Blocking SSH - Firewall Rule Troubles - SOLVED

johnpoz

Ok first thing I see is you have that allow any any rule on multiple interfaces.. So wan_shaw has any any to public net, and there is no blocks on that interface. So when I do a trace to that IP I hit..

13 49 ms 49 ms 47 ms 66.163.70.2
14 55 ms 52 ms 64 ms 64.141.125.254

What what connection is that 66.163.. So you have that allow on all your interfaces?

acherman

Looks like that 66.163.70.2 is the router on our Shaw WAN - the address that I hit there is 64.141.127.249.

johnpoz

Ok I put in a rule on your shaw wan to block ssh to your .250, 251, 254

And I it looks blocked now.

johnpoz

Ok I added logging to the rule, and you can see blocked from my attempt to all 3 of them

Your going to want to go through these connections and block services to pfsense interfaces. So for example I was able to remote in.. that should clearly be something you only allow when you want it.. And put in specific rule for ;)

blockedinlogs.png_thumb

acherman

Okay, so I had rules just like to start with (see first post). Weird. So, which address were you able to get in on?

johnpoz

I could ssh to all 3 of the ips. And https is open on all three as well.

Ssh is blocked now.. your going to want to block ports your gui is listening on.. https, I didn't check http.. And any thing else you might have running.. dns for example

C:>dig @64.141.125.254

; <<>> DiG 9.9.5-W1 <<>> @64.141.125.254
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12950
;; flags: qr rd ra; QUERY: 1, ANSWER: 13, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;. IN NS

;; ANSWER SECTION:
. 87258 IN NS b.root-servers.net.
. 87258 IN NS l.root-servers.net.
. 87258 IN NS f.root-servers.net.
. 87258 IN NS i.root-servers.net.
. 87258 IN NS e.root-servers.net.
. 87258 IN NS d.root-servers.net.
. 87258 IN NS a.root-servers.net.
. 87258 IN NS g.root-servers.net.
. 87258 IN NS j.root-servers.net.
. 87258 IN NS h.root-servers.net.
. 87258 IN NS m.root-servers.net.
. 87258 IN NS k.root-servers.net.
. 87258 IN NS c.root-servers.net.

;; Query time: 110 msec
;; SERVER: 64.141.125.254#53(64.141.125.254)
;; WHEN: Tue Feb 10 16:10:40 Central Standard Time 2015
;; MSG SIZE rcvd: 239

DUDE!!!! you have a recursive dns listening on the public net!! That is normally not good!! Bock that as well!!!

acherman

Damnit!!! >:(

johnpoz

This why you normally don't do a any any rule on your wan ;)

acherman

You lost me with the recursive DNS part.

Also, so, without the any any rule, how would I pass all routed traffic to the the commercial hosts on that net?

johnpoz

Recursive – I can ask you for any domain on the planet..

; <<>> DiG 9.9.5-W1 <<>> @64.141.125.254 www.google.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 37163
;; flags: qr rd ra; QUERY: 1, ANSWER: 16, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;www.google.com. IN A

;; ANSWER SECTION:
www.google.com. 135 IN A 207.34.103.20
www.google.com. 135 IN A 207.34.103.54
www.google.com. 135 IN A 207.34.103.29
www.google.com. 135 IN A 207.34.103.30
www.google.com. 135 IN A 207.34.103.59
www.google.com. 135 IN A 207.34.103.39
www.google.com. 135 IN A 207.34.103.50
www.google.com. 135 IN A 207.34.103.40
www.google.com. 135 IN A 207.34.103.35
www.google.com. 135 IN A 207.34.103.55
www.google.com. 135 IN A 207.34.103.45
www.google.com. 135 IN A 207.34.103.34
www.google.com. 135 IN A 207.34.103.49
www.google.com. 135 IN A 207.34.103.44
www.google.com. 135 IN A 207.34.103.24
www.google.com. 135 IN A 207.34.103.25

;; Query time: 69 msec
;; SERVER: 64.141.125.254#53(64.141.125.254)
;; WHEN: Tue Feb 10 16:18:15 Central Standard Time 2015
;; MSG SIZE rcvd: 299

You then go look it up for me.. This is can be used for HUGE amplification attacks.. Do you not read the news? ;)

Normally with a transit network, so pfsense interface is not exposed to the any any rule with a downstream router. My point to the any any, is doing so normally exposes stuff that might not of thought of.. Like your web gui to your firewall, ssh, dns, etc.

If you want to continue to use the any any - then create a specific block rule containing all the stuff you don't want to expose for pfsense interface in that segment, and then make sure its applied on the appropriate interfaces where that traffic comes in.

Or make the any any specific to the IPs the customer is using and not true any any.. so like 64.141.125.1 to 249 for example..

acherman

For blocking the services to all of my router interfaces, can I just change the alias you made to include the WAN addresses as well? And any others that I need?

acherman

Sure I read the news, but I get all caught up with all the Kardashian stuff. It's super duper fascinating.

Okay, so I'm working on creating rules right now. For the recursive, just block DNS on the WAN interfaces?

And thanks again. You're a huge life saver here. I really appreciate your time and help.

johnpoz

Sure you can create an alias to include IPs and ports.. But you could also just change the any any rule you have to not be the full network, make it say 64.141.125.1 to .249.. Now this allows all there stuff to be open.. But the default deny would block access to the IPs you would use on pfsense for say carp, etc. etc.

That is the way I would do it so I was sure not to miss a service or bring up a new services and forget to update the blocking rule.. Always better to have deny deny and anything that is allowed have to have a rule, then to allow a rule that is any any, and now new services are open when they you didn't want them to be.

doktornotor

Regardless of any FW rules - do you need DNS listening on WAN? If not, then just do not bind it to WAN interfaces.

acherman

Okay, I think your way sounds much better (obviously). How can I make the rule for a range like that? I'm looking…

And no, we don't need to listen for DNS on the WAN - only outbound requests. Although, I don't have DNS Resolver turned on. Or am I missing it somewhere else?

acherman

Alrighty then, I created an alias for those Public IPs that need full access (64.141.125.21-.249), and changed the permit any any rule to the alias as the destination.

johnpoz

And and a quick test shows can not get to the web gui, and can not query dns. Much better setup

C:>dig @64.141.125.254

; <<>> DiG 9.10-P2 <<>> @64.141.125.254
; (1 server found)
;; global options: +cmd
;; connection timed out; no servers could be reached

acherman

Thanks for your help. You rock!!!

johnpoz

Here to help dude, sometimes I get cranky and rambunctious with some of my wording.. But just here to help people enjoy their pfsense setup as much as I do. Never take anything I say personal, quite often its the beer or bourbon talking as well ;) heheeh

It can get frustrating sometime with same questions over and over and over again with people unwilling to do their own learning and reading. Nice to have a problem other than people with ftp and unbound questions ;)