501e: Access internal SSL site using external domain name

[58sniper]

Greets!

I don't do much Cisco stuff, so I don't recall what this is called.

I have a new Exchange box installed, and it it's working beautifully. Internal users access it via

https://servername/

and external users via

https://mail.domainname.com/

without a problem.

We'd like internal users to access it using the external domain name, but we're not able to establish a connection. We get name resolution, which points to the public IP address, but the firewall isn't letting the traffic through. I'll add that the same thing happens if we try http instead of https. Someone in my office said it sounds like a SPI issue. I'm at a loss as to what to look for.

Any ideas?

Pat Richard, MCSE(2) MCSA:Messaging, CNA(2)

 

[penguinroundup]

Are you running your own DNS? If so, you should have an A record for mail.domainname.com pointing to the internal IP of your mail server.

the client should use your internal DNS servers for name resolution.

HTH

 

[58sniper]

We're running internal DNS for our internal AD infrastructure, but not for our public domain name.

Pat Richard, MCSE(2) MCSA:Messaging, CNA(2)

 

[NetworkGhost]

If your running internal DNS then create a zone for the public domain name and add an A Record there. That is the easiest.

 

[wirelesspeap]

causemaker,

What you are trying to accomplish can be easily done
via dns doctoring. This will work:

static (inside,outside) 1.1.1.1 192.168.0.1 dns netmask 255.255.255.255

basically, when internal do a "nslookup" of the public domain name, the Pix firewall will "doctored" the return
dns querry so that you internal will be directed to an
internal ip address of the exchange server.

Try it and it will work.

wirelesspeap

 

[58sniper]

Okay - making sure I understand it before I do it, the syntax is the public IP address first, the private IP address second, correct?

Pat Richard, MCSE(2) MCSA:Messaging, CNA(2)

 

[NetworkGhost]

I would imagine you already have a static statment for your email server in your Pix. Just modify that. If not then yes the outside address comes first. The only thing is you say you have a 501. Do you already have a static assigned or are you doing port forwarding? Post your config if not sure.

 

[58sniper]

Okay - this was low priority, and I've now finished some other projects and am coming back to this.

I'm doing static assigned. Here is my current config, before making any suggested changes (hopefully, I've removed everything that shouldn't be public):

Pix# show running
: Saved
:
PIX Version 6.3(3)
interface ethernet0 auto
interface ethernet1 auto
nameif ethernet0 outside security0
nameif ethernet1 inside security100
enable password <REMOVED>
passwd <REMOVED>
hostname Pix
domain-name <REMOVED>
fixup protocol dns maximum-length 512
fixup protocol ftp 21
fixup protocol h323 h225 1720
fixup protocol h323 ras 1718-1719
fixup protocol http 80
fixup protocol ils 389
fixup protocol rsh 514
fixup protocol rtsp 554
fixup protocol sip 5060
fixup protocol sip udp 5060
fixup protocol skinny 2000
fixup protocol smtp 25
fixup protocol sqlnet 1521
fixup protocol tftp 69
names
access-list INTERNET permit icmp any any echo-reply
access-list INTERNET permit icmp any any time-exceeded
access-list INTERNET permit icmp any any unreachable
access-list INTERNET permit tcp any host <REMOVED>.235 eq www
access-list INTERNET permit tcp any host <REMOVED>.237 eq smtp
access-list INTERNET permit tcp any host <REMOVED>.237 eq www
access-list INTERNET permit gre any any
access-list INTERNET permit tcp any host <REMOVED>.235 eq https
access-list 101 permit ip 192.168.1.0 255.255.255.0 192.168.100.0 255.255.255.0
pager lines 24
logging on
logging timestamp
logging monitor notifications
logging buffered notifications
icmp permit any inside
mtu outside 1500
mtu inside 1500
ip address outside <REMOVED>.234 255.255.255.248
ip address inside 192.168.1.1 255.255.255.0
ip audit info action alarm
ip audit attack action alarm
ip local pool vpnpool 192.168.100.100-192.168.100.200
pdm location 192.168.1.2 255.255.255.255 inside
pdm location 192.168.1.20 255.255.255.255 inside
pdm location 192.168.1.21 255.255.255.255 inside
pdm location 192.168.1.22 255.255.255.255 inside
pdm history enable
arp timeout 14400
global (outside) 1 interface
nat (inside) 0 access-list 101
nat (inside) 2 192.168.1.20 255.255.255.255 0 0
nat (inside) 1 0.0.0.0 0.0.0.0 0 0
static (inside,outside)  <REMOVED>.237 192.168.1.21 netmask 255.255.255.255 0 0
static (inside,outside)  <REMOVED>.235 192.168.1.23 netmask 255.255.255.255 0 0
access-group INTERNET in interface outside
route outside 0.0.0.0 0.0.0.0  <REMOVED>.233 1
timeout xlate 3:00:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h225 1:00:00
timeout h323 0:05:00 mgcp 0:05:00 sip 0:30:00 sip_media 0:02:00
timeout uauth 0:05:00 absolute
aaa-server TACACS+ protocol tacacs+
aaa-server RADIUS protocol radius
aaa-server LOCAL protocol local
aaa-server partnerauth protocol radius
aaa-server partnerauth (inside) host 192.168.1.21 kccrocks timeout 5
url-server (inside) vendor websense host 192.168.1.21 timeout 5 protocol TCP version 1
filter url http 0.0.0.0 0.0.0.0 0.0.0.0 0.0.0.0 allow
http server enable
http 0.0.0.0 0.0.0.0 inside
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
floodguard enable
sysopt connection permit-ipsec
crypto ipsec transform-set myset esp-3des esp-md5-hmac
crypto dynamic-map dynmap 10 set transform-set myset
crypto map mymap 10 ipsec-isakmp dynamic dynmap
crypto map mymap client authentication partnerauth
crypto map mymap interface outside
isakmp enable outside
isakmp identity address
isakmp policy 10 authentication pre-share
isakmp policy 10 encryption 3des
isakmp policy 10 hash md5
isakmp policy 10 group 2
isakmp policy 10 lifetime 86400
vpngroup kccvpn address-pool vpnpool
vpngroup kccvpn dns-server 192.168.1.21
vpngroup kccvpn wins-server 192.168.1.21
vpngroup kccvpn default-domain kensington.org
vpngroup kccvpn split-tunnel 101
vpngroup kccvpn idle-time 1800
vpngroup kccvpn password ********
telnet 0.0.0.0 0.0.0.0 inside
telnet timeout 5
ssh timeout 5
console timeout 0
terminal width 80
Cryptochecksum: <REMOVED>
: end
Pix#

The line that reads

static (inside,outside)  <REMOVED>.235 192.168.1.23 netmask 255.255.255.255 0 0

Is the line that maps a public IP to my internal mail server.

Pat Richard, MCSE MCSA:Messaging CNA
Want to know how email works? Read for yourself -

http://www.ietf.org/rfc/rfc2821.txt

 

[sla07]

i dont think the statement below will work...

static (inside,outside) 1.1.1.1 192.168.x.x dns netmask 255.255.255.255


i just tried it on my internal network and it blocked off all my internet traffic....

 

[boymarty24]

Perhaps your public static IP is the same as your interface IP?

And i recommend that you use your internal dns instead of the doctor function. Just create the zone and add the records.

 

[58sniper]

In taking that route, I'm assuming I'm going to need to also create an A record for the website and point it to the external host, correct? Otherwise, internal people won't be able to access their website.

Pat Richard, MCSE MCSA:Messaging CNA
Want to know how email works? Read for yourself -

http://www.ietf.org/rfc/rfc2821.txt