Debug.pfftpproxy=1 to enable LAN to WAN FTP

athurdent

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

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

@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

@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

@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

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

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

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

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

jimp

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

jlzentveld

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

athurdent

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

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--

Wait for snapshots of tomorrow and test.

athurdent

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

@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.

doktornotor

@lucky:

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

I had no issues before the latest patches. Broke more than it fixed.

athurdent

My issues with FTP began after:
https://redmine.pfsense.org/issues/2650#note-9
Would be great if those patches could be reverted. FTP is sluggish/broken on both of my WAN lines now.

gogol

I am on "built on Fri Jul 12 10:55:43 EDT 2013" but I still have problems when the proxy is enabled (default value).

doktornotor

On another note, I still managed to get kernel panic with FTP traffic with

2.1-RC0 (i386) built on Thu Jul 11 23:06:42 EDT 2013 FreeBSD 8.3-RELEASE-p8

The more patches here go in, the more broken the thing is, and I have yet to see anyone reporting any improvement to the issues they were supposed to be fixed. Please, revert the stuff altogether.