matt@oddjob.uchicago.edu (Matt Crawford) (05/03/89)
For a long time now I've been configuring mailers that I touch to "short circuit" bang paths by skipping ahead to the rightmost fully qualified domain name. An occasional look at the queues and logs shows that this practice is saving people many hops and sometimes several days on their mail. But in the last week there have been two independent instances of this practice leading to loops. Both times involved mail to a off-internet site which had a domain name and a single MX record, and both of the mail exchangers sent the mail by UUCP to oddjob with a bang path that included the full domain name. Bang went the mail, back to the listed mail exchanger. I'm sure the quick and popular answer to this problem is "when the listed first hop is a valid connection, take it." But I could counter- argue that the mail exchanger for the target site was poorly chosen if my own site is closer to the target than the exchanger is. (In point of fact, in both cases the generated bang path had more internet sites on it than just mine.) I solicit opinions from anyone who has spent three years or more maintaining mailers in mixed-network environments. ________________________________________________________ Matt Crawford matt@oddjob.uchicago.edu
woods@ncar.ucar.edu (Greg Woods) (05/04/89)
In article <3048@tank.uchicago.edu> matt@oddjob.uchicago.edu (Matt Crawford) writes: >I'm sure the quick and popular answer to this problem is "when the >listed first hop is a valid connection, take it." But I could counter- >argue that the mail exchanger for the target site was poorly chosen if >my own site is closer to the target than the exchanger is. This is another of the practical vs. ideal arguments. As maintainer of one of the sites in question, there is an MX record out there that points *.fidonet.org to my machine. The only service I perform for Fidonet is to convert domain addresses to bang paths. I do not have any physical connections to Fidonet at all. This means someone mails to user@whatever.fidonet.org, my mailer converts this to a bang path to the appropriate UUCP-to-Fido gateway (found from UUCP map data), and mails it out. From what I can see, there are over a dozen such gateways, and each gateway can itself gateway to dozens of Fidonet hosts. To do this the "right" way would require possibly hundreds of MX records. In addition to that, these MX records would have to be maintained by someone else who is providing name server service for fidonet.org (who may or may not themselves be connected to Fidonet). It isn't likely that they could find someone who would volunteer to provide this service under those conditions. Nor would I be willing to do routing if I had to maintain all the info myself. As it happens, they maintain their own info by publishing UUCP map entries for the various hosts. This means that those who benefit do the real work. It's practical this way and impractical to do it any other way. Then we get back to the religious war over whether aggressive rerouting is a good thing or not. No point in arguing it; there are lots of well-respected people on both sides of the issue. I got around the problem by simply deleting oddjob from my list of connections (by putting the -d oddjob flag on pathalias, which will prevent the generation of routes through oddjob from this site; the physical link still exists). End of mail loop. --Greg
nomad@verdix.com (Lee Damon) (05/05/89)
In article <3144@ncar.ucar.edu> woods@handies.UCAR.EDU (Greg Woods) writes: >In article <3048@tank.uchicago.edu> matt@oddjob.uchicago.edu (Matt Crawford) writes: >> [...] I could counter- >>argue that the mail exchanger for the target site was poorly chosen if >>my own site is closer to the target than the exchanger is. > > [...] there is an MX record out there that points >*.fidonet.org to my machine. The only service I perform for Fidonet is >to convert domain addresses to bang paths. [...] This means someone mails to >user@whatever.fidonet.org, my mailer converts this to a bang path to the >appropriate UUCP-to-Fido gateway (found from UUCP map data), and mails >it out. From what I can see, there are over a dozen such gateways, [...] There are over 25 and more on the way. As we have it set up now, if a gateway has a friendly local (or semi-local) internet site willing to gateway for them, I point a MX record at that site and it overrides the *.fidonet.org (lcd as it were) MX. If they don't have a local gateway, then the default one pointing at ncar is used. Of course, I'm always looking for internet sites willing to act as forwarders - it makes things work faster and lowers the load on ncar. If you have such a site, and are willing to help, please contact me! nomad hostmaster, fidonet.org ============= Lee Damon \ work: verdix!nomad or nomad@verdix.com \ play: {agora,tessi,verdix}!castle!nomad or nomad@castle.uucp / \ "God" created man in its image, and man being ever humble returned the favor.