Re: Preventing DNS lookup prior to sending 220 banner in exim4 on etch
On Tue, 17 Jun 2008 17:34:02 +0200, [EMAIL PROTECTED] ([EMAIL PROTECTED]) wrote: I have exim4 (exim4-daemon-heavy) running on etch. This machine has only a few users who send directly. One of them has an ISP who seems to have a broken DNS setup. The symptom I see is that when this user connects to the server (port 25 or 587) there is a large delay before the 220 banner is shown e.g.: [snip] Is it possible to whitelist a range or turn off the check? There is a debconf option that minimizes DNS lookups. It should solve this problem, but it might disable the lookups also in places where you might want them. In any case, you can change the value of that option with dpkg-reconfigure exim4-config or by editing /etc/exim4/update-exim4.conf.conf . -- Eduardo M KALINOWSKI [EMAIL PROTECTED] -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: Preventing DNS lookup prior to sending 220 banner in exim4 on etch
On Tue, Jun 17, 2008 at 01:37:59PM -0300, Eduardo M KALINOWSKI wrote: On Tue, 17 Jun 2008 17:34:02 +0200, [EMAIL PROTECTED] ([EMAIL PROTECTED]) wrote: I have exim4 (exim4-daemon-heavy) running on etch. This machine has only a few users who send directly. One of them has an ISP who seems to have a broken DNS setup. The symptom I see is that when this user connects to the server (port 25 or 587) there is a large delay before the 220 banner is shown e.g.: [snip] Is it possible to whitelist a range or turn off the check? There is a debconf option that minimizes DNS lookups. It should solve this problem, but it might disable the lookups also in places where you might want them. OK - just tried that. Seems to set the host_lookup to empty instead of * and yes - the 220 banner is now instant. I wonder if there is a way to say that host_lookup is everything except a range though? It would be great to be able to say all hosts except the IPs in this ISP's dial up ranges. Anyhow - I'm going to leave it running for a couple of weeks (am off net for two weeks soon) and will see if it causes any issues. Thanks for your pointer ;) -- Chris Searle -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: Preventing DNS lookup prior to sending 220 banner in exim4 on etch
On Tue, Jun 17, 2008 at 08:32:15PM +0200, [EMAIL PROTECTED] wrote: On Tue, Jun 17, 2008 at 01:37:59PM -0300, Eduardo M KALINOWSKI wrote: On Tue, 17 Jun 2008 17:34:02 +0200, [EMAIL PROTECTED] ([EMAIL PROTECTED]) wrote: I have exim4 (exim4-daemon-heavy) running on etch. This machine has only a few users who send directly. One of them has an ISP who seems to have a broken DNS setup. The symptom I see is that when this user connects to the server (port 25 or 587) there is a large delay before the 220 banner is shown e.g.: [snip] Is it possible to whitelist a range or turn off the check? There is a debconf option that minimizes DNS lookups. It should solve this problem, but it might disable the lookups also in places where you might want them. OK - just tried that. Seems to set the host_lookup to empty instead of * and yes - the 220 banner is now instant. I wonder if there is a way to say that host_lookup is everything except a range though? It would be great to be able to say all hosts except the IPs in this ISP's dial up ranges. I think you can do that directly in the exim.conf file, but that would more or less require a handwritten file. It's not that hard, but definitely an order of magnitude more difficult than using debconf. There may be a way to add additional lines to the debconf config as well, which would help. You should read the exim documentation (heh) for more details. A signature.asc Description: Digital signature
