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Re: [ALUG] more about sendmail
by mbm 13 Nov '07

13 Nov '07

>> You shouldn't use a CNAME for a host that you want to receive mail. I >> suggest you try changing it to an A record instead. > > To quote RFC1123 section 5.2.2: > > The domain names that a Sender-SMTP sends in MAIL and RCPT commands MUST > have been "canonicalized," i.e., they must be fully-qualified principal > names or domain literals, not nicknames or domain abbreviations. A > canonicalized name either identifies a host directly or is an MX name; it > cannot be a CNAME. > > Can someone explain why this restriction exists (or point to a good resource)? One obvious point is DNS inefficiency. If the sending MTA gets back an answer to an MX query pointing to a CNAME it then has to query again to get the A record. If there is a CNAME chain (and there may well be) then there have to be multiple queries until the A record is reached. Check out the Bat book. Mick

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More about sendmail sending to local machine
by Chris G 13 Nov '07

13 Nov '07

I'm beginning to think this is impossible! :-) I've been doing some Google searching about the file local-host-names, one hit suggested trying the following to see what sendmail views as local domains:- echo '$=w' | sendmail -bt ... and what does it return .... ADDRESS TEST MODE (ruleset 3 NOT automatically invoked) Enter <ruleset> <address> > home home.isbd.net localhost [192.168.1.1] isbd.net Which certainly looks as if sendmail thinks that home.isbd.net is the local machine. However when I tried using 'mail' to send a message from root to chris(a)home.isbd.net (I used 'mail' to ensure little else was involved) it *still* tries to send it out to the outside world. The entries in maillog are:- Nov 11 11:38:20 home sendmail[7883]: lABBcJ9h007883: from=root, size=64, class=0, nrcpts=1, msgid=<200711111138.lABBcJ9h007883(a)home.isbd.net>, relay=root@localhost Nov 11 11:38:20 home sendmail[7884]: lABBcKac007884: from=<root(a)home.isbd.net>, size=354, class=0, nrcpts=1, msgid=<200711111138.lABBcJ9h007883(a)home.isbd.net>, proto=ESMTP, daemon=MTA, relay=localhost.localdomain [127.0.0.1] Nov 11 11:38:20 home sendmail[7883]: lABBcJ9h007883: to=chris(a)home.isbd.net, ctladdr=root (0/0), delay=00:00:01, xdelay=00:00:00, mailer=relay, pri=30064, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (lABBcKac007884 Message accepted for delivery) Nov 11 11:40:20 home sendmail[7886]: lABBcKac007884: to=<chris(a)84-45-228-40.no-dns-yet.enta.net>, delay=00:02:00, xdelay=00:02:00, mailer=esmtp, pri=120354, relay=84-45-228-40.no-dns-yet.enta.net. [84.45.228.40], dsn=4.0.0, stat=Deferred: Connection timed out with 84-45-228-40.no-dns-yet.enta.net. -- Chris Green

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How to send mail locally, solved but I don't really understand why
by Chris G 11 Nov '07

11 Nov '07

Well I finally found a way to send mail to local recipients, quite by chance really. I have a POP3 mailbox set up at Gradwell.net to allow me to send mail to 'myself' on my home machine (I read just about all of my mail on a remote machine at Gradwell) which comes in useful occasionally when I want to send a file to my home Linux box. This is set up in my isbd.net on Gradwell so it's home(a)isbd.net. I just occasionally run mutt locally on my desktop machine and collect mail from this POP3 mailbox. So, I realised that one way around my problem of sending mail to myself on the desktop machine would be to put home(a)isbd.net as the alias for root mail in /etc/aliases. Before doing this I tried sending mail to home(a)isbd.net from my desktop machine, it failed with "Error sending message, child exited 67 (User unknown.).", huh? I then realised that this meant that sendmail was trying to send this *locally* and there's no user called 'home' on this machine. Euraka!!! If I send mail to chris(a)isbd.net on my desktop machine it gets sent to the local user chris and *not* to the place where it would get sent if it was sent from anywhere else on the internet (chris(a)isbd.net is one of my 'real' E-Mail addresses). So, problem solved, I can put:- root: chris(a)isbd.net at the end of /etc/aliases and all the root mail will get to me locally. Quite *why* it's like this is anybody's guess! :-) -- Chris Green

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How to get mail to local destinations delivered?
by Chris G 11 Nov '07

11 Nov '07

I have a fairly default Fedora 7 installation, certainly the sendmail is just as it was installed. How do I get sendmail to deliver mail to local destinations? The system's hostname is home.isbd.net and it's connected to the Internet via a router. I have a CNAME set up at the hosting provider that hosts isbd.net to point at the static address of my ADSL connection. When I send mail from my system to a local address it gets the hostname added, thus mail gets sent to root(a)home.isbd.net, postmaster(a)home.isbd.net, chris(a)home.isbd.net, etc. All of this fails because sendmail attempts to connect to the SMTP port of home.isbd.net, which isn't possible because my router's firewall doesn't accept connections on port 25. I don't want to open up port 25 and it seems a bit silly anyway to send mail on such a long round trip. Is there any way I can tell sendmail that home.isbd.net is localhost (or 192.168.1.1)? I have an entry for home.isbd.net in my /etc/hosts file which is:- 192.168.1.1 home home.isbd.net but obviously sendmail is doing a DNS lookup for home.isbd.net which returns the 'external' IP address. -- Chris Green

5 7

Regex
by Ruth Bygrave 11 Nov '07

11 Nov '07

In a more-stupid-than-normal moment I ended up with a Text Edit document on my Mac with lots of capital I's in the middle of words. I tried 'check spelling' to see if it did an entire run of spell- checking through the document, but there was no dialog box. Tried to go through it in NeoOffice, which I'm not that familiar with, but NeoOffice bombed. Can somebody less brain-dead than I appear to be today come up with a bash script to pour the text into that does 'replace I not on word boundary with i'? (The infuriating thing is, I used to *know* this stuff, or at least where to look it up, but because I've been Abjuring Hackish Unixy Things since I was in mental hospital this summer, I don't even know where to start...) Also 'replace 'fI ind' with 'I find', because the reason I was messing about with I's in the first place was there's a timing error with my Alphasmart Neo keyboard and it has a tendency to transpose letters. Kthxbai, Ruth

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Samba question/problem
by Chris G 07 Nov '07

07 Nov '07

I have Samba installed and working on my Fedora system, it mostly does what I expect but one entry doesn't. My smb.conf file has:- # global section default service = default encrypt passwords = yes null passwords = yes workgroup = IBMPEERS nt acl support = no [snip] # # # ISBD, user is set to isbd to allow read/write # [isbd] comment = ISBD force user = isbd path = /home/isbd guest ok = yes writable = yes By my reading of the smb.conf manual page that should allow anyone in to access /home/isbd, it should make them act as the user 'isbd' and it should give write access. (Remember this is a home intranet, two users, who both want access to the ISBD files) In practice when connecting from XP I always seem to have to enter a valid password to get access. In general what's the easiest way to make Samba shares appear in XP 'automagically' without having to enter passwords etc.? -- Chris Green

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Python question about reading files
by Chris G 06 Nov '07

06 Nov '07

Are there any Python people here? How do I do the equivalent of the C below in Python :- while ( (str = read(file)) != NULL) { do something; } I can read the data OK, i.e. I have opened the file and I can successfully read from the file with the line:- tagNum = tlvFile.read(3) but I don't see how to make that part of a for/while loop that exits at the end of the file. I can't use an iterator because the file is read in variable length chunks whose length depends on context. -- Chris Green

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BBC on amarok or whatever, how to?
by Peter Alcibiades 06 Nov '07

06 Nov '07

I'm seeking (for someone else) to get streaming BBC to play over some Linux player, don't really care what, on 64bit Debian. Once more cursing the day I ever installed 64 rather than 32bit, and on more than one machine, but that's another story. Amarok, attempting to tune into (for example) mms://wmlive-acl.bbc.co.uk/wms/radio1/radio1_nb_e1s1 gives the response Error loading media, there is no available decoder. I set up amarok in accordance with these instructions: http://www.linuxforums.org/forum/gaming-games-multimedia-entertainment/7934… and presumably having got to the point of trying to play, probably did it right. Assuming this is because there is no win codecs, I went to medubuntu and got the 32 bit ones. This was a large weighty package. They will not install being 32bit. OK, went back and got the 64 bit amd64 ones. This was a suspiciously small file, and one's fears were realized when the package installed and the message was unchanged. I have also downloaded Real Player, and made it executable, but now what to do with it? It too of course is 32bit and presumably that is why it will do zip when you try to start it. There is no problem downloading the mp3 files for previously broadcast programmes, and they play just fine (rhythmbox seems to be an acceptable interface for this). But what I'm really being asked to provide is streaming BBC internet radio. Anyone done it? Peter

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How do people here manage updates (or not)?
by Chris G 06 Nov '07

06 Nov '07

Now that I have been running Fedora 7 for a while I'm beginning to see its strengths and weaknesses. One area that worries me slightly is what seems to be the 'normal' way of keeping it up to date which is to run 'yum update all' (or an equivalent) automatically at regular intervals. Most of the time this works fairly smoothly but every so often there is a hiccough and you see as a result hundreds of messages in the Fedora mailing lists saying "it's broken". For me one of the major disadvantages of this approach is that when the kernel gets updated (which is quite frequently) I have to recompile both my Nvidia display drivers and Vmware. The Vmware recompile can be a bit difficult as Vmware is only guaranteed to build against certain kernel versions and you often have to use third-party patches to get it to compile with more recent kernels. So I don't update all the time now, at least not the kernel. I'm wondering if there is a 'happy medium' somewhere between Slackware which was very conservative and stable (only went to a 2.6 kernal just recently) and Fedora which seems a bit frantically on the bleeding edge. Is there a distribution which offers pretty close to latest versions of everything when it releases but then just maintains things with only security updates and such until the next release? General requirements are:- Not too "GUI and Windows oriented", Fedora is definitely as far as I'd want to go in this direction. A reasonably good package management utility, Fedora's yum makes life a lot easier than Slackware. I run FVWM2 as my window manager so any distribution that makes it difficult to do this is out! Must run Vmware fairly smoothly, I think most probably will, Slackware was slightly messy because of its different initialisation script structure. Vmware is important to me as I need MS Access to run our company's accounts. Running them via Vmware on my desktop is just *so* much nicer than running on a separate machine that I'll never go back. It's all well backed up and, if the Linux/Vmware goes completely pear shaped I could easily enough just put them on a dedicated machine so absolute reliability of Vmware isn't necessary. -- Chris Green

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Re: [ALUG] How should my hostname *really* be configured
by mbm 05 Nov '07

05 Nov '07

Chris > > I have a CNAME record in the zone file at the hosting provider that > hosts isbd.net so that home.isbd.net has the address > 84-45-228-40.no-dns-yet.enta.net which is my home machine (via ADSL). I'm assuming that enta.net give you a fixed IP address here. It certainly looks that way from their website. So the external world view of your "home.isbd.net" server will be OK and will resolve to the external address of your ADSL router. I also assume that you are either port forwarding 22 and 80 to your "home" machine or have it publicly available on a DMZ. > > So far so good, it all does basically what I want so that I can 'ssh > home.isbd.net' and log in to my home machine and http://home.isbd.net > in a browser gets to see the apache web pages on my home machine. > > > However I still don't seem to have the 'local' setup fully sorted, > i.e. how do I get things on my local intranet to work totally > correctly? As it is things work but there are some 'infelicities'. > > > In particular apache when it starts up has the message about "Could > not reliably determine the server's fully qualified domain name ...." > and I'd like to know the proper way to get the result of 'hostname' to > be right. Ther apache error is probably not a DNS issue, but more likely caused by a configuration problem in apache2.conf (or httpd.conf). Try setting the ServerName directive to the FQDN "home.isbd.net". Apache will then use that and should stop complaining. > My home network is behind a router and most machines have static IP > addresses in the 192.168.1 range, the router is set up to allow ssh > and http through (with limitations). > > In my /etc/hosts file I have:- > > 127.0.0.1 localhost.localdomain localhost > ::1 localhost6.localdomain6 localhost6 > 192.168.1.1 home home.isbd.net > 192.168.1.5 garage > 192.168.1.10 chris > 192.168.1.40 netpr > 192.168.1.44 hp7310 HPEDDBB7 HP000D9D068F7D > 192.168.1.254 speedtouch > > Searching in google suggests that I need to add my proper hostname > (i.e. home.isbd.net) to the 127.0.0.1 line in /etc/hosts but that > sounds like it's incompatible with the 192.168.1.1 line. I recommend you don't alias your hostname to local loopback. Leave that to localhost. The 192.168.1.1 entry is fine. So long as all your hostfiles are in synch and your machines all look at local hosts files first (/etc/host.conf says "order hosts,bind") then they will all resolve "home.isbd.net" to 192.168.1.1. Alternatively you could run a local DNS server (possibly on your router) but for a small network that is probably more hassle than it is worth. > I want to end up in a situation where:- > > /bin/hostname returns 'home' (as opposed to home.isbd.net, so that > my prompts and window titles are sensible) > > home.isbd.net is a valid address on my local network and connects > to the linux server machine > > There are no complaints from apache (or others) at startup Just set each hostname locally to "foo" and ensure that /etc/hosts has alias entries for "foo.bar.net" as appropriate. Your example hosts file is fine, but you should have aliases for "garage.isbd.net", "chris.isbd.net" etc. to ensure proper resolution. HTH Mick

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