Pristup na ftp.linux.cz

Petr Soucek petr na ryston.cz
Středa Květen 31 14:56:10 CEST 2000


David Rohleder wrote:
> 
> Vsechny servery z prvni skupiny pouzivaji wu-ftpd, servery z druhe
> skupiny pouzivaji ProFTPD
> 
> Mozna ma wu-ftp nejake problemy s MTU (zkusil bych treba MTU>=576)

Tim to nebude - u nas mame proftpd a k nam to taky neslo.

A navic to nefunguje obousmerne - zkousel jsem stahovat data z
test.tenez.cz a nekolikrat se mi stalo, ze se prenost zastavil na 3,15
MB a pokracoval az po 9 minutach.

Co tak treba verze kernelu?

Mam zaznam tcpdumpu jak tohoto spojeni, tak neuspesnych spojeni opacnym
smerem.

Vypada to tak, ze nejprve se ztrati jeden paket, nas server se snazi 16x
o obnovu TCP spojeni, ale nepodari se mu to bud vubec, nebo prvni
odpoved prijde az ta tech 9 minuut.

Tady je log celeho spojeni k nam z Tenezu:

09:04:22.504731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: S
584816532:584816532(0) win 32120 <mss 1460,sackOK,timestamp 111619876
0,nop,wscale 0> (DF)
nas server poslal zadost o navazani spojeni, tj SYN
09:04:22.724731 eth0 < test.tenez.cz.63825 > ns2.ryston.cz.ftp-data: S
219820032:219820032(0) ack 584816533 win 4096 <mss 1460>
vas server ji potvrdil, poslal SYN ACK
09:04:22.724731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
1:1(0) ack 1 win 32120 (DF)
a nas server potvrdil navazani spojeni ACK
09:04:22.754731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: P
1:1461(1460) ack 1 win 32120 (DF)
nas server posila prvnich 1460 byte (1-1461)
09:04:22.754731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: P
1461:2921(1460) ack 1 win 32120 (DF)
nas server posila dalsich 1460 byte (1461-2921)
09:04:22.964731 eth0 < test.tenez.cz.63825 > ns2.ryston.cz.ftp-data: .
1:1(0) ack 1 win 4096
vas server posle potvrzeni navazani spojeni ACK 1
a zaroven nastavuje prijimaci okno na 4096 byte - to je dost malo
09:04:25.754731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: P
1:1461(1460) ack 1 win 32120 (DF)
09:04:31.754731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: P
1:1461(1460) ack 1 win 32120 (DF)
09:04:43.754731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: P
1:1461(1460) ack 1 win 32120 (DF)
09:05:07.744731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: P
1:1461(1460) ack 1 win 32120 (DF)
09:05:55.744731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: P
1:1461(1460) ack 1 win 32120 (DF)
Tady nas server 5x znovu poslal prvnich 1460 B, protoze uz poslal 
vse, co se veslo do okna, a tam se vejdou jen dva pakety, a nedostal 
potvrzeni
09:05:55.874731 eth0 < test.tenez.cz.63825 > ns2.ryston.cz.ftp-data: .
1:1(0) ack 2921 win 4096
A tady najednou vas server potvrzuje prijeti tech druhych 1460 B
09:05:55.874731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: P
2921:4381(1460) ack 1 win 32120 (DF)
takze nas server posila tretich,
09:05:55.874731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
4381:5841(1460) ack 1 win 32120 (DF)
a ctvrtych 1460 bajtu
09:05:56.004731 eth0 < test.tenez.cz.63825 > ns2.ryston.cz.ftp-data: .
1:1(0) ack 4381 win 4096
tady vas server potvrdi prijeti tech tretich 1460 byte
09:05:56.014731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
5841:7301(1460) ack 1 win 32120 (DF)
a nas posila patych 1460 byte
09:05:56.844731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
4381:5841(1460) ack 1 win 32120 (DF)
09:05:58.784731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
4381:5841(1460) ack 1 win 32120 (DF)
a dvakrat opakuje poslani tech ctvrtych 1460 byte, prtoze na ne nema 
potvrzeni
09:05:58.904731 eth0 < test.tenez.cz.63825 > ns2.ryston.cz.ftp-data: .
1:1(0) ack 5841 win 4096
Konecne na tech ctvrtych 1460 byte prislo potvrzeni
09:05:58.914731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
5841:7301(1460) ack 1 win 32120 (DF)
09:06:02.784731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
5841:7301(1460) ack 1 win 32120 (DF)
09:06:10.544731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
5841:7301(1460) ack 1 win 32120 (DF)
09:06:26.064731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
5841:7301(1460) ack 1 win 32120 (DF)
09:06:57.104731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
5841:7301(1460) ack 1 win 32120 (DF)
09:07:59.184731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
5841:7301(1460) ack 1 win 32120 (DF)
09:09:59.174731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
5841:7301(1460) ack 1 win 32120 (DF)
09:11:59.164731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
5841:7301(1460) ack 1 win 32120 (DF)
09:13:59.164731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
5841:7301(1460) ack 1 win 32120 (DF)
09:15:59.154731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
5841:7301(1460) ack 1 win 32120 (DF)
09:17:59.154731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
5841:7301(1460) ack 1 win 32120 (DF)
09:19:59.144731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
5841:7301(1460) ack 1 win 32120 (DF)
09:21:59.144731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
5841:7301(1460) ack 1 win 32120 (DF)
09:23:59.134731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
5841:7301(1460) ack 1 win 32120 (DF)
09:25:59.124731 eth0 > ns2.ryston.cz.ftp-data > test.tenez.cz.63825: .
5841:7301(1460) ack 1 win 32120 (DF)
No a tady se snazil jeste 15x poslat ten paty 1460 b paket, ale uz ne 
nej nikdy nedostal potvrzeni.

Takze to je podrobny popis toho, jak to spojeni vypadalo a co se 
stalo - netisim ale, proc.

Nas pokus o prenos vypadal takto:

17:58:26.329827 193.85.145.231.3612 > ns2.ryston.cz.1271: P
415577:417025(1448) ack 0 win 16060 <nop,nop,timestamp 2068806 88892548>
(DF) [tos 0x8]

tady neprisel paket 417025:418473

17:58:26.399776 193.85.145.231.3612 > ns2.ryston.cz.1271: P
418473:419921(1448) ack 0 win 16060 <nop,nop,timestamp 2068813 88892553>
(DF) [tos 0x8]
17:58:26.399776 ns2.ryston.cz.1271 > 193.85.145.231.3612: . ack 417025
win 63712 <nop,nop,timestamp 88892569 2068806,nop,nop, sack 1
{418473:419921} > (DF)
17:58:26.419762 193.85.145.231.3612 > ns2.ryston.cz.1271: P
419921:421369(1448) ack 0 win 16060 <nop,nop,timestamp 2068813 88892553>
(DF) [tos 0x8]
17:58:26.419762 ns2.ryston.cz.1271 > 193.85.145.231.3612: . ack 417025
win 63712 <nop,nop,timestamp 88892571 2068806,nop,nop, sack 1
{418473:421369} > (DF)
17:58:26.449740 193.85.145.231.3612 > ns2.ryston.cz.1271: P
421369:422817(1448) ack 0 win 16060 <nop,nop,timestamp 2068813 88892553>
(DF) [tos 0x8]
17:58:26.449740 ns2.ryston.cz.1271 > 193.85.145.231.3612: . ack 417025
win 63712 <nop,nop,timestamp 88892574 2068806,nop,nop, sack 1
{418473:422817} > (DF)
17:58:26.539675 193.85.145.231.3612 > ns2.ryston.cz.1271: P
422817:424265(1448) ack 0 win 16060 <nop,nop,timestamp 2068827 88892569>
(DF) [tos 0x8]
17:58:26.539675 ns2.ryston.cz.1271 > 193.85.145.231.3612: . ack 417025
win 63712 <nop,nop,timestamp 88892583 2068806,nop,nop, sack 1
{418473:424265} > (DF)
17:58:26.559660 193.85.145.231.3612 > ns2.ryston.cz.1271: P
424265:425713(1448) ack 0 win 16060 <nop,nop,timestamp 2068827 88892569>
(DF) [tos 0x8]
17:58:26.559660 ns2.ryston.cz.1271 > 193.85.145.231.3612: . ack 417025
win 63712 <nop,nop,timestamp 88892585 2068806,nop,nop, sack 1
{418473:425713} > (DF)
17:58:26.589638 193.85.145.231.3612 > ns2.ryston.cz.1271: P
425713:427161(1448) ack 0 win 16060 <nop,nop,timestamp 2068827 88892569>
(DF) [tos 0x8]
17:58:26.589638 ns2.ryston.cz.1271 > 193.85.145.231.3612: . ack 417025
win 63712 <nop,nop,timestamp 88892588 2068806,nop,nop, sack 1
{418473:427161} > (DF)
17:58:26.609624 193.85.145.231.3612 > ns2.ryston.cz.1271: P
427161:428609(1448) ack 0 win 16060 <nop,nop,timestamp 2068830 88892571>
(DF) [tos 0x8]
17:58:26.609624 ns2.ryston.cz.1271 > 193.85.145.231.3612: . ack 417025
win 63712 <nop,nop,timestamp 88892590 2068806,nop,nop, sack 1
{418473:428609} > (DF)
17:58:26.709551 193.85.145.231.3612 > ns2.ryston.cz.1271: P
428609:430057(1448) ack 0 win 16060 <nop,nop,timestamp 2068844 88892583>
(DF) [tos 0x8]
17:58:26.709551 ns2.ryston.cz.1271 > 193.85.145.231.3612: . ack 417025
win 63712 <nop,nop,timestamp 88892600 2068806,nop,nop, sack 1
{418473:430057} > (DF)
17:58:26.739529 193.85.145.231.3612 > ns2.ryston.cz.1271: P
430057:431505(1448) ack 0 win 16060 <nop,nop,timestamp 2068845 88892585>
(DF) [tos 0x8]
17:58:26.739529 ns2.ryston.cz.1271 > 193.85.145.231.3612: . ack 417025
win 63712 <nop,nop,timestamp 88892603 2068806,nop,nop, sack 1
{418473:431505} > (DF)
17:58:26.759515 193.85.145.231.3612 > ns2.ryston.cz.1271: P
431505:432953(1448) ack 0 win 16060 <nop,nop,timestamp 2068848 88892588>
(DF) [tos 0x8]
17:58:26.759515 ns2.ryston.cz.1271 > 193.85.145.231.3612: . ack 417025
win 63712 <nop,nop,timestamp 88892605 2068806,nop,nop, sack 1
{418473:432953} > (DF)
17:58:26.779500 193.85.145.231.3612 > ns2.ryston.cz.1271: P
432953:434401(1448) ack 0 win 16060 <nop,nop,timestamp 2068850 88892590>
(DF) [tos 0x8]
17:58:26.779500 ns2.ryston.cz.1271 > 193.85.145.231.3612: . ack 417025
win 63712 <nop,nop,timestamp 88892608 2068806,nop,nop, sack 1
{418473:434401} > (DF)
17:58:26.859442 193.85.145.231.3612 > ns2.ryston.cz.1271: P
434401:435849(1448) ack 0 win 16060 <nop,nop,timestamp 2068859 88892600>
(DF) [tos 0x8]
17:58:26.859442 ns2.ryston.cz.1271 > 193.85.145.231.3612: . ack 417025
win 63712 <nop,nop,timestamp 88892615 2068806,nop,nop, sack 1
{418473:435849} > (DF)
17:58:26.879428 193.85.145.231.3612 > ns2.ryston.cz.1271: P
435849:437297(1448) ack 0 win 16060 <nop,nop,timestamp 2068861 88892603>
(DF) [tos 0x8]
17:58:26.879428 ns2.ryston.cz.1271 > 193.85.145.231.3612: . ack 417025
win 63712 <nop,nop,timestamp 88892618 2068806,nop,nop, sack 1
{418473:437297} > (DF)
17:58:26.909406 193.85.145.231.3612 > ns2.ryston.cz.1271: P
437297:438745(1448) ack 0 win 16060 <nop,nop,timestamp 2068863 88892605>
(DF) [tos 0x8]
17:58:26.909406 ns2.ryston.cz.1271 > 193.85.145.231.3612: . ack 417025
win 63712 <nop,nop,timestamp 88892620 2068806,nop,nop, sack 1
{418473:438745} > (DF)
17:58:26.929391 193.85.145.231.3612 > ns2.ryston.cz.1271: P
438745:440193(1448) ack 0 win 16060 <nop,nop,timestamp 2068866 88892608>
(DF) [tos 0x8]
17:58:26.929391 ns2.ryston.cz.1271 > 193.85.145.231.3612: . ack 417025
win 63712 <nop,nop,timestamp 88892622 2068806,nop,nop, sack 1
{418473:440193} > (DF)

Muj pocitac se porad dozaduje poslani toho chybejiciho paketu, ale 
marne.

17:58:52.670683 193.85.145.231.3601 > ns2.ryston.cz.4965: P
17806441:17807889(1448) ack 4189817416 win 16060 <nop,nop,timestamp
2071441 88865677> (DF) [tos 0x8]
17:58:52.670683 193.85.145.231.ftp > ns2.ryston.cz.4959: P
4222269275:4222269319(44) ack 4101865726 win 16060 <nop,nop,timestamp
2071441 88865697> (DF) [tos 0x10]
17:58:52.670683 193.85.145.231.ftp > ns2.ryston.cz.4959: FP 44:81(37)
ack 1 win 16060 <nop,nop,timestamp 2071441 88865697> (DF) [tos 0x10]
17:58:52.670683 ns2.ryston.cz.4965 > 193.85.145.231.3601: R
4189817416:4189817416(0) win 0 [tos 0x8]
17:58:52.670683 ns2.ryston.cz.4959 > 193.85.145.231.ftp: R
4101865726:4101865726(0) win 0 [tos 0x10]
17:58:52.670683 ns2.ryston.cz.4959 > 193.85.145.231.ftp: R
4101865726:4101865726(0) win 0 [tos 0x10]

A tady konecne na tu zadost vas server odpovi, ale po 9 minutach!!

18:07:45.608438 193.85.145.231.3612 > ns2.ryston.cz.1271: P
417025:418473(1448) ack 0 win 16060 <nop,nop,timestamp 2124761 88892622>
(DF) [tos 0x8]
18:07:45.608438 ns2.ryston.cz.1271 > 193.85.145.231.3612: . ack 440193
win 52128 <nop,nop,timestamp 88948494 2124761> (DF)
18:07:45.748335 193.85.145.231.3612 > ns2.ryston.cz.1271: P
440193:441641(1448) ack 0 win 16060 <nop,nop,timestamp 2124775 88948494>
(DF) [tos 0x8]

Petr Soucek


Další informace o konferenci Linux