The two messages I read with the above subject seem to overlook some important concepts:
a) Like many many servers, openser is a high-level application. It depends on a complicated under-world of services and protocols. The operation of it depends on many external elements, all of which should be in good working order.
b) DNS resource records (RR) have time-to-live (TTL) attributes. Any application may cache RR up to the length of time specified by the TTL. When you restart something, you typically blow away the cache and start over. In general, most applications do not cache general name lookups, since that is a lower-level function. However, an application caching the hostname it's on and/or IP addresses to bind to is standard practice.
I have come to realise that it seems as though once loaded into memory and running, openser "caches" the config file and also does not appear to re-check for changes in network conditions
Yes, isn't that great! It shouldn't check until either told to by a human or when the underlying protocol indicates that it is time for a refresh (like a DNS TTL expiring).
Regarding this:
I had to lock-down the network card to 10mbit full-duplex. It was autoselecting 100mbit half-duplex. Hope that helps someone... sometime...
Autoselecting 100/half probably means that the link auto-negotiation failed, as that is the default. It might fail because the other side was nailed down, perhaps to 10/full. That seems like an unlikely choice... but one reason why it might be nailed at 10mbits is because someone before you couldn't get it to run well at 100mbits and discovered that setting it to 10 was a "solution." If that was the case, I'ld guess that the cable between the switch and the server is lengthy and that it was not tied down in the prescribed order (wO, O, wG, Bl, wBl, G, wBr, Br) [or swap O and G].
I apologize if this email comes across as a little snooty. This is my first email of the day and I often have trouble phrasing things in a nice way prior to my coffee kicking in.
-mark
On Thursday 19 October 2006 17:25, Mark Kent wrote:
I had to lock-down the network card to 10mbit full-duplex. It was autoselecting 100mbit half-duplex. Hope that helps someone... sometime...
Autoselecting 100/half probably means that the link auto-negotiation failed, as that is the default. It might fail because the other side was nailed down, perhaps to 10/full. That seems like an unlikely choice... but one reason why it might be nailed at 10mbits is because someone before you couldn't get it to run well at 100mbits and discovered that setting it to 10 was a "solution." If that was the case, I'ld guess that the cable between the switch and the server is lengthy and that it was not tied down in the prescribed order (wO, O, wG, Bl, wBl, G, wBr, Br) [or swap O and G].
Hi, Locking it to 10/full was what the MCI technician recommended after I opened a ticket because the line was dropping to 500Kbs up/down. This was a 4Mbit up/down line burstable to 10. They said it was not possible to increase the capacity of this line, so I guess they are using their old 10Mbit equipment for this. Since locking it like they asked speed has been fine, and the cable is a 2 meter factory made one plugging into the datacenter patch-panel, so I don't think that's a problem...
Thanks for the tips though.
Richard
I was merely making the point that seemingly openser-related problems are not always to do with openser itself, as in the past whenever restarting openser has failed, I have always assumed it was an entry I may have mistakenly changed in the openser config.
I then came to realise this was not always the case when I started making backup copies of my openser configs and after reverting back to them still could not get openser to restart. It then became apparent that there were other (external) factors or conditions which could affect openser restarting or, in general, simply slow it down as reported above. To make an exhaustive list of all these factors would be a futile exercise, nevertheless, it is something worth bearing in mind and certainly something to bring to the attention of others experiencing similar problems.
Once we all understand the interaction between Openser and these external elements we can then more effectively diagnose these type of problems.
On 10/19/06, Mark Kent mark@noc.mainstreet.net wrote:
The two messages I read with the above subject seem to overlook some important concepts:
a) Like many many servers, openser is a high-level application. It depends on a complicated under-world of services and protocols. The operation of it depends on many external elements, all of which should be in good working order.
b) DNS resource records (RR) have time-to-live (TTL) attributes. Any application may cache RR up to the length of time specified by the TTL. When you restart something, you typically blow away the cache and start over. In general, most applications do not cache general name lookups, since that is a lower-level function. However, an application caching the hostname it's on and/or IP addresses to bind to is standard practice.
I have come to realise that it seems as though once loaded into memory and running, openser "caches" the config file and also does not appear to re-check for changes in network conditions
Yes, isn't that great! It shouldn't check until either told to by a human or when the underlying protocol indicates that it is time for a refresh (like a DNS TTL expiring).
Regarding this:
I had to lock-down the network card to 10mbit full-duplex. It was autoselecting 100mbit half-duplex. Hope that helps someone... sometime...
Autoselecting 100/half probably means that the link auto-negotiation failed, as that is the default. It might fail because the other side was nailed down, perhaps to 10/full. That seems like an unlikely choice... but one reason why it might be nailed at 10mbits is because someone before you couldn't get it to run well at 100mbits and discovered that setting it to 10 was a "solution." If that was the case, I'ld guess that the cable between the switch and the server is lengthy and that it was not tied down in the prescribed order (wO, O, wG, Bl, wBl, G, wBr, Br) [or swap O and G].
I apologize if this email comes across as a little snooty. This is my first email of the day and I often have trouble phrasing things in a nice way prior to my coffee kicking in.
-mark
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