services. Rather, it competes just by its existence; it offers more information and more connectivity than most of the services can ever hope to offer. Smart information services finally realized that this could be put to their advantage. Anyone who cares to can join the Internet, and a service that joins the Internet has advantages over its competitors. One huge advantage is connectivity. As soon as a mail service adds a computer (known as a gateway) that can transfer from its system to the Internet and vice versa, its users can exchange mail with anyone on the service or with anyone on the Internet. That's a lot of people. So many services are now offering some sort of mail gateway. Even Prodigy, which was somewhat late to grasp the possibilities, has one now. Instead of GEnie needing to install a special gateway to talk to Prodigy, and one to CompuServe, and one to SprintMail, and one to BubbaNet, it can set up and maintain just one gateway to the Internet, through which everything flows. Given the glacial speed with which most of the online services implement upgrades like this, requiring only a single gateway is a good thing. So now anyone can send e-mail anywhere! Well, not exactly. Addressing Issues It turns out that the services that connect to the Internet keep their same old account names and horrible mail systems. CompuServe's octal account addresses are as much an anachronism as punch cards, but because of the company's current investment, it isn't going to change them. And you can't just send a mail message to a CompuServe account using an Internet-style address. A CompuServe ID looks something like this: 112233,44 In Internet addressing, a comma separates members of a list so you can't use the comma in the Compuserve address. There's a way around that (use a period instead of a comma) but you have to know that in advance. Someone trying to send mail to a system has to deal with those quirks. Hence this section, which details the translation that has to be done between the major networks. Again, an Internet e-mail address looks something like this: user@machine.site.domain Any address to a mail gateway is going to be some variation (minor or major) on this theme. X.400 Addressing The Internet uses what is formally known as RFC-822 addressing. Many large commercial services specializing in electronic mail use something known as an X.400 gateway to talk to the Internet. Those addresses look something like this: /A=value/B=value/C=value This style is usable from the Internet, because RFC-822 allows slashes and equals signs. In fact, there's the opposite problem: RFC-822 allows many characters to be used in addressing that cause an X.400 gateway to go into convulsions, including the @ sign. Since this appears in all Internet-style mail addresses, there's an obvious problem. Whenever the Internet address has a special character, you need to use the following translation table: Internet X.400 @ (a) % (p) ! " (q) _ (u) ( (l) ) (r) For any other special character, such as #, substitute (xxx), where xxx is the three-digit decimal ASCII code for the character. For #, you would use (035). For example, to convert the Internet address oldvax!Mutt#Jeff@cartoon.com [...]... picture.tif" 36 8/22606 EOT $ The following set of commands shows how the mail recipient can save and uudecode the contents of the file: $ mailx mailx Revision: 70.7 Date: 92/04/16 15 :39 :44 Type ? for help "/usr/mail/trimblef": 1 message 1 new >N 1 trimblef Sun Apr 27 14 :36 37 6/227 23 tif file ? s file.tif "file.tif" [New file] 37 6/227 23 ? q $ uudecode file.tif $ ls -l total 260 -rw-rw-rw1 trimblef users 22 733 ... contact David Harris by fax in New Zealand at (+64) 3 4 53- 6612 This is a DOS version of the UNIX PINE mail program You can have the same mail interface on your UNIX and DOS platforms PINE's big limitation is that it doesn't support POP3 it only supports IMAP and SMTP For more information on PINE, see the "Common UNIX Mail Programs" section where the UNIX version is discussed To get it, anonymous ftp... improvement over emacs or vi Pre-compiled versions of PINE are available for certain UNIX platforms You can anonymous ftp to ftp://ftp.cac.washington.edu and look in the /mail directory Pre-compiled versions for AIX3.2, HP/UX 9.01, Linux, NeXTstep, Solaris 2.2 (SPARC), and SunOS 4.1 .3 (SPARC) are available in the unix- bin subdirectory under the pine directory If not, you'll need to compile your own... instance, or if your mail computer knows how to use a modem to call your personal computer, but in most cases this isn't done POP3 (Post Office Protocol 3) The standard protocol used by most mail clients to retrieve mail from a remote system is the post office protocol POP3 This protocol enables your mail client to grab new messages, delete messages, and do other things necessary for reading your incoming... program turns the alias into the full name Common UNIX Mail Programs There are dozens of mail programs available for UNIX systems This chapter covers the most popular ones, including mail, mailx, elm, and PINE mail (Berkeley Mail) The mail program is a simple mail user agent that has its roots in the BSD (Berkeley Software Distribution) version of UNIX It is sometimes referred to as Berkeley Mail This... software: 32 -bit Windows and NT (pcp _32 .zip), 16-bit Windows version 3. x (pcp_w16.zip), FTP Inc's PC-TCP (pcp_pct.zip), Novell's LAN Workplace for DOS (pcp_lwp.zip), Sun's PC-NFS (pcp_pcn.zip),and the WATTCP/Packet Driver (pcp_wat.zip) It should be noted that the Winsock versions are not complete Windows application, with a detailed graphical user interface (GUI) The interface is similar to the UNIX and... are much friendlier than those on many UNIX systems What you want is a program that will call the system that receives your mail (or that will connect to it by whatever means necessary), grab all your new mail, and disconnect Then you can read your mail at your leisure and enter new messages If there are any new messages, the program should call your mail system and give it the new messages for delivery... example, 23 lines of output at a time will be sent to the more command After reading the global configuration file, the mailx command reads the user's local configuration file in $HOME/.mailrc The most common types of entries in a local configuration file are display options and defining user aliases The complete set of configuration options is documented in the manual page for mailx TIP: Some UNIX systems... a megabyte In order to install the package, you'll have to compile it and answer a few system configuration questions The menu displayed by elm appears as follows: Mailbox is '/usr/mail/trimblef' with 3 message(s) [Elm revision: 70.85] N 1 2 Apr 27 trimblef Apr 27 trimblef (9) (10) Project status Flyers tickets N 3 Apr 27 trimblef (10) Going away party You can use any of the following commands by pressing... non-alphanumeric characters (such as spaces) with periods (.) Example: Jim_Jones@p4.f3.n2.z1.fidonet.org To Internet: Use standard Internet addressing with a suffix: userid@userid ON gateway The gateway is a special FidoNet site that acts as a gateway to Internet You can use 1:1 /31 unless you find a better one Example: bsmith@wubba.edu ON 1:1 /31 GEnie GEnie is General Electric's commercial information service From . Sun Apr 27 14 :36 37 6/227 23 tif file ? s file.tif "file.tif" [New file] 37 6/227 23 ? q $ uudecode file.tif $ ls -l total 260 -rw-rw-rw- 1 trimblef users 22 733 Apr 27 14 :38 file.tif -rwxrwxrwx. from 198 .3. 200.86: icmp_seq=0. time =3. ms 100 bytes from 198 .3. 200.86: icmp_seq=1. time=4. ms 100 bytes from 198 .3. 200.86: icmp_seq=2. time =3. ms 100 bytes from 198 .3. 200.86: icmp_seq =3. time=5 198 .3. 200.86: icmp_seq=4. time=4. ms 100 bytes from 198 .3. 200.86: icmp_seq=5. time=8. ms 100 bytes from 198 .3. 200.86: icmp_seq=6. time =3. ms 100 bytes from 198 .3. 200.86: icmp_seq=7. time =3. ms 100