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Groups > comp.os.linux.networking > #4194
| From | T <T@invalid.invalid> |
|---|---|
| Newsgroups | comp.os.linux.networking |
| Subject | Re: Need help with iptables and ftp |
| Date | 2018-08-26 17:11 -0700 |
| Organization | A noiseless patient Spider |
| Message-ID | <plvfkh$qj5$1@dont-email.me> (permalink) |
| References | (1 earlier) <slrnpo20v9.31ka.grahn+nntp@frailea.sa.invalid> <pltgel$qaa$1@dont-email.me> <plts91$2k58$1@saria.nerim.net> <plv4mb$ft6$1@dont-email.me> <plvf39$add$1@dont-email.me> |
On 08/26/2018 05:02 PM, William Unruh wrote: > On 2018-08-26, T <T@invalid.invalid> wrote: >> On 08/26/2018 02:35 AM, Pascal Hambourg wrote: >>> Le 26/08/2018 à 08:13, T a écrit : >>>> >>>> Here are my notes: >>> >>> And here are my comments. >>> >>>> How to track ftp's high port with Fedora and iptables: >>>> >>>> Problem: iptables will not automatically track ftp's high ports >>>> (firewalld will). >>> >>> Iptables does not track anything by itself. Netfilter's connection >>> tracking aka "conntrack" does. Iptables just uses the resulting state. >>> >>> There are no such "FTP high ports", >> >> http://slacksite.com/other/ftp.html#passive >> From the server-side firewall's standpoint, to support passive mode >> >> FTP the following communication channels need to be opened: >> FTP server's port 21 from anywhere (Client initiates connection) >> FTP server's port 21 to ports > 1023 (Server responds to client's >> control port) >> FTP server's ports > 1023 from anywhere (Client initiates data >> connection to random port specified by server) >> FTP server's ports > 1023 to remote ports > 1023 (Server sends ACKs >> (and data) to client's data port) >> >> Basically, after the connection is established, communications in >> passive mode switches to all high ports. > > Yes. So? The original connection is made on port 21. > I am not sure why you would want iptables to control those "high ports"? > If you disallow port 21, ftp cannot get started. > And there is abosolutely no way, unless it reads the inside of the > packets, and even there there is not much info, for iptables to know > this is ftp rather than something else. 21 is allowed. I have to track these high ports as in passive mode the server will send you a SYN on a high port and after that you only communicate on high ports. > >> >> This is a pain in the ass to track, so nf_conntrack_ftp was >> created > > What is it you want to track? And why? Take a look here. This is a passive mode ftp connection that got bounced before I got my rules straight kernel: dsl-out Everything Else IN= OUT=eno2 SRC=192.168.xxx.yyy DST=208.106.xxx.yyy LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=25991 DF PROTO=TCP SPT=59698 DPT=21023 WINDOW=29200 RES=0x00 SYN URGP=0 Source port SPT=59698 Destination port DPT=21023 All high ports. That is why you need nf_conntrack_ftp which keeps track of them for you. Note that it is a SYN packet
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Need help with iptables and ftp T <T@invalid.invalid> - 2018-08-24 15:39 -0700
Re: Need help with iptables and ftp T <T@invalid.invalid> - 2018-08-24 16:11 -0700
Re: Need help with iptables and ftp Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-08-25 07:23 +0000
Re: Need help with iptables and ftp T <T@invalid.invalid> - 2018-08-25 23:13 -0700
Re: Need help with iptables and ftp Pascal Hambourg <pascal@plouf.fr.eu.org> - 2018-08-26 11:35 +0200
Re: Need help with iptables and ftp T <T@invalid.invalid> - 2018-08-26 14:05 -0700
Re: Need help with iptables and ftp William Unruh <unruh@invalid.ca> - 2018-08-27 00:02 +0000
Re: Need help with iptables and ftp T <T@invalid.invalid> - 2018-08-26 17:11 -0700
Re: Need help with iptables and ftp William Unruh <unruh@invalid.ca> - 2018-08-27 02:00 +0000
Re: Need help with iptables and ftp T <T@invalid.invalid> - 2018-08-26 19:37 -0700
Re: Need help with iptables and ftp "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2018-08-26 22:59 -0400
Re: Need help with iptables and ftp T <T@invalid.invalid> - 2018-08-26 20:42 -0700
Re: Need help with iptables and ftp "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2018-08-27 00:29 -0400
Re: Need help with iptables and ftp T <T@invalid.invalid> - 2018-08-26 22:06 -0700
Re: Need help with iptables and ftp William Unruh <unruh@invalid.ca> - 2018-08-27 09:47 +0000
Re: Need help with iptables and ftp Pascal Hambourg <pascal@plouf.fr.eu.org> - 2018-09-03 20:47 +0200
Re: Need help with iptables and ftp William Unruh <unruh@invalid.ca> - 2018-08-27 09:44 +0000
Re: Need help with iptables and ftp "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2018-08-27 06:17 -0400
Re: Need help with iptables and ftp T <T@invalid.invalid> - 2018-08-27 12:21 -0700
Re: Need help with iptables and ftp Pascal Hambourg <pascal@plouf.fr.eu.org> - 2018-09-03 20:55 +0200
Re: Need help with iptables and ftp Scott Hemphill <hemphill@hemphills.net> - 2018-08-27 11:22 -0400
Re: Need help with iptables and ftp T <T@invalid.invalid> - 2018-08-27 12:18 -0700
Re: Need help with iptables and ftp T <T@invalid.invalid> - 2018-08-26 17:44 -0700
Re: Need help with iptables and ftp T <T@invalid.invalid> - 2018-08-26 17:43 -0700
Re: Need help with iptables and ftp Dan Purgert <dan@djph.net> - 2018-08-28 11:28 +0000
Re: Need help with iptables and ftp Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-08-29 05:38 +0000
Re: Need help with iptables and ftp Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2018-08-29 10:13 +0300
Re: Need help with iptables and ftp Dan Purgert <dan@djph.net> - 2018-08-29 09:52 +0000
Re: Need help with iptables and ftp William Unruh <unruh@invalid.ca> - 2018-08-29 12:13 +0000
Re: Need help with iptables and ftp Dan Purgert <dan@djph.net> - 2018-08-29 12:27 +0000
Re: Need help with iptables and ftp "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2018-08-29 11:14 -0400
Re: Need help with iptables and ftp Aragorn <thorongil@telenet.be> - 2018-08-29 23:15 +0200
Re: Need help with iptables and ftp Wouter Verhelst <w@uter.be> - 2018-08-30 10:35 +0200
Re: Need help with iptables and ftp Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-08-30 13:16 +0000
Re: Need help with iptables and ftp Richard Kettlewell <invalid@invalid.invalid> - 2018-08-30 16:15 +0100
Re: Need help with iptables and ftp Wouter Verhelst <w@uter.be> - 2018-08-30 18:42 +0200
Re: Need help with iptables and ftp William Unruh <unruh@invalid.ca> - 2018-08-31 00:31 +0000
Re: Need help with iptables and ftp Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-08-31 05:49 +0000
Re: Need help with iptables and ftp Wouter Verhelst <w@uter.be> - 2018-08-31 12:48 +0200
Re: Need help with iptables and ftp William Unruh <unruh@invalid.ca> - 2018-08-31 22:11 +0000
Re: Need help with iptables and ftp Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2018-09-01 09:56 +0300
Re: Need help with iptables and ftp Pascal Hambourg <pascal@plouf.fr.eu.org> - 2018-09-01 16:14 +0200
Re: Need help with iptables and ftp Wouter Verhelst <w@uter.be> - 2018-09-04 18:00 +0200
Re: Need help with iptables and ftp Pascal Hambourg <pascal@plouf.fr.eu.org> - 2018-09-04 20:36 +0200
Re: Need help with iptables and ftp Wouter Verhelst <w@uter.be> - 2018-09-05 10:25 +0200
Re: Need help with iptables and ftp Pascal Hambourg <pascal@plouf.fr.eu.org> - 2018-09-05 20:30 +0200
Re: Need help with iptables and ftp Wouter Verhelst <w@uter.be> - 2018-09-06 00:03 +0200
Re: Need help with iptables and ftp Pascal Hambourg <pascal@plouf.fr.eu.org> - 2018-09-01 15:56 +0200
Re: Need help with iptables and ftp William Unruh <unruh@invalid.ca> - 2018-09-01 19:18 +0000
Re: Need help with iptables and ftp Wouter Verhelst <w@uter.be> - 2018-09-04 18:01 +0200
Re: Need help with iptables and ftp William Unruh <unruh@invalid.ca> - 2018-08-31 00:25 +0000
Re: Need help with iptables and ftp "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2018-08-30 20:34 -0400
Re: Need help with iptables and ftp Dan Purgert <dan@djph.net> - 2018-08-31 09:25 +0000
Re: Need help with iptables and ftp Wouter Verhelst <w@uter.be> - 2018-08-31 12:50 +0200
Re: Need help with iptables and ftp Dan Purgert <dan@djph.net> - 2018-08-31 11:13 +0000
Re: Need help with iptables and ftp Allodoxaphobia <knock_yourself_out@example.net> - 2018-08-31 12:30 +0000
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