nanog mailing list archives
Re: Common operational misconceptions
From: Daniel Griggs <daniel () fx net nz>
Date: Fri, 17 Feb 2012 10:23:30 +1300
Seems like dig doesn't always advertise a big enough buffer, I was having the same issue as you. If you set the buffer size on the command line it works as directed. Daniels-Mac-mini:~ daniel$ dig edns-v4-ok.isc.org txt @149.20.64.58 ;; Truncated, retrying in TCP mode. ;; Connection to 149.20.64.58#53(149.20.64.58) for edns-v4-ok.isc.orgfailed: connection refused. Daniels-Mac-mini:~ daniel$ dig edns-v4-ok.isc.org txt @149.20.64.58+bufsize=4096 ; <<>> DiG 9.7.3-P3 <<>> edns-v4-ok.isc.org txt @149.20.64.58 +bufsize=4096 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 18209 ;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1 ;; WARNING: recursion requested but not available ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;edns-v4-ok.isc.org. IN TXT ;; ANSWER SECTION: edns-v4-ok.isc.org. 0 IN TXT "EDNS-4096-OK" "EDNS-4096-OK" "EDNS-4096-OK" "EDNS-4096-OK" "EDNS-4096-OK" "EDNS-4096-OK" <snip> "EDNS-4" ;; Query time: 176 msec ;; SERVER: 149.20.64.58#53(149.20.64.58) ;; WHEN: Fri Feb 17 10:22:08 2012 ;; MSG SIZE rcvd: 4096 On 17 February 2012 05:53, Phil Regnauld <regnauld () nsrc org> wrote:
Borderline dns-ops, sorry folks! - but this is interesting as we've been talking about ipv6 being operational, and this is part of it... Mark Andrews (marka) writes:If you are seeing TC between the resolver and the server and the TCPquery is being answers thensomething in the path is intercepting the DNS queries.TC is on the answer from the remote server to my resolver, so yeah, seems like something is messing with the packets.Don't see any v6 fragments (that'd be a problem since PF doesn'thandlethem on this host).You should see something like this on the wire. The second query is toanswerdig's query over TCP.I'm not seeing fragments as you are. Here's what I see: 14:40:20.955876 IP6 2001:2000:1080:d::2.64561 > 2001:4f8:0:2::8.53: 52841 TXT? edns-v6-ok.isc.org. (36) 14:40:21.141948 IP6 2001:4f8:0:2::8.53 > 2001:2000:1080:d::2.64561: 52841*-| 0/0/0 (36) 14:40:21.142259 IP6 2001:2000:1080:d::2.53262 > 2001:4f8:0:2::8.53: Flags [S], seq 1112939462, win 65535, options [mss 1440,nop,wscale 6,sackOK,TS val 2571957531 ecr 0], length 0 14:40:21.327895 IP6 2001:4f8:0:2::8.53 > 2001:2000:1080:d::2.53262: Flags [R.], seq 0, ack 1112939463, win 0, length 0 Cheers, Phil
-- Daniel Griggs Network Operations e: daniel () fx net nz d: +64 4 4989567
Current thread:
- Re: Common operational misconceptions, (continued)
- Re: Common operational misconceptions Masataka Ohta (Feb 15)
- Re: Common operational misconceptions Steve Bertrand (Feb 15)
- Re: Common operational misconceptions sthaug (Feb 16)
- Re: Common operational misconceptions Mark Andrews (Feb 16)
- Re: Common operational misconceptions Jeroen Massar (Feb 16)
- Re: Common operational misconceptions Mark Andrews (Feb 16)
- Re: Common operational misconceptions Phil Regnauld (Feb 16)
- Re: Common operational misconceptions Mark Andrews (Feb 16)
- Re: Common operational misconceptions Phil Regnauld (Feb 16)
- Re: Common operational misconceptions Mark Andrews (Feb 16)
- Re: Common operational misconceptions Daniel Griggs (Feb 16)
- Re: Common operational misconceptions Mark Andrews (Feb 16)
- Re: Common operational misconceptions Owen DeLong (Feb 15)
- Re: Common operational misconceptions Paul Thornton (Feb 16)
- Re: Common operational misconceptions Jared Mauch (Feb 16)
- Re: Common operational misconceptions Owen DeLong (Feb 16)
- Re: Common operational misconceptions Ray Soucy (Feb 16)
- Re: Common operational misconceptions Jeff Kell (Feb 16)
- Re: Common operational misconceptions Chuck Anderson (Feb 16)
- Re: Common operational misconceptions Jack Bates (Feb 16)
- Re: Common operational misconceptions Carsten Bormann (Feb 16)