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Thread: Slow initial response
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06-07-2005, 05:40 PM #1Junior Guru Wannabe
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Slow initial response
On my server, whenever I connect to something for the first time, it's very slow, all the following requests go on fine.
For example, if I try access a website, for the first time, the browser hangs for a bit, and then the page loads really fast. All the following page requests go really fast as well. I am able to download at over 200kb/sec (my isp limit)
When I try to send an email thru the server (via outlook express), OE just hangs for a bit and then sends the email real quick.
FTP is the same story, but here I can actuall see at what spots it is hanging. First it hangs at "Resolving host name" for a bit, then it hangs a lot more at "Socket connected waiting for login sequence.". The second part seems to happen every time I connect. And again, the transfers are really fast.
What do you think could be the problem?
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06-07-2005, 06:01 PM #2Web Hosting Master
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Re: Slow initial response
Originally posted by moltar
FTP is the same story, but here I can actuall see at what spots it is hanging. First it hangs at "Resolving host name" for a bit, then it hangs a lot more at "Socket connected waiting for login sequence.". The second part seems to happen every time I connect. And again, the transfers are really fast.
What do you think could be the problem?
If there is a DNS server already setup, make sure the server is performing forward- and reverse-lookups properly from the server. Try to resolve the hostname of you PC from the server and try to resolve the IP address; e.g.,
dig @dns.ser.ver.ip A blah.hostname.com
dig @dns.ser.ver.ip PTR 1.0.168.192.in-addr.arpa
My other guess is your host accessing this server is not reverse-resolving (i.e., w.x.y.z IP address of your PC's host does not resolve to a fully-qualified host name).
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06-07-2005, 06:01 PM #3Junior Guru Wannabe
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Kernel: Linux 2.6.10-1.771_FC2 #1 Mon Mar 28 00:50:14 EST 2005 i686 athlon i386 GNU/Linux
CP: Plesk 7.5.2
Distro: FC2
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06-07-2005, 06:19 PM #4Junior Guru Wannabe
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This is the output of the commands you suggested. Everything seems to be find. And my IP does resolve. This does not happen with other sites usually. Only with my server.
Note: the values were faked.
Code:Script started on Tue 07 Jun 2005 06:07:03 PM EDT [root@localhost root]# cat /etc/resolv.conf nameserver 69.64.44.50 [root@hunox root]# dig @69.64.44.50 A CPE000c41490777-CM014170000000.cpe.net.cable.rogers.com ; <<>> DiG 9.2.3 <<>> @69.64.44.50 A CPE000c41490777-CM014170000000.cpe.net.cable.rogers.com ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 17959 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 4 ;; QUESTION SECTION: ;CPE000c41490777-CM014170000000.cpe.net.cable.rogers.com. IN A ;; ANSWER SECTION: CPE000c41490777-CM014170000000.cpe.net.cable.rogers.com. 874 IN A 24.212.49.205 ;; AUTHORITY SECTION: cpe.net.cable.rogers.com. 1454 IN NS ns2.wlfdle.rnc.net.cable.rogers.com. cpe.net.cable.rogers.com. 1454 IN NS ns1.ym.rnc.net.cable.rogers.com. cpe.net.cable.rogers.com. 1454 IN NS ns1.wlfdle.rnc.net.cable.rogers.com. cpe.net.cable.rogers.com. 1454 IN NS ns2.ym.rnc.net.cable.rogers.com. ;; ADDITIONAL SECTION: ns1.ym.rnc.net.cable.rogers.com. 164744 IN A 24.153.22.141 ns1.wlfdle.rnc.net.cable.rogers.com. 157474 IN A 24.153.22.13 ns2.ym.rnc.net.cable.rogers.com. 50088 IN A 24.153.22.142 ns2.wlfdle.rnc.net.cable.rogers.com. 39207 IN A 24.153.22.14 ;; Query time: 1 msec ;; SERVER: 69.64.44.50#53(69.64.44.50) ;; WHEN: Tue Jun 7 18:10:40 2005 ;; MSG SIZE rcvd: 239 [root@localhost root]# dig @69.64.44.50 PTR 205.49.212.24.in-addr.arpa ; <<>> DiG 9.2.3 <<>> @69.64.44.50 PTR 205.49.212.24.in-addr.arpa ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 41086 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 4 ;; QUESTION SECTION: ;205.49.212.24.in-addr.arpa. IN PTR ;; ANSWER SECTION: 205.49.212.24.in-addr.arpa. 1800 IN PTR CPE000c41490777-CM014170000000.cpe.net.cable.rogers.com. ;; AUTHORITY SECTION: 112.24.in-addr.arpa. 3270 IN NS ns1.ym.rnc.net.cable.rogers.com. 112.24.in-addr.arpa. 3270 IN NS ns1.wlfdle.rnc.net.cable.rogers.com. 112.24.in-addr.arpa. 3270 IN NS ns2.ym.rnc.net.cable.rogers.com. 112.24.in-addr.arpa. 3270 IN NS ns2.wlfdle.rnc.net.cable.rogers.com. ;; ADDITIONAL SECTION: ns1.ym.rnc.net.cable.rogers.com. 164603 IN A 24.153.22.141 ns1.wlfdle.rnc.net.cable.rogers.com. 157333 IN A 24.153.22.13 ns2.ym.rnc.net.cable.rogers.com. 49947 IN A 24.153.22.142 ns2.wlfdle.rnc.net.cable.rogers.com. 39066 IN A 24.153.22.14 ;; Query time: 45 msec ;; SERVER: 69.64.44.50#53(69.64.44.50) ;; WHEN: Tue Jun 7 18:13:01 2005 ;; MSG SIZE rcvd: 263 [root@localhost root]# exit Script done on Tue 07 Jun 2005 06:13:14 PM EDT
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06-07-2005, 06:20 PM #5I Squash Server Problems
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Well I am not sure why the web site would be slow unless some code or the server is having to do DNS lookups.
Some ftp servers (proftpd for example), may try to do reverse DNS lookups. This is true with some email services. If your IP does not have reverse DNS, then you have to wait for the lookup to timeout before continuing. This is best resolved by assuring that your server has proper DNS configured and that services such as FTP/Apache/POP3/IMAP do not require reverse DNS lookups.
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06-07-2005, 06:30 PM #6WHT Addict
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Plesk Ident Problem
Check to make sure that the name servers that are used for reverse resolution have not been shut down or are working properly. These name servers are specified within the /etc/resolv.conf file and can be replaced if need be.
It's also very possible that the name servers in the /etc/resolv.conf file are working fine but the ip from where the client is accessing the server is not reverse resolvable. In this case you could turn off the reverse lookup completely.
For Red Hat servers the -Rt0 option needs to be added to the beginning of the server_args line in the /etc/xinetd.d/smtp_psa file:
server_args = -Rt0 /var/qmail/bin/relaylock......
It is necessary to restart xinetd since the changes will take effect the next time SMTP is used.
The wrapper /var/qmail/bin/tcp-env that plesk uses in front of qmail is sending an ident (port 113) request back to the host originating the connection. If the originating host is running a firewall which drops packets instead of sending rejects, tcp-env waits 25 seconds for a response before timing out. The new Windows Firewall which ships with Windows XP SP2 behaves this You can tell tcp-env to stop waiting for ident responses by adding the -R parameter to it's server_args in /etc/xinetd.d/smtp_psa, like this:
server = /var/qmail/bin/tcp-env
server_args = -R /var/qmail/bin/relaylock ....
For FTP be sure you have these OFF in proftpd.conf
IdentLookups off
UseReverseDNS off
Hope this helps.knowledge is Power , Spread it.
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ahmed@e-tutankhamun.com
AIM:AhmedFouad0 , yahooID:xor2004
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06-07-2005, 06:31 PM #7Junior Guru Wannabe
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the IP on my machine has a proper DNS entry. It resolves very fast. I don't think it's related to my IP. I should test from other ISPs.
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06-07-2005, 06:44 PM #8Junior Guru Wannabe
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AhmedFouad, Thanks for your help!
Both suggestions worked! The first one with -Rt0 was listed in FAQ from my ISP. I tried it before, but it for some reason didn't work. Now I think about it, I think I didnt restart the xinetd. But it worked like magic now!
FTP also worked. Those two lines were not "on", but they were not listed in config file at all. I guess they are turned on by default. I added those two lines, restarted xinetd and it also worked like magic.
Now the only problem is apache. It's not happening all the time, so it's really hard to track this one.
Thanks for all your help!
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06-07-2005, 06:53 PM #9WHT Addict
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Well for Apache it's only one directive that can cause this delay
but I think it's OFF by default in cPanel , Plesk , DA
Make sure you have HostnameLookups Off
in httpd.conf
Glad to see the other services got fixed.knowledge is Power , Spread it.
www.e-tutankhamun.com
ahmed@e-tutankhamun.com
AIM:AhmedFouad0 , yahooID:xor2004
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06-07-2005, 07:03 PM #10Web Hosting Master
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i just started reading this but see you got it resolved good to see all things go
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06-07-2005, 07:32 PM #11Junior Guru Wannabe
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HostnameLookups was set to off. As i said, this doesn't happen all the time, that's the strange thing. And it doesn't seem to happen for all domains. Some are fine, and some of them take a while...