Ports, rules, NAT
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Best thing to do would be to open your sniff in say wireshark so you can actually see what is getting sent back, or up the verbosity of the sniff. so you can see if your seeing syn, and then syn,ack back or just RST.
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indeed as i say you must have something on 192.168.1.35 or whatever is your web server ip blocking it/not accepting it for some reason
set this option and do a capture again -
I have nothing auto-updating, I have checked and rebooted most systems except PF at this point.
I do see 'some' logs in IIS about activesync, but nothing else gets back to the client or the web-browser in terms of webmail.
I predict it will be something silly and/or trivial, but it's not clearly obvious at this point.
I do really appreciate your help, but I dont understand wireshark or have it installed at this point.
Learning more about networking generically is on my list of to-do.
Just re-running that packet capture now...
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Does this help anyone?
16:27:43.348163 IP (tos 0x28, ttl 67, id 58574, offset 0, flags [DF], proto TCP (6), length 40)
138.201.87.102.42429 > 192.168.1.35.443: Flags [S], cksum 0xae6a (correct), seq 3568136006, win 29200, length 0
16:27:43.348722 IP (tos 0x0, ttl 128, id 14187, offset 0, flags [DF], proto TCP (6), length 44)
192.168.1.35.443 > 138.201.87.102.42429: Flags [S.], cksum 0x7a39 (correct), seq 1036996916, ack 3568136007, win 65392, options [mss 1460], length 0
16:27:43.388858 IP (tos 0x0, ttl 54, id 43753, offset 0, flags [none], proto TCP (6), length 40)
138.201.87.102.42429 > 192.168.1.35.443: Flags [R], cksum 0xe077 (correct), seq 3568136007, win 16384, length 0
16:27:44.407074 IP (tos 0x0, ttl 128, id 14188, offset 0, flags [DF], proto TCP (6), length 44)
192.168.1.35.443 > 138.201.87.102.34989: Flags [S.], cksum 0x3ef9 (correct), seq 564559956, ack 585524840, win 65392, options [mss 1460], length 0
16:27:44.445433 IP (tos 0x0, ttl 55, id 51013, offset 0, flags [none], proto TCP (6), length 40)
138.201.87.102.34989 > 192.168.1.35.443: Flags [R], cksum 0xb82e (correct), seq 585524840, win 16384, length 0
16:27:45.025532 IP (tos 0x0, ttl 128, id 1751, offset 0, flags [DF], proto TCP (6), length 44)I will re-re-boot my guests (email ones)
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@Rod-It said in Ports, rules, NAT:
138.201.87.102.34989 > 192.168.1.35.443: Flags [R],
Well that looks like the 138.x box sent a RST to the web server.
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@Rod-It said in Ports, rules, NAT:
16:27:43.348163 IP (tos 0x28, ttl 67, id 58574, offset 0, flags [DF], proto TCP (6), length 40)
138.201.87.102.42429 > 192.168.1.35.443: Flags [S], cksum 0xae6a (correct), seq 3568136006, win 29200, length 0
16:27:43.348722 IP (tos 0x0, ttl 128, id 14187, offset 0, flags [DF], proto TCP (6), length 44)
192.168.1.35.443 > 138.201.87.102.42429: Flags [S.], cksum 0x7a39 (correct), seq 1036996916, ack 3568136007, win 65392, options [mss 1460], length 0
16:27:43.388858 IP (tos 0x0, ttl 54, id 43753, offset 0, flags [none], proto TCP (6), length 40)
138.201.87.102.42429 > 192.168.1.35.443: Flags [R], cksum 0xe077 (correct), seq 3568136007, win 16384, length 0S (SYN), F (FIN), P (PUSH), R (RST), U (URG), W (ECN CWR), E (ECN-Echo) or . (ACK)
Flags [R] -> reset
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So looks to me the client sent syn S and then server sent back syn,ack S.
But then the client says no thanks with a R
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Sorry, I am not a network person.
Are we saying this is backend server dropping/rejecting or that things look ok here?
Both IIS box and Exchange will reboot shortly for completeness.
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Apologies, didn't see your latter reply
Ok so it's IIS still saying it's not happy - at least I have a focus area.
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Im not sure who the 138.x box is, but he is the client as he sends the syn... The server at 192.x box answers with syn,ack - this is normal start of a conversation.. But then the 138.x box sends R (RST) which is basically a F Off sort of thing..
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Strange that the client is sending the reset. There are very limited circumstances for that to happen, and I don't see any that I know of applying here.
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Just to be clear, this happens if I send the NAT to the IIS relay OR the Exchange box directly.
This does NOT affect clients on the LAN or any other VLAN, only requests that come in through the PfSense box.
The IIS box has it's firewall disabled for a moment, but this should not be it as internal clients work.
Both IIS and Exchange have been rebooted.
While I want to rule out AV because internal clients are working, I am happy to remove/disable it for now.
As an FYI - this is my home lab, not a production system so this is not massively critical, but a PITA nonetheless.
Something else that may or may not be relevant (I dont think it is, but i'l include it anyway).
About 2 days ago (probably some 6-8 hours before this started) I moved my domains DNS from DynDNS to CloudFlare - I have tried with and without proxied DNS, neither matter, however because the port shows as open on my public IP directly, I dont believe this to be related, though I am more than happy to be proven wrong.
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If you have time, I'd love to see one more test run with the Level of Detail set to high so I can see the packet timestamp values.
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17:16:46.428834 IP 192.168.1.35.443 > 138.201.87.102.48424: tcp 0
17:16:46.469427 IP 138.201.87.102.48424 > 192.168.1.35.443: tcp 0
17:16:46.522427 IP 192.168.1.35.443 > 138.201.87.102.61203: tcp 0
17:16:47.487447 IP 192.168.1.35.443 > 138.201.87.102.61529: tcp 0
17:16:47.886778 IP 192.168.1.35.443 > 138.201.87.102.61068: tcp 0
17:16:48.538018 IP 95.216.36.80.35970 > 192.168.1.35.443: tcp 0
17:16:48.538399 IP 192.168.1.35.443 > 95.216.36.80.35970: tcp 0
17:16:48.642150 IP 82.132.247.36.52308 > 192.168.1.35.443: tcp 55
17:16:48.645073 IP 192.168.1.35.443 > 82.132.247.36.52308: tcp 109
17:16:48.649273 IP 82.132.247.36.52308 > 192.168.1.35.443: tcp 46Guys - thank you for the help, really, it means a lot to know there are people out there willing to spend their weekends trying to help others.
I do believe 'CloudFlare' are to blame, I removed all of the DNS proxy connections once more and it's working again.
Does the above negate you wanting a further run?
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if it is working for you now, i'm happy enought
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If you're satisfied that it's working and you've found the cause then no, you don't need to do that other test run.
I'm still curious as to what was really going on. I'm not sure how a DNS proxy issue would cause your client to send a RST. Where were these DNS proxy connections configured? Via some Cloudflare GUI or is this something you're doing on the pfSense box?
If this was indeed a remote issue then that would explain why it was working fine until one day when it wasn't.
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You realise I will most likely be sticking around finding other guides and helping where I can, and no doubt I will have more questions.
So far though I really do like PfSense.
I am doing more with it within 2 months than I ever thought I would do with any networking product, I even sold my router - which by the way I really liked too (Netgear Nighthawk R7000)
CloudFlare can proxy DNS requests, so assuming my website (or in this case, webmail) points to 81.x.x.x, CloudFlare makes it their own IP, so it looks like 101.x.x.x, while my IP had the ports open and CloudFlare did too, it didnt seem to be relaying HTTPS connections to me, but instead to itself - I found an article on their site about this, something to do with how SSL works with their certificates - this would also explain why I was not seeing the traffic hit the box - which by the way I now see when someone connects to 443.
Phew... nightmare.
Apologies for the wild chase there, but just having someone else there helped me to find the issue.
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Glad we could help.
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I want to complete this topic by also stating I now know why my DNS proxy was re-enabled (sometimes we overthink things).
In PfSense DynamicDNS is an option to enable Proxying DNS - this turned it back on after I disabled it on CloudFlare directly. Makes sense why it was working then stopped. Using this option is great, but when you need HTTP/S traffic to be directed, directly and a given IP you must disable proxying (I can't find their guide right now, I've lost it already).
Here is the article linked from within PfSense that I obviously missed
https://blog.cloudflare.com/announcing-virtual-dns-ddos-mitigation-and-global-distribution-for-dns-traffic/
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I just wanna know why your IP is scanning me like crazy... :P Or are you behind some kind of carrier NAT?
