Timeout issues - Suggestions / Solutions?
Mark_Andrews at isc.org
Mark_Andrews at isc.org
Fri May 24 01:03:56 UTC 2002
>
> In working to debug another problem with some others, I've noticed that I'm
> unable to do a MX query for Lycos.Com without it timing out. Upon trying to
> deliver mail to Lycos.com, it times out getting a MX record for Lycos.com
> and thus does a A record lookup for Lycos.Com. This ends up causing issues
> as the mailing list software tries to deliver e-mail to Lycos.com @
> 209.202.192.30 which is NOT a mail server.
>
> Each time I run my test, I restart named beforehand to flush the cache.
>
> In the example below, I had to extend the timeout to 20 seconds as the query
> took 19956 msec to complete. I did the same query with HotMail.Com and it
> took 493 msec.
>
>
> Any reason why it would take so long to receive a result from Lycos.com?
>
> Does it have to do with the query being too large for TCP and its switching
> to UDP?
>
> How can I check each Lycos NS to see if its a specific name server that is
> causing the timeout issue?
>
> What can be done to reduce the lookup time besides pre caching?
> Ask Lycos to reduce the size of their MX list?
>
>
>
> My Setup: RedHat 7.2, Bind 8.3.1, T1 with UUnet.
>
> - David
>
>
> dig -t mx +debug +d2 +time=20 lycos.com
>
> ; <<>> DiG 8.3 <<>> -t +debug +d2 +time=20 lycos.com
> ;; res_nmkquery(QUERY, lycos.com, IN, MX)
> ;; res options: init debug recurs defnam dnsrch ?0x80000000?
> ;; res_send()
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 23280
> ;; flags: rd; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
> ;; QUERY SECTION:
> ;; lycos.com, type = MX, class = IN
>
> ;; Querying server (# 1) address = 127.0.0.1
> ;; new DG socket
> ;; truncated answer
> ;; Querying server (# 1) address = 127.0.0.1
> ;; got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 23280
> ;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 5, ADDITIONAL: 20
> ;; QUERY SECTION:
> ;; lycos.com, type = MX, class = IN
>
> ;; ANSWER SECTION:
> lycos.com. 1H IN MX 10 mx4.mail.lycos.com.
> lycos.com. 1H IN MX 10 mx1.mail.lycos.com.
> lycos.com. 1H IN MX 10 mx2.mail.lycos.com.
> lycos.com. 1H IN MX 10 mx3.mail.lycos.com.
>
> ;; AUTHORITY SECTION:
> lycos.com. 1H IN NS ns1.hotwired.com.
> lycos.com. 1H IN NS ns2.hotwired.com.
> lycos.com. 1H IN NS ns3.hotwired.com.
> lycos.com. 1H IN NS ns4.hotwired.com.
> lycos.com. 1H IN NS ns5.hotwired.com.
>
> ;; ADDITIONAL SECTION:
> mx4.mail.lycos.com. 1H IN A 209.185.123.129
> mx4.mail.lycos.com. 1H IN A 209.185.123.151
> mx4.mail.lycos.com. 1H IN A 209.185.123.149
> mx4.mail.lycos.com. 1H IN A 209.185.123.126
> mx4.mail.lycos.com. 1H IN A 209.185.123.198
> mx4.mail.lycos.com. 1H IN A 209.185.123.123
> mx4.mail.lycos.com. 1H IN A 209.185.123.197
> mx2.mail.lycos.com. 1H IN A 209.185.123.148
> mx2.mail.lycos.com. 1H IN A 209.185.123.130
> mx2.mail.lycos.com. 1H IN A 209.185.123.152
> mx2.mail.lycos.com. 1H IN A 209.185.123.147
> mx3.mail.lycos.com. 1H IN A 209.185.123.124
> mx3.mail.lycos.com. 1H IN A 209.185.123.199
> mx3.mail.lycos.com. 1H IN A 209.185.123.127
> mx3.mail.lycos.com. 1H IN A 209.185.123.128
> ns1.hotwired.com. 1d23h59m40s IN A 209.202.224.253
> ns2.hotwired.com. 1d23h59m40s IN A 209.202.220.8
> ns3.hotwired.com. 1d23h59m40s IN A 209.202.228.10
> ns4.hotwired.com. 1d23h59m40s IN A 209.202.221.55
> ns5.hotwired.com. 1d23h59m40s IN A 209.202.193.252
>
> ;; Total query time: 19956 msec
> ;; FROM: CorpDNS to SERVER: default -- 127.0.0.1
> ;; WHEN: Thu May 23 15:23:38 2002
> ;; MSG SIZE sent: 27 rcvd: 531
>
>
>
> dig -t mx +debug +d2 +time=20 hotmail.com
>
> ; <<>> DiG 8.3 <<>> -t +debug +d2 +time=20 hotmail.com
> ;; res_nmkquery(QUERY, hotmail.com, IN, MX)
> ;; res options: init debug recurs defnam dnsrch ?0x80000000?
> ;; res_send()
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 22088
> ;; flags: rd; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
> ;; QUERY SECTION:
> ;; hotmail.com, type = MX, class = IN
>
> ;; Querying server (# 1) address = 127.0.0.1
> ;; new DG socket
> ;; got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 22088
> ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 14, AUTHORITY: 4, ADDITIONAL: 7
> ;; QUERY SECTION:
> ;; hotmail.com, type = MX, class = IN
>
> ;; ANSWER SECTION:
> hotmail.com. 1H IN MX 5 mx10.hotmail.com.
> hotmail.com. 1H IN MX 5 mx11.hotmail.com.
> hotmail.com. 1H IN MX 5 mx12.hotmail.com.
> hotmail.com. 1H IN MX 5 mx13.hotmail.com.
> hotmail.com. 1H IN MX 5 mx14.hotmail.com.
> hotmail.com. 1H IN MX 5 mx15.hotmail.com.
> hotmail.com. 1H IN MX 5 mx01.hotmail.com.
> hotmail.com. 1H IN MX 5 mx02.hotmail.com.
> hotmail.com. 1H IN MX 5 mx04.hotmail.com.
> hotmail.com. 1H IN MX 5 mx05.hotmail.com.
> hotmail.com. 1H IN MX 5 mx06.hotmail.com.
> hotmail.com. 1H IN MX 5 mx07.hotmail.com.
> hotmail.com. 1H IN MX 5 mx08.hotmail.com.
> hotmail.com. 1H IN MX 5 mx09.hotmail.com.
>
> ;; AUTHORITY SECTION:
> hotmail.com. 1H IN NS ns1.hotmail.com.
> hotmail.com. 1H IN NS ns2.hotmail.com.
> hotmail.com. 1H IN NS ns3.hotmail.com.
> hotmail.com. 1H IN NS ns4.hotmail.com.
>
> ;; ADDITIONAL SECTION:
> mx10.hotmail.com. 1H IN A 64.4.49.135
> mx11.hotmail.com. 1H IN A 64.4.49.199
> mx12.hotmail.com. 1H IN A 64.4.50.7
> mx13.hotmail.com. 1H IN A 64.4.50.71
> mx14.hotmail.com. 1H IN A 65.54.232.7
> mx15.hotmail.com. 1H IN A 65.54.232.71
> mx01.hotmail.com. 1H IN A 64.4.55.71
>
> ;; Total query time: 493 msec
> ;; FROM: CorpDNS to SERVER: default -- 127.0.0.1
> ;; WHEN: Thu May 23 16:05:12 2002
> ;; MSG SIZE sent: 29 rcvd: 507
I suspect that you have a firewall / nat that is not EDNS0
aware between you and the internet and it is swallowing /
corrupting the EDNS queries / responses.
You can request a EDNS query by specifying +dn.
Mark
; <<>> DiG 8.3 <<>> +dn mx lycos.com @ns4.hotwired.com +qr +ignoretc
; (1 server found)
;; res options: init igntc recurs defnam dnsrch dnssec
;; res_send()
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 16102
;; flags: rd; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; QUERY SECTION:
;; lycos.com, type = MX, class = IN
;; ADDITIONAL SECTION:
; EDNS: version: 0, udp=4096, flags=8000
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 16102
;; flags: qr aa rd; QUERY: 1, ANSWER: 4, AUTHORITY: 5, ADDITIONAL: 26
;; QUERY SECTION:
;; lycos.com, type = MX, class = IN
;; ANSWER SECTION:
lycos.com. 1H IN MX 10 mx3.mail.lycos.com.
lycos.com. 1H IN MX 10 mx4.mail.lycos.com.
lycos.com. 1H IN MX 10 mx1.mail.lycos.com.
lycos.com. 1H IN MX 10 mx2.mail.lycos.com.
;; AUTHORITY SECTION:
lycos.com. 1H IN NS ns1.hotwired.com.
lycos.com. 1H IN NS ns2.hotwired.com.
lycos.com. 1H IN NS ns3.hotwired.com.
lycos.com. 1H IN NS ns4.hotwired.com.
lycos.com. 1H IN NS ns5.hotwired.com.
;; ADDITIONAL SECTION:
mx3.mail.lycos.com. 1H IN A 209.185.123.124
mx3.mail.lycos.com. 1H IN A 209.185.123.199
mx3.mail.lycos.com. 1H IN A 209.185.123.127
mx3.mail.lycos.com. 1H IN A 209.185.123.128
mx4.mail.lycos.com. 1H IN A 209.185.123.129
mx4.mail.lycos.com. 1H IN A 209.185.123.151
mx4.mail.lycos.com. 1H IN A 209.185.123.149
mx4.mail.lycos.com. 1H IN A 209.185.123.126
mx4.mail.lycos.com. 1H IN A 209.185.123.198
mx4.mail.lycos.com. 1H IN A 209.185.123.123
mx4.mail.lycos.com. 1H IN A 209.185.123.197
mx1.mail.lycos.com. 1H IN A 209.185.123.196
mx1.mail.lycos.com. 1H IN A 209.185.123.153
mx1.mail.lycos.com. 1H IN A 209.185.123.125
mx1.mail.lycos.com. 1H IN A 209.185.123.132
mx1.mail.lycos.com. 1H IN A 209.185.123.131
mx2.mail.lycos.com. 1H IN A 209.185.123.148
mx2.mail.lycos.com. 1H IN A 209.185.123.130
mx2.mail.lycos.com. 1H IN A 209.185.123.152
mx2.mail.lycos.com. 1H IN A 209.185.123.147
ns1.hotwired.com. 2H IN A 209.202.224.253
ns2.hotwired.com. 2H IN A 209.202.220.8
ns3.hotwired.com. 2H IN A 209.202.228.10
ns4.hotwired.com. 2H IN A 209.202.221.55
ns5.hotwired.com. 2H IN A 209.202.193.252
; EDNS: version: 0, udp=4096, flags=0000
;; Total query time: 286 msec
;; FROM: drugs.dv.isc.org to SERVER: ns4.hotwired.com 209.202.221.55
;; WHEN: Fri May 24 11:03:13 2002
;; MSG SIZE sent: 38 rcvd: 622
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: Mark.Andrews at isc.org
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