Debug.pfftpproxy=1 to enable LAN to WAN FTP

eri-- · Jul 4, 2013, 7:02 AM

Can you please be more specific on what does not work?

gogol · Jul 4, 2013, 7:47 AM

@ermal:

Can you please be more specific on what does not work?

You have got a PM

athurdent · Jul 4, 2013, 9:28 AM

@ermal:

Can you please be more specific on what does not work?

How to reproduce:
Just setup a fresh pfSense install, plug one (Win 7) device behind it and open a freshly installed Firefox. Key in

ftp://dd-wrt.com/others/eko/BrainSlayer-V24-preSP2/2013/05-27-2013-r21676/

and wait for "425 Failed to estabilsh connection".

doktornotor · Jul 4, 2013, 9:49 AM

@athurdent:

How to reproduce:
Just setup a fresh pfSense install, plug one (Win 7) device behind it and open a freshly installed Firefox. Key in
ftp://dd-wrt.com/others/eko/BrainSlayer-V24-preSP2/2013/05-27-2013-r21676/
and wait for "425 Failed to estabilsh connection".

This works perfectly fine with SpeedCommander, Total Commander and FlashFXP (both active and passive mode). Sorry, but FF is braindead FTP "client".

Active:


Connect to: (04.07.2013 11:53:54)
hostname=dd-wrt.com
username=anonymous
startdir=/others/eko/BrainSlayer-V24-preSP2/2013/05-27-2013-r21676/
dd-wrt.com=83.141.4.210
220 Welcome to DD-WRT FTP service.
USER anonymous
331 Please specify the password.
PASS ***********
230 Login successful.
SYST
215 UNIX Type: L8
FEAT
211-Features:
 EPRT
 EPSV
 MDTM
 PASV
 REST STREAM
 SIZE
 TVFS
 UTF8
211 End
HELP SITE
214-The following commands are recognized.
 ABOR ACCT ALLO APPE CDUP CWD  DELE EPRT EPSV FEAT HELP LIST MDTM MKD
 MODE NLST NOOP OPTS PASS PASV PORT PWD  QUIT REIN REST RETR RMD  RNFR
 RNTO SITE SIZE SMNT STAT STOR STOU STRU SYST TYPE USER XCUP XCWD XMKD
 XPWD XRMD
214 Help OK.
OPTS UTF8 ON
200 Always in UTF8 mode.
CWD /others/eko/BrainSlayer-V24-preSP2/2013/05-27-2013-r21676/
250 Directory successfully changed.
Connect ok!
PWD
257 "/others/eko/BrainSlayer-V24-preSP2/2013/05-27-2013-r21676"
Get directory
TYPE A
200 Switching to ASCII mode.
PORT 10,0,0,1,222,174
200 PORT command successful. Consider using PASV.
LIST
150 Here comes the directory listing.
Download
Waiting for server...
226 Directory send OK.

Passive:


Connect to: (04.07.2013 11:54:32)
hostname=dd-wrt.com
username=anonymous
startdir=/others/eko/BrainSlayer-V24-preSP2/2013/05-27-2013-r21676/
dd-wrt.com=83.141.4.210
220 Welcome to DD-WRT FTP service.
USER anonymous
331 Please specify the password.
PASS ***********
230 Login successful.
SYST
215 UNIX Type: L8
FEAT
211-Features:
 EPRT
 EPSV
 MDTM
 PASV
 REST STREAM
 SIZE
 TVFS
 UTF8
211 End
HELP SITE
214-The following commands are recognized.
 ABOR ACCT ALLO APPE CDUP CWD  DELE EPRT EPSV FEAT HELP LIST MDTM MKD
 MODE NLST NOOP OPTS PASS PASV PORT PWD  QUIT REIN REST RETR RMD  RNFR
 RNTO SITE SIZE SMNT STAT STOR STOU STRU SYST TYPE USER XCUP XCWD XMKD
 XPWD XRMD
214 Help OK.
OPTS UTF8 ON
200 Always in UTF8 mode.
CWD /others/eko/BrainSlayer-V24-preSP2/2013/05-27-2013-r21676/
250 Directory successfully changed.
Connect ok!
PWD
257 "/others/eko/BrainSlayer-V24-preSP2/2013/05-27-2013-r21676"
Get directory
TYPE A
200 Switching to ASCII mode.
PASV
227 Entering Passive Mode (83,141,4,210,241,176)
LIST
150 Here comes the directory listing.
Download
Waiting for server...
226 Directory send OK.

On that note, I must say pf/BSD does pretty impressive job here. Using active FTP from behind NAT has been just plain impossible with Linux/iptables-based firewalls.

athurdent · Jul 4, 2013, 10:11 AM

@doktornotor:

Sorry, but FF is braindead FTP "client".

Sure, but it used to work with Firefox. Plus it works behind all of the other Firewalls/Routers I have tested (Checkpoint, ASA, some D-Link device, DD-WRT, AVM Fritz…)
It's not only Firefox, Chrome does not work either.
I don't really care, but the average surfer/user will. So I posted a way how to reproduce the issue for debugging purposes.

doktornotor · Jul 4, 2013, 10:14 AM

Yeah, FF, Chrome, IE, Safari and any other mainsteam browser are all braindead FTP clients. I'd suggest to take your issue with the browser developers. As for debugging, no debugging is possible without a session transcript (as posted above) - good luck getting anything like that from the browser - or some wireshark sniffing.

athurdent · Jul 4, 2013, 10:15 AM

@doktornotor:

On that note, I must say pf/BSD does pretty impressive job here. Using active FTP from behind NAT has been just plain impossible with Linux/iptables-based firewalls.

modprobe ip_conntrack_ftp

;)

doktornotor · Jul 4, 2013, 10:16 AM

@athurdent:

modprobe ip_conntrack_ftp

;)

That does not really work (well or at all) with about half of FTP servers out there (a.k.a. waste of time).

athurdent · Jul 4, 2013, 11:27 AM

@doktornotor:

Yeah, FF, Chrome, IE, Safari and any other mainsteam browser are all braindead FTP clients. I'd suggest to take your issue with the browser developers. As for debugging, no debugging is possible without a session transcript (as posted above) - good luck getting anything like that from the browser - or some wireshark sniffing.

Well I already did put a lot of effort into debugging this problem if you look at post #11. If I find the time, I'll do that again with the lastest snapshots. For now I can only describe how to easily reproduce the issue for debugging purposes.

jimp · Jul 4, 2013, 1:45 PM

The easiest way to get a session capture from the firewall itself is this:

# pkg_add -r tcpflow
# rehash
# tcpflow -c -i em0 port 21

Get a capture from the LAN NIC, and the WAN NIC

ggzengel · Jul 4, 2013, 1:52 PM

Better to capture the whole traffic to the (otherwise unused) destination ip.
Because the traffic shouldn'd use port 21 (neither src and dst) for data and that's the problem.

jimp · Jul 4, 2013, 1:56 PM

It depends on which bit you're having an issue with.

tcpflow would show NAT/port translation errors a lot easier than digging through an entire capture. tcpflow prints out the plain text exchange between the client and server without having to dig through a binary capture; It gives you something you can just copy/paste as others have done earlier in this thread from FTP clients that actually work properly.

Getting all of the traffic to/from the target server would help find other issues (such as connections going to the wrong port).

ggzengel · Jul 4, 2013, 2:14 PM

But you don't see if server really connect from port 1234 to client port 2345 and the router expect this.

jimp · Jul 4, 2013, 2:19 PM

Yes, but as I said, a different problem entirely. They are both helpful but in different ways.

jlzentveld · Jul 5, 2013, 1:50 AM

I also had problems with ftp connections being very hit & miss since upgrading to 2.1. Setting this got it working again.

athurdent · Jul 5, 2013, 8:42 AM

I have setup a new pfSense VM on ESX 5.1 to debug this. I think I know what happened to my unresponisive ALIX test installation, pfSense just freezes after some time while trying to browse the FTP server stated some posts before. There's no error message, the console just freezes…
Any idea?

Edit: After 3 freezes while browsing the FTP my installation now crashed and rebooted. It collected the following attached crash report.

Edit2: I installed a fresh Snapshot from pfSense-LiveCD-2.1-RC0-amd64-20130701-1521.iso. I have tried everything but I was not able to freeze / crash it yet. Maybe the recent change to the FTP helper made pfSense somewhat unstable?

crash.txt

lucky · Jul 6, 2013, 4:04 PM

I started having issues on around the May 9th snapshot. I didn't notice it until this past week because my FTP server isn't used much. Setting debug.pfftpproxy=1 has restored services, for now.

My setup is fairly straightforward - three NICs, one WAN two LAN. The FTP server is in a VM that sits on one of the LAN segments. FTP server is a default Ubuntu wu-ftp daemon install. I have a NAT rule in place for FTP. I have traffic shaping, though FTP is not part of any special queue. That's about it. This has worked solidly until ~ May 9.

Note - When I was initially troubleshooting, I noticed that the firewall was denying SYN ACKs going from the FTP server back to the client. The client failed to properly FTP data to my server in both active and passive mode.

If I can provide anything else to help troubleshoot, please let me know and I'll get it for you.

eri-- · Jul 8, 2013, 12:55 PM

Wait for snapshots of tomorrow and test.

athurdent · Jul 9, 2013, 7:26 AM

FTP did not get any better with the lastest snapshot Mon Jul 8 21:53:11 EDT 2013 . It should contain the newest fixes according to```
cat /etc/version.lastcommit

Half of the time passive FTP works, but I am still seeing those in the logs when the passive FTP session hangs.
em0 is the LAN interface. My test system is single LAN/WAN.

Jul 9 08:51:02 pfsense-ipv6 pf: 00:00:14.413456 rule 4/0(match): block out on em0: (tos 0x0, ttl 53, id 24551, offset 0, flags [DF], proto TCP (6), length 52)
Jul 9 08:51:02 pfsense-ipv6 pf: 83.141.4.210.56941 > 192.168.x.x.56941: Flags [S.], cksum 0xa08a (correct), seq 1305586650, ack 72292906, win 5840, options [mss 1380,nop,nop,sackOK,nop,wscale 7], length 0

So the state table still does not get updated correctly by the FTP proxy/helper.
On the bright side, at least pfSense did not crash, yet.

Edit:
Active FTP does not work anymore, I'm getting those in the log:

Jul 9 09:25:29 pfsense-ipv6 pf: 83.141.4.210.21 > 192.168.x.x.49686: Flags [P.], cksum 0x966e (correct), ack 212331008, win 5840, length 51
Jul 9 09:25:29 pfsense-ipv6 pf: 00:00:00.212976 rule 4/0(match): block out on em0: (tos 0x0, ttl 53, id 9015, offset 0, flags [DF], proto TCP (6), length 91)
Jul 9 09:25:29 pfsense-ipv6 pf: 83.141.4.210.21 > 192.168.x.x.49686: Flags [P.], cksum 0x966e (correct), ack 212331008, win 5840, length 51
Jul 9 09:25:30 pfsense-ipv6 pf: 00:00:00.090747 rule 4/0(match): block out on em0: (tos 0x0, ttl 53, id 52027, offset 0, flags [DF], proto TCP (6), length 52)
Jul 9 09:25:30 pfsense-ipv6 pf: 83.141.4.210.21 > 192.168.x.x.49686: Flags [.], cksum 0x1e4e (correct), ack 212331009, win 5840, options [nop,nop,sack 1 {212330981:212331009}], length 0
Jul 9 09:25:30 pfsense-ipv6 pf: 00:00:00.335257 rule 4/0(match): block out on em0: (tos 0x0, ttl 53, id 23454, offset 0, flags [DF], proto TCP (6), length 91)
Jul 9 09:25:30 pfsense-ipv6 pf: 83.141.4.210.21 > 192.168.x.x.49686: Flags [P.], cksum 0x966d (correct), ack 212331009, win 5840, length 51
Jul 9 09:25:30 pfsense-ipv6 pf: 00:00:00.255013 rule 4/0(match): block out on em0: (tos 0x0, ttl 53, id 41021, offset 0, flags [DF], proto TCP (6), length 52)
Jul 9 09:25:30 pfsense-ipv6 pf: 83.141.4.210.21 > 192.168.x.x.49686: Flags [.], cksum 0x1e4d (correct), ack 212331009, win 5840, options [nop,nop,sack 1 {212330981:212331010}], length 0
Jul 9 09:25:31 pfsense-ipv6 pf: 00:00:00.597293 rule 4/0(match): block out on em0: (tos 0x0, ttl 53, id 24176, offset 0, flags [DF], proto TCP (6), length 91)
Jul 9 09:25:31 pfsense-ipv6 pf: 83.141.4.210.21 > 192.168.x.x.49686: Flags [P.], cksum 0x966d (correct), ack 212331009, win 5840, length 51
Jul 9 09:25:31 pfsense-ipv6 pf: 00:00:00.604381 rule 4/0(match): block out on em0: (tos 0x0, ttl 53, id 26446, offset 0, flags [DF], proto TCP (6), length 52)
Jul 9 09:25:31 pfsense-ipv6 pf: 83.141.4.210.21 > 192.168.x.x.49686: Flags [.], cksum 0x1e4d (correct), ack 212331009, win 5840, options [nop,nop,sack 1 {212330981:212331010}], length 0
Jul 9 09:25:32 pfsense-ipv6 pf: 00:00:01.101145 rule 4/0(match): block out on em0: (tos 0x0, ttl 53, id 11135, offset 0, flags [DF], proto TCP (6), length 91)
Jul 9 09:25:32 pfsense-ipv6 pf: 83.141.4.210.21 > 192.168.x.x.49686: Flags [P.], cksum 0x966d (correct), ack 212331009, win 5840, length 51
Jul 9 09:25:32 pfsense-ipv6 pf: 00:00:00.103532 rule 4/0(match): block out on em0: (tos 0x0, ttl 53, id 42482, offset 0, flags [DF], proto TCP (6), length 52)
Jul 9 09:25:32 pfsense-ipv6 pf: 83.141.4.210.21 > 192.168.x.x.49686: Flags [.], cksum 0x1e4d (correct), ack 212331009, win 5840, options [nop,nop,sack 1 {212330981:212331010}], length 0
Jul 9 09:25:34 pfsense-ipv6 pf: 00:00:01.204942 rule 4/0(match): block out on em0: (tos 0x0, ttl 53, id 64293, offset 0, flags [DF], proto TCP (6), length 52)
Jul 9 09:25:34 pfsense-ipv6 pf: 83.141.4.210.21 > 192.168.x.x.49686: Flags [.], cksum 0x1e4d (correct), ack 212331009, win 5840, options [nop,nop,sack 1 {212330981:212331010}], length 0

lucky · Jul 10, 2013, 2:44 PM

@ermal:

Wait for snapshots of tomorrow and test.

Still having the issue on: 2.1-RC0 (amd64) built on Tue Jul 9 23:33:36 EDT 2013

Update: just to clarify, setting debug.pfftpproxy=1 still makes connections to my FTP server work again.