projects / exim.git / blame
| Commit | Line | Data |
|---|---|---|
| e0f3765a PH |
1 | Date: Wed, 22 Nov 2000 17:51:42 -0500 (EST) |
| 2 | From: Dave C. <djc@microwave.com> | |
| 3 | ||
| 4 | [Syntax converted for Exim 4 by PH, 06-Dec-2001. Unchecked.] | |
| 5 | ||
| 6 | Ok.. Ive come up with something which might be worth including in the | |
| 7 | cookbook. Credit where it is due, the idea for this came from Nigel's | |
| 8 | C014. | |
| 9 | ||
| 10 | I have a setup to support ETRN for a few small (ok, two) domains. | |
| 11 | Currently it just leaves all the mail in the exim spool, and uses the | |
| 12 | default exim etrn response to flush it out. | |
| 13 | ||
| 14 | I don't like that - I agree with the opinion expressed on the list that | |
| 15 | mail should be delivered somewhere else, and then shoved down an SMTP | |
| 16 | session by some other program. Ive searched far and wide for something | |
| 17 | suitable to do that shoving, and finally hit upon the only program I | |
| 18 | trust to do that, handling errors and rejections correctly - exim | |
| 19 | itself. | |
| 20 | ||
| 21 | Nigel's solution for 'situation where a site I MX for has a known | |
| 22 | outage', combined with a bit of bash scriptery, seems to form a neat | |
| 23 | solution. (An intermittently connected host sort of falls under the | |
| 24 | 'known outage' category ;) | |
| 25 | ||
| 26 | Without any further fluff, here are the details. Additional comments | |
| 27 | appear below.. | |
| 28 | ||
| 29 | Either the real (intermittently connected) destination host needs to be | |
| 30 | listed as the lowest MX (with the exim server as a less preferred) , or | |
| 31 | the exim server needs to be the lowest MX, but have a router before the | |
| 32 | lookuphost router which uses route_list or something appropriate to | |
| 33 | normally deliver mail to the dialup host. The former is probably better | |
| 34 | for a host which is usually connected and is only occasionally | |
| 35 | disconnected (since other hosts would be able to delivery directly most | |
| 36 | of the time, skipping an extra relay), while the latter would probably | |
| 37 | work better for the converse ;) This paragraph actually applies anytime | |
| 38 | you are using ETRN.. | |
| 39 | ||
| 40 | In either case, the routers below must precede whatever router handles | |
| 41 | the normal direct-to-dialup-destination.. | |
| 42 | ||
| 43 | -- | |
| 44 | ||
| 45 | smtp_etrn_command = /etc/exim/etrn_script $domain | |
| 46 | ||
| 47 | [- Content of /etc/exim/etrn_script: -] | |
| 48 | #!/bin/sh | |
| 49 | ||
| 50 | # Where exim lives | |
| 51 | EXIM=/usr/sbin/exim | |
| 52 | ||
| 53 | # Something appropriate to generate a temporary unique string | |
| 54 | UNIQ=`head -c100 /dev/urandom | md5sum | cut -f 1 -d" "` | |
| 55 | ||
| 56 | arg=$1 | |
| 57 | domain=`echo $arg | sed 's/^\#//g'` | |
| 58 | ||
| 59 | if ( test -f /var/spool/etrn/${domain} ); then | |
| 60 | exim_lock -q /var/spool/etrn/${domain} "mv /var/spool/etrn/${domain} /tmp/etrn-bsmtp-${UNIQ}" | |
| 61 | ( cat /tmp/etrn-bsmtp-${UNIQ} | |
| 62 | echo "QUIT" ) | $EXIM -bS -oMr etrn_requeue | |
| 63 | rm -f /tmp/etrn-bsmtp-${UNIQ} | |
| 64 | fi | |
| 65 | ||
| 66 | $EXIM -R $domain | |
| 67 | ||
| 68 | [- end of etrn_script -] | |
| 69 | ||
| 70 | [- exim transport -] | |
| 71 | ||
| 72 | bsmtp_for_etrn: | |
| 73 | driver=appendfile | |
| 74 | file=/var/spool/etrn/$domain | |
| 75 | user=exim | |
| 76 | batch_max = 1000 | |
| 77 | use_bsmtp | |
| 78 | ||
| 79 | [- routers -] | |
| 80 | [- You probably would want to put the domains in a file or a dbm and | |
| 81 | [- adjused the 'domains' setting appropriately for both of these.. | |
| 82 | ||
| 83 | # If any message has already been delivered to the bsmtp file, | |
| 84 | # this will detect the existence of the file and all messages will | |
| 85 | # go there, regardless of age. | |
| 86 | etrn_already: | |
| 87 | driver = accept | |
| 88 | transport = bsmtp_for_etrn | |
| 89 | require_files = /var/spool/etrn/$domain | |
| 90 | domains = etrntest.somedomain.com | |
| 91 | ||
| 92 | # If a message has been on the queue for over the specified amount of | |
| 93 | # time, this will catch it and drop it into the bsmtp file | |
| 94 | etrn_delay: | |
| 95 | driver = accept | |
| 96 | transport = bsmtp_for_etrn | |
| 97 | condition = ${if >{$message_age}{1800} {yes}{no}} | |
| 98 | domains = etrntest.somedomain.com | |
| 99 | ||
| 100 | [- -] | |
| 101 | ||
| 102 | Basically, this setup lets exim try to deliver to the real host for up | |
| 103 | to whatever time is specified in the \%etrn_delay%\ router. (1800 seconds = | |
| 104 | 30 minutes), and then delivers all waiting messages, and any further | |
| 105 | messages, directly to a BSMTP file. This setup uses one big BSMTP | |
| 106 | file per domain, it probably wouldnt be too complex to have it use separate | |
| 107 | files. | |
| 108 | ||
| 109 | When the \^etrn_script^\ runs, it locks and renames the BSMTP file, and | |
| 110 | reinjects the messages to Exim, which (presumably) will now be able to | |
| 111 | deliver them. If it can't, then once they are too old they will again | |
| 112 | be sent off to the BSMTP file.. (If for som reason this occurs over and | |
| 113 | over without Exim being able to deliver them, eventually the messages | |
| 114 | will be returned with \*too many Received headers*\; this is a good | |
| 115 | thing, since their age will never get high enough for them to be | |
| 116 | returned by any retry rules). |