Re: [Evolution] 3.16.3: Failed to refresh folder INBOX,
Clarification: DNS server is hosted on the same test system as evolution client - DNS updates are instantaneous. The expected behavior is to re-query DNS record when connection timeout occurred instead of blindly and indefinitely try the same IP address. Eugene. On Tue, 2015-06-23 at 09:24 +0100, Pete Biggs wrote: Connect to an IMAP server, retrieve email. Move IMAP server to another address, change DNS record, attempt to retrieve email again. Evolution indefinitely keeps trying previous IP address, displaying an error Connection timed out. Yes, sounds reasonable to me - in my experience any changes to DNS records take a little while to settle down. DNS entries have a lifetime - this lifetime is server configurable and can be anything from a few minutes to days depending on how often the administrator of the DNS thinks the entries are likely to change. The lifetime allows the clients to cache the DNS results and most clients won't bother to query the DNS again until the entry would have expired. And it's not an Evolution issue: I very much doubt Evolution is doing the actual DNS lookups - after all, that's what libraries are for. Don't get confused by using utilities such as nslookup - they perform the DNS queries themselves so by-pass the cache. ___ evolution-list mailing list evolution-list@gnome.org To change your list options or unsubscribe, visit ... https://mail.gnome.org/mailman/listinfo/evolution-list
Re: [Evolution] 3.16.3: Failed to refresh folder INBOX,
On Tue, 2015-06-23 at 17:53 -0600, Zan Lynx wrote: On 06/23/2015 02:24 AM, Pete Biggs wrote: Don't get confused by using utilities such as nslookup - they perform the DNS queries themselves so by-pass the cache. Only if you tell them to do so. By default dig and nslookup do the query to the same resolver IP that the system libraries use. This isn't the place to argue about DNS lookups. But yes, they use the same DNS server by default, but nslookup doesn't use the system name services for the query, it talks directly to the DNS servers. Hence it by-passes any system cache, which was my point. I can see it doing it using strace and you can change the DNS server it queries from within the program so it can't just hand off the queries to the OS. If there is a cache in use, it is inside the Evolution libraries. No, as Milan said, Evolution doesn't cache the queries, all such network activities are handled by other libraries. If a command-line ping, dig, or host command returns the new IP for a DNS name, Evolution should be using that as well. Not necessarily, it depends on the individual libraries being used. If it does not, that would be a bug. Not necessarily. The DNS entry has a lifetime, it is not at all unreasonable for the client to assume that the name-IP mapping is valid for the entirety of the lifetime. That's the whole point of it - i.e. to reduce the number of DNS queries necessary by caching the results. P. ___ evolution-list mailing list evolution-list@gnome.org To change your list options or unsubscribe, visit ... https://mail.gnome.org/mailman/listinfo/evolution-list
Re: [Evolution] 3.16.3: Failed to refresh folder INBOX,
On Wed, 2015-06-24 at 18:05 +0100, Pete Biggs wrote: On Wed, 2015-06-24 at 16:59 +0100, Patrick O'Callaghan wrote: On Wed, 2015-06-24 at 10:38 +0100, Pete Biggs wrote: command-line ping, dig, or host command returns the new IP for a DNS name, Evolution should be using that as well. [[I wish they would fix this line wrapping of quoted content ...]] Not necessarily, it depends on the individual libraries being used. Strictly that is true, but one would expect a reasonably configured system to use a single resolver library for everything. Usually that is libresolv.so, which is part of glibc. No, that's just not so, it's much more complex than that. Most user programs, like ping, use routines like 'gethostbyname' (or their more modern equivalent) - those routines get their information from a variety of sources - /etc/hosts, YP/NIS, DNS - which ultimately might use libresolv. Gnome applications tend to use the GIO libraries. And DNS querying programs like nslookup, host and dig go directly to the DNS server. On my system (Fedora 22) nslookup and evolution both link to libresolv, though ping doesn't. Things are complicate further by systems such as nscd - Name Service Cache Daemon that, as it says in the man page, provides a cache for the most common name service requests - and that includes hosts. The default TTL for hosts in nscd is 1 hour. I stopped using nscd when I moved away from Sun workstations so who knows. That's why I said in reply to the original poster that you need to be careful about using things like nslookup to verify DNS entries since other parts of the system may be caching previous results. I don't dispute that. poc ___ evolution-list mailing list evolution-list@gnome.org To change your list options or unsubscribe, visit ... https://mail.gnome.org/mailman/listinfo/evolution-list
Re: [Evolution] 3.16.3: Failed to refresh folder INBOX,
On Wed, 2015-06-24 at 10:38 +0100, Pete Biggs wrote: command-line ping, dig, or host command returns the new IP for a DNS name, Evolution should be using that as well. Not necessarily, it depends on the individual libraries being used. Strictly that is true, but one would expect a reasonably configured system to use a single resolver library for everything. Usually that is libresolv.so, which is part of glibc. I suppose running in a chroot environment, or in a VM, could change that. poc ___ evolution-list mailing list evolution-list@gnome.org To change your list options or unsubscribe, visit ... https://mail.gnome.org/mailman/listinfo/evolution-list
Re: [Evolution] 3.16.3: Failed to refresh folder INBOX,
On Wed, 2015-06-24 at 16:59 +0100, Patrick O'Callaghan wrote: On Wed, 2015-06-24 at 10:38 +0100, Pete Biggs wrote: command-line ping, dig, or host command returns the new IP for a DNS name, Evolution should be using that as well. [[I wish they would fix this line wrapping of quoted content ...]] Not necessarily, it depends on the individual libraries being used. Strictly that is true, but one would expect a reasonably configured system to use a single resolver library for everything. Usually that is libresolv.so, which is part of glibc. No, that's just not so, it's much more complex than that. Most user programs, like ping, use routines like 'gethostbyname' (or their more modern equivalent) - those routines get their information from a variety of sources - /etc/hosts, YP/NIS, DNS - which ultimately might use libresolv. Gnome applications tend to use the GIO libraries. And DNS querying programs like nslookup, host and dig go directly to the DNS server. Things are complicate further by systems such as nscd - Name Service Cache Daemon that, as it says in the man page, provides a cache for the most common name service requests - and that includes hosts. The default TTL for hosts in nscd is 1 hour. That's why I said in reply to the original poster that you need to be careful about using things like nslookup to verify DNS entries since other parts of the system may be caching previous results. P. ___ evolution-list mailing list evolution-list@gnome.org To change your list options or unsubscribe, visit ... https://mail.gnome.org/mailman/listinfo/evolution-list
Re: [Evolution] 3.16.3: Failed to refresh folder INBOX,
Am Mittwoch, den 24.06.2015, 18:05 +0100 schrieb Pete Biggs: On Wed, 2015-06-24 at 16:59 +0100, Patrick O'Callaghan wrote: On Wed, 2015-06-24 at 10:38 +0100, Pete Biggs wrote: command-line ping, dig, or host command returns the new IP for a DNS name, Evolution should be using that as well. [[I wish they would fix this line wrapping of quoted content ...]] +1 - but, who are they ... ___ evolution-list mailing list evolution-list@gnome.org To change your list options or unsubscribe, visit ... https://mail.gnome.org/mailman/listinfo/evolution-list
Re: [Evolution] 3.16.3: Failed to refresh folder INBOX,
Hi, On Wed, 2015-06-24 at 19:19 +0200, Tom wrote: Am Mittwoch, den 24.06.2015, 18:05 +0100 schrieb Pete Biggs: On Wed, 2015-06-24 at 16:59 +0100, Patrick O'Callaghan wrote: On Wed, 2015-06-24 at 10:38 +0100, Pete Biggs wrote: command-line ping, dig, or host command returns the new IP for a DNS name, Evolution should be using that as well. [[I wish they would fix this line wrapping of quoted content ...]] +1 - but, who are they ... ...those reading GNOME's bugzilla for Evolution bugs against Composer component. :) The question is what is correct. Either the cited text can be treated as Preformatted, which means the line character-width will go beyond the limit (set to 72 characters by default), or the lines will wrap in this odd way. There was a code to merge such wrapped lines and make then a nice flowing paragraph, but that also doesn't always produce the right code, because it's hard to know whether the line break is due to line limitation or intended by the writer (aka there are too many corner cases). Bye, Milan ___ evolution-list mailing list evolution-list@gnome.org To change your list options or unsubscribe, visit ... https://mail.gnome.org/mailman/listinfo/evolution-list
Re: [Evolution] 3.16.3: Failed to refresh folder INBOX,
On Tue, 2015-06-23 at 08:56 +0200, Milan Crha wrote: On Mon, 2015-06-22 at 19:11 -0400, Eugene Kanter wrote: Evolution indefinitely keeps trying previous IP address, displaying an error Connection timed out. I see a very similar behaviour with the Firefox, when the network changes, it only may have set slightly shorter timeouts. Ditto, I would not expect this kind of change to work 'normally' as it is not a normal change. If you need to do this kind of thing regularly [why?] I would recommend using a script or NetworkManager to cause an offline/online event, or else use a virtual machine. -- Adam Tauno Williams mailto:awill...@whitemice.org GPG D95ED383 Systems Administrator, Python Developer, LPI / NCLA ___ evolution-list mailing list evolution-list@gnome.org To change your list options or unsubscribe, visit ... https://mail.gnome.org/mailman/listinfo/evolution-list
Re: [Evolution] 3.16.3: Failed to refresh folder INBOX,
On 06/24/2015 11:05 AM, Pete Biggs wrote: Gnome applications tend to use the GIO libraries. And DNS querying programs like nslookup, host and dig go directly to the DNS server. Things are complicate further by systems such as nscd - Name Service Cache Daemon that, as it says in the man page, provides a cache for the most common name service requests - and that includes hosts. The default TTL for hosts in nscd is 1 hour. The only time I see references to nscd is in horrible confusing bugs. If they ignore the DNS TTL and set it to 1 hour I can see why. I sure hope that GIO hasn't copied that stupid idea. A more probable GIO user bug is doing the resolve and saving the address object for later use, never considering that the IP will be different next time. ___ evolution-list mailing list evolution-list@gnome.org To change your list options or unsubscribe, visit ... https://mail.gnome.org/mailman/listinfo/evolution-list
Re: [Evolution] 3.16.3: Failed to refresh folder INBOX,
On Wed, 2015-06-24 at 10:38 +0100, Pete Biggs wrote: On Tue, 2015-06-23 at 17:53 -0600, Zan Lynx wrote: On 06/23/2015 02:24 AM, Pete Biggs wrote: If it does not, that would be a bug. Not necessarily. The DNS entry has a lifetime, it is not at all unreasonable for the client to assume that the name-IP mapping is valid for the entirety of the lifetime. That's the whole point of it - i.e. to reduce the number of DNS queries necessary by caching the results. If it is a bug then it is a bug in MANY libraries and applications used on a wide variety of platforms [not just GNOME/LINUX]. It likely means nginx and squid are categorically broken. The DNS lifetime determines how long it is cached by another DNS server or a resolver. Clients do not much care about TTL. It is very common - if not expected - for clients to *assume* that DNS look-up results are essentially static. -- Adam Tauno Williams mailto:awill...@whitemice.org GPG D95ED383 Systems Administrator, Python Developer, LPI / NCLA ___ evolution-list mailing list evolution-list@gnome.org To change your list options or unsubscribe, visit ... https://mail.gnome.org/mailman/listinfo/evolution-list
Re: [Evolution] 3.16.3: Failed to refresh folder INBOX,
On Mon, 2015-06-22 at 19:11 -0400, Eugene Kanter wrote: Move IMAP server to another address, change DNS record Hi, these are low-level things users usually cannot do, right? I mean, you can change a local network, like unplug the wire and connect using WiFi, but the server address will stay the same, including the DNS record, no? Evolution indefinitely keeps trying previous IP address, Right. There is done some caching of the route, not directly in evolution, but in GIO streams/gnutls/..., which evolution relies on. it also relies on the network change notifications, which are received through GNetworkMonitor. There can be an issue in the IMAPx code, how it processes the network change notifications. displaying an error Connection timed out. What happens next? Does the IMAP account reconnect properly after this timeout error when you try to do anything else with it (or the same action with it)? I see a very similar behaviour with the Firefox, when the network changes, it only may have set slightly shorter timeouts. Bye, Milan ___ evolution-list mailing list evolution-list@gnome.org To change your list options or unsubscribe, visit ... https://mail.gnome.org/mailman/listinfo/evolution-list
Re: [Evolution] 3.16.3: Failed to refresh folder INBOX,
On 06/23/2015 02:24 AM, Pete Biggs wrote: Don't get confused by using utilities such as nslookup - they perform the DNS queries themselves so by-pass the cache. Only if you tell them to do so. By default dig and nslookup do the query to the same resolver IP that the system libraries use. If there is a cache in use, it is inside the Evolution libraries. If a command-line ping, dig, or host command returns the new IP for a DNS name, Evolution should be using that as well. If it does not, that would be a bug. Because IP addresses do get changed now and then, and users with laptops rarely close email programs when you can just leave programs open and suspend/resume the machine. ___ evolution-list mailing list evolution-list@gnome.org To change your list options or unsubscribe, visit ... https://mail.gnome.org/mailman/listinfo/evolution-list
