Vopros k MAN

[Гость]

1.nomer maximal'no vozmoznogo porta?

2.kakovo znachenie minimal'nogo(!) MSS (maximum segment size for TCP) v Linuxe?

3. gde v linuxe propisani razmeri: int, long, float?

[Гость]

Блин Ману будет трудно...

А ты сам то ответы знаешь?

(наверно проверка на программиста )

[Гость]

privet, malyata.

shshsh. eto ya tak, k s_lovu.

podvodim itogi lotterei:

1. man propal.

2. nikto za a ne zastupilsya

3. pora mne shto-to delat' poka menya tut ne zatravili.

itak, otvet na pervii vopros:

(obichno, po-krainei mere v ipv4 UDP/TCP headerah ) pod nomer porta otvoditsya ... 16bit.

eto znachit shto maximal'no vozmoznii port = 2^16, s uchetom nulya daet # 65535

otvet na tretii vopros:

kak i v normal'noi BSD: /usr/include/limits.h

odna "nepriyatnaya" cherta: ssilki na bits/xopen_lim.h i bits/posix*_lim.h

vot takoi, bardak:)

v NetBSD, naprimer, vse krasivo i kratko:)

nu eto, delo vkusa. nekotorie lyubyat pisat' zerez zopu.

ta ze bardachnaya bodyaga s O_ flagami v open() (2).

otvet na vtoroi vopros:

esli chestno, ya ozidal nachalo discussii.

vopros, priznayus', ne moi.

ne dayt mne pokoya lavri Darren Reed(a)

otez ipfilter(a), nedavno vistupil v bugtraqe na temu minimum MSS i potenzial'noi vozmoznosti DoS.

kayus', sam ne proveryal. Dareen skazal shto v linuxe 2.4

minimum mss = 88, v NT = 1 (!!!!!).

esli kto-to brosit v menya kamen', obeschayu proverit' minimum MSS samostoyatel'no.

ssilka na pervoistochnik:

http://securityfocus.com/cgi-bin/archive.pl?id=1&start=2001-11-20&end=2001-11-26&threads=1&tid=197928

privet, u.

[Гость]

Dareen prav,

kernel_src/4.xx/linux/include/net/tcp.h soderzit:

270

271 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */

272 #define TCP_MIN_MSS 88U

273