Cisco Firewall :: 2901 To Avoid SMTP Inspection On Zone Based Firewall
Jun 21, 2011
We had a problem with SMTP inspection dropping some regular emails (Cisco 2901 IOS 15.0).Incoming mails are going thru Spam and Virus Blocker so that bypassing SMTP inspection is not security issue in this case.
I have a Cisco 2901 which terminates a Class C address pool. I have split the Class C address pool into 3 sub-nets and 2 zones and created a non-addressable pool (private pool):
dmz-zone : x.x.x.0 TO x.x.x.127 (x.x.x.0/25) in-zone: x.x.x.128 TO x.x.x.159 (x.x.x.128/27) & x.x.x.160 TO x.x.x.191 (x.x.x.160/27) private-zone: 192.168.x.0 TO 192.168.x.255 (192.168.x.0/24)
I have configured private-zone NAT to use address pool x.x.x.161 TO x.x.x.189 within the in-zone.
dmz-zone - are servers for : DNS, Syslog, SIP & HTTP/HTTPS in-zone - is a SMTP mail server which is behind VPN Gateway/NAT, TomCat (Application Server) and PostgreSQL Server private-zone - is where all standard users are operating from and they can access the SIP & HTTP/HTTPS servers within dmz-zone My problem is that I cannot seem to configure the ZBFW to allow the dmz-zone HTTP/HTTP server to redirect to in-zone TomCat server.
I do not want to make the TomCat server generally visible and am instead using the Apache proxy/ajp13 to connect from dmz-zone server to in-zone server.However I cannot seem to get anything (including icmp) to work from dmz-zone to in-zone.
I have Policy:
POLICY-DMZ-IN (dmz-zone to in-zone) which has: any any udp/tcp inspect any any icmp inspect unmatched traffic DROP/LOG
But I still cannot get anything from dmz-zone to in-zone...Could the POLICY-DMZ-IN be being overridden by other dmz-zone to out-zone policies?
NOTE: I have routing rules for each of various sub-nets and all out-zone to dmz-zone, out-zone to in-zone and private-zone to out-zone, in-zone and dmz-zone routing works ok, so it appears problem is with ZBFW not routing table.
I've been trying to configured Websense urlfiltering using ZFW feature on my Cisco 881G router. The router is running on IOS 15.0(1)M with Advanced IP Services. And I have confirmed it supports urlfilter feature.
This is what I tried to accomplish but IOS version 15.0x seems to have different command set. ----------------------- class-map type inspect httptraffic match protocol http parameter-map type urlfilter param server vendor websense 10.20.30.40 [Code]...
I have two 1811's connected in a lab using a ipsec vpn tunnel (using a switch to simulate an internet connection between them).I am trying to configure one of the routers as a ZBPF just to allow a remote windows login (DC on the firewalled side, workstations on the other side).I'm trying to verify that the zbpf is working, but it doesn't seem to stop anything. I had match icmp added to the class-map, but took it out to test if icmp would fail. It didn't. Basically, I don't think the firewall is working at all. Any thoughts on how I can configure this so that the policies will work between zone-pairs?
Here's an quick drawing:
Here are the configurations:
Local router: hostname sdc-1811-LocalLab ! boot-start-marker boot-end-marker ! no aaa new-model ! resource policy
I am getting ready to deploy a 3945 ISR to serve as an internet and core router for and remote site. I will be terminating a site-to-site VPN tunnel on it and also configuring a zone based firewall config between my "outside" (internet link) and "inside" (all internal nets). My question is about how to approach securing the WAN interface with the Zone based FW in place?what kind of ACL do I need beyond those allowing and restricting remote access to the outside ip?
I have a cisco 1841 router , and i want to configure zone based firewall on it. But the document of zone based firewall only said that "after 12.4(6)T" can support zone based firewall. I use the ios " c1841-ipbasek9-mz.124-15.T9.bin ", but it can't support ZFW. What kind of ios support ZFW. for example: ipbase, ent base, ip service ,advent etc.
we are experiencing performance issues on ASR 1004 with ZBF as our campus edge router.Symptoms:
- sending small packets from inside zone to outside zone, for example UDP packets without payload - this way I can generate up to 150.000 pps traffic (testing with packeth software, but we have had a real example with some kind of worm/virus) - CPU load is about 1% (yes one!) to 2% all time !! (weird) - ASR response to pings rises very quickly up to 5 seconds which makes box unusable dropping everything what goes through ZBF (so internet connection is gone) - if I do the ping directly from box, it seems to work fine (no rules from self to outside zone in ZBF) - if I remove interfaces from inside and outside zone (so disabling ZBF) and do the test again, ASR response goes from normal (0.2ms) up to 2ms (still sending 150.000 pps) and everything seems to work fine)
According to Cisco Datasheets: routing, Qos, Zbf ... on ASR 1000 with RP1, ESP10 should be done in hardware with up to 17.000.000 pps performance.
I am confiuring ZFW on a Cisco 2951 Router. The router has the following interfaces: [code]Port Channel 1, 1.5, 1.10, 1.15, 1.20 have been added to the zone called IN-OUT. All the subinterfaces correspond to an internal VLAN.The router is connected to a MPLS network and has a BGP peer on interface MPPP. Over the MPLS network, an ecrypted DMVPN tunnel to HQ has been built (tunnel 0). EIGRP is the routing protocol running over the tunnel.Traffic coming in from HQ has to be firewalled on this router (don't ask me why!!). As a result, I am configuring ZFW on this router.
1-The router itself does not need to be protected, only the servers in the remote offices. That being said, I am not planning to create any self zone on this router. I don't want to break BGP, therefore the MPPP interface will NOT belong to any zone. Is this the correct way to do it?
2-The tunnel 0 interface will belong to OUT-IN zone that will protect all incoming traffic into this site from HQ. So when writing class-maps for the traffic coming INTO this site, do I need to write any class-maps for EIGRP or ESP? My guess is no, since that traffic will not be coming into the site, but rather just terminating on the router.
I'm sure this is simple to resolve. I just bought a new Cisco 2901 ISR Router. How do I configure the Cisco 2901 ISR Router for Zone Firewall? The "zone" command is not recognized and does not show up in the "?" list in config or user modes -
I'm having a few problems at the moment with a zone based firewall setup. The more I looked into the problems the more I question whether I need the ZBF or not.My network is pretty simple. 1 Internet connection and 1 LAN interface and a few site to site vpns to the router.So what do people think to having this kind of set up and not using a ZBF?
I am looking to implement Zone-Based Firewall on some 2900 series routers (2911 and 2921.) Based on some research I've done it looks like the cisco2911-sec/k9 and cisco2921-sec/k9 bundles should be all I need. Is this correct, or is there some other licensing component that needs to be enabled for me to implement Zone-Based Firewall?
I'm having an issue accessing a clients router on the WAN interface with Cisco config pro. I can get CLI access with SSH without any issue. I have port 22 and 443 allowed as management access from my public IP - SSH working fine but config pro being refused connection, Possibly a certificate issue?
we have an ASR1002 running zone-based-firewall with 2 zones:
I have a common ZFW-configuration on that interfaces, e.g.
<code> class-map type inspect match-any pass_cmap_in match access-group name pass-ipv4-in ! class-map type inspect match-any ph_cmap_in match access-group name ph-ipv4-in
There is some basic stuff in the Access-Lists; direction ph-ipv4-in contains basically "permit ip any any" and ph-ipv4-out contains some permits for certain services, but nothing else. The pass-ipv4-in/out ACL contains particularly the udp-500/4500-stuff as well as gre/esp/ah.
The xconnect is only built up correctly when I configure the interface in the zone_outside. The destination for the xconnect is an ASR9k. If I do not configure the zone on the L2VPN-Interface, only arp-packet are allowed to tgo through the tunnel.
The L2VPN connects a branch office to the network of "PH". Now the trouble starts: when they are putting a host in the branch office, DHCP via the L2VPn works fine, they can ping anything from the branch office-PC in their local network and reach all internal servers etc.
BUT if they want to go to a destination outside their network, it will not work properly. For example, the branch-office-PC can ping 18.104.22.168 fine, but when they try to connect to a website, e.g. www.google.com, they run into a timeout. Netstat says, that the http-syn is sent, but no ack is received.
whereas x.y.225.250 is the PC connected via L2VPN in the branch office to their local lan. When they put the same machine in their local lan directly behind the router (without l2vpn) everything works fine. When I switch off the firewall on the Gi0/0/0-Interface, the PC from the branch office also reaches its destination, so for me it looks like the firewall inspects the traffic going via Gi0/0/1 and L2VPN, what in my opinion, it should not do....
We are testing a Zone Based FW config since 1month, everything run smooth but we're having problem ( big slow speed access ) when a user try to reach a website on a non-standard port ( 8080 in that case ). All the trafic stay in our LAN, using a IPSEC/EZVPN connection between the 2 sites.As soon as I have disabled the Zone Based FW, the speed was much better.
I'm sure I'm missing a parameter to fix that problem but I tried many different options and I didn't find anything yet. All the routers are Cisco 1811 running adv IP Services 15.1.2.T1 IOS.A port-map has been created to map the port 8080 to the HTTP protocol for the inspection.The PC will have an IP address in the 10.2.2.x/24 and will access a server on 10.2.3.x/24, both devices are part of the zone private in each site/LAN.All the access between sites are managed by an ASA; the IPSEC/EZVPN peer.Little summary, it's gonna be something like : SiteA with a PC on private zone then on public zone for the EZVPN to SiteB on public zone and then private zone to access the server in the LAN.
I'm trying to configure a zone-based firewall on an SR520 and am confused about the 'not' criterion. The 'zone-design-guide' says (my stress): Class- maps define the traffic that the firewall selects for policy application. Layer 4 class-maps sort the traffic based on these criteria listed here. These criteria are specified using the match.where my intention is to let only LAN hosts with IPs in the range 192.168.1.1 to 192.168.1.7 out through the firewall. There may be an easier way of doing this which I'd be pleased to hear about. But, even if there is, I'd also be interested to know what I'm doing wrong in the above.
I have set up a zone-based policy firewall with HA on two 2911 routers as per the Cisco security configuration guide, for an active/passive LAN-LAN cluster. All works as expected, but there is one problem I find: when the control link between the two devices fails, they go into an active/active state as each member assumes it's the last surviving member. The ARP entries for the Virtual IPs on the neighboring devices point to the device that last claimed the active role (usually the standby device). This works in a way, just sessions don't get synched anymore (control link is the same as data link). Now when the link comes back up, the preemtion works and the active, former standby device goes back to standby. But the ARP entries on the neighboring devices still point to the standby device and nothing goes (also sessions established during the active/active state are lost due to resync with the now active member).
This is a single point of failure and what I need is a way to mitigate that. Under:
redundancy application redundancy group 1 control <interface> protocol 1
only one control interface is allowed. Other manufacturers with similar functionality provide for the possibilty of a backup control link, for example the internal LAN interface or a dedicated backup link.
How would I go about that? Maybe use a port-channel for the control/data link (but I'm out of interfaces)?
The problem I am having is very strange and I have tried to upgrade the IOS on the 1841 to solve the problem but no luck. The issue is when I enable Zone Based firewall security on of the 1841 routers two VPN site-to-site tunnels stops working. If I turn off CEF (no ip cef) then the traffic for both tunnels works. Someone told me that the Zone Based firewall must have a match for the VPN traffic and I created that with ACL 160 and 161 but it did not solve the problem.
Current IOS is below.
Cisco IOS Software, 1841 Software (C1841-ADVSECURITYK9-M), Version 15.0(1)M9, RELEASE SOFTWARE (fc1) Technical Support: [URL] Copyright (c) 1986-2012 by Cisco Systems, Inc. Compiled Tue 11-Sep-12 23:58 by prod_rel_team
I have a simple setup where I have a 2911 router with three interfaces, Inside, Outside and a second "Inside" interface which is labelled as a DMZ. The Zone Firewall applied to the "DMZ" is actually Inside (until I can work through problems). I need to be able to access a device on the DMZ via its external IP so I have designed NAT to use IP Nat Enable commands. This is now working for me fine. However, since utilising IP Nat Enable, my zone firewall now denies return TCP / UDP traffic and consequently I no longer have any internet access. Looking at the syslog messages, the reason for this is that the router is denying these return flows not because they are matching the outside-to-inside policy, but rather they are matching the outside-to-SELF policy. The router seems the detect that the internet traffic is being returned to SELF, when in reality the NAT rule should pick this up and forward it to inside. I can understand why this is happening, because I am NATting all private / inside traffic behind the external IP of the router, which is assigned to the Gi0/0 interface. [code]
I am trying to understand zone base firewalls? I attempted to make the ip address 10.2.22.231 available to the outside world using port 80 and 443 on external interface(4) public IP address. I can see hits on the access list and Nat entries but it's not getting through.
Here is the config. crypto pki trustpoint TP-self-signed enrollment selfsigned subject-name cn=IOS-Self-Signed-Certificate- revocation-check none [code].....
I am a novice with networks but do have a fair understanding of networks. I have a small business network, utilizing a RVS4000 router (Firmware V2.0.27)I am attempting to set up firewall rules to block certain web sites at certain times.I have successfully set up rules using source and destination ranges, to deny service 24 hours a day everyday.
However and here is the problem when I attempt to edit any of the rules (I want to change the time to certain hours of the day) it allows me to edit the rule but when I attempt to save I get an error message up saying there are invalid characters and it will not save the changes?create the whole thing with the changes I want it works fine, is this a known bug?
We are using the newest release of AD Agent (22.214.171.124.1, built 598). The ASA Firewalls 5520 are having the software release 8.4(3)8 installed.When somebody tries to connect thru the Identity based firewalls from a citrix published desktop environment (PDI) the connection is not possible. Checking the ip-of-user mapping on the firewalls (show user-identity ip-of-user USERNAME) mostly doesn't show the mapping of the USERNAME and the PDI the user is logged in. The user-of-ip mapping of the PDIs IP-address shows mostly other users, which then are used to authenticate the acces thru the firewalls.
What is interesting, that on the AD Agent using "adacfg.exe cache list | find /i "USERNAME"" i can't see the PDIs IP-address neither because it is mapped to another user.Is Citrix Published Desktop environment supported to connect thru Identity based Firewalls? How AD Agent, Domain Controllers and Firewalls are working together? On the firewalls with "show user-identity ad-agent we see, the following:
I have multiple customers and servers behind my ASA5510s. After moving a new customer with an FTP server behind the firewalls, they immediatly had issues with customers connecting to their FTP server. I had the default inspection rules running regarding FTP. After removing the "inspect ftp" from the global policy their issues went away. Since this is a larger customer I can't force them to change their server, I need to accomodate and fix this on the firewall. I left the "inspect ftp" command out and there have been sporatic issues from other customers, unable to connect to outside FTP servers from the terminal servers and timeouts and disconnects to our own FTP servers.
This is what I "think" is the solution.. I added a second inspection policy after the default one and only added "inspect ftp" to it. Then I used the "exclude" option to exclude the new customer. That new customer is fine and things are better, but still not working right. Does the following config accomplish what I want?? Does the exclude ACL get what I need or do I need an "include" or permit statement in that ACL?
having a very strange problem with a Cisco 1861 running - Cisco IOS Software, C1861 Software (C1861-ADVENTERPRISEK9-M), Version 12.4(24)T5
I have suddenly started to get performance issues with downloads and access through the ZBF. Without the firewall enabled and just having NAT enabled and routing , downloads perform as expected - ( have been using Itunes download as test file ) - with the ZBF enabled , and the necessary rules installed to inspect & allow traffic - downloads stall - and the only way to get the downlaod to start again is to pause , then resume. The stalls are anything between the first 25 - 120 secs.
I have debugged and performed packet traces - but cant see anything untoward. I have also placed another router ( just a cheap Belkin ) on the ADSL service and again , the downloads work as expected.
one further thing to add is that when im tunneling through the firewall ( VPN ) , then downloads do work as expected - suggesting that the issue is with native HTTP(s) traffic..I have upgraded from T4 to T5 - and the symptons still remain - I am thinking that these may have been introduced when i upgraded to T4 a few monthes ago.
I have a 2800 router connecting a small office to the Internet. I am using zone-based firewall to provide protection. The small office also needs to connect to another office. The 2800 is at the small office and an ASA at HQ. I successfully established the VPN connection and have allowed Internet access for the small office. The purpose of this post is my zone-base fw policy doesn't appear to be as secure as it could be.
2800 - I have defined two zones (inside and outside). Traffic from the inside to the outside is inspected expect for the traffic to the other office. I allow traffic to the other office to "pass" zbfw. Because the traffic "passes" zbfw, I have to "pass" the same traffic for the outside to in policy. The ASA has "sysopt" to allow VPN traffic to bypass the outside_acl. Do routers and zone-based firewall have a similar feature?
I have a 3845 ISR that I have been managing for a couple years that has a traditional ACL based config. We just purchased a new 3845 for redundancy and it arrived with the zone based config from Cisco. Any opinions on whether I should take the existing router to a zone based config or should I configure the new router with traditional ACL config that I am more comforatable with?
ASA 5520 running 8.4.5:We had an issue with a remote SMTP connection getting screwed up as a result of ESMPT inspect.It took me 3 hours of troubleshooting the SMTP connection before finally figuring out that the firewall was the culprit. What really through me off was that I saw nothing in the ASA logs (warning and above) that showed packets were being dropped. I'm probably crazy but I thought I remembered seeing entries in the log when packets were dropped due to a type of inspection (specifically, I remember entries in the log saying something to the effect of packet dropped due to ESMPT inspect, packet too big). My quesiton to Cisco TAC was: Is there a simple way to have the log give a warning every time a packet is dropped due to any inspection rule, just like we can see any drops due to ACLs? So far the only answer has been a complex list of log changes to allow debugging and notifications of certain events. This isn't something I want to roll out to all my ASAs.
We have several customers running ASA 8.4x code and all seem to be plagued with the ESMTP inspection bug CSCtr92976.I have tested this in the lab with an ASA 5505 running 8.4(1), 8.4(2) and 8.4(4)1 & 8.4(4)3 and the behaviour is always the same. I have an Exchange 2007 server and I can see in the logs the following messages:
This is with the default ESMTP inspection enabled. I have also created a custom ESMTP inspection policy that does nothing but log and the behaviour is still the same. Sometimes traffic will pass but most of the time it won't. The workaround is to just disable the ESMTP inspection.
By default ASA applies DNS packet inspection with a default (maximum) packet size of 512bytes as recommended by RFC 1035, anything above is dropped.
I have a customer that is trying to use larger packet sizes due to extension mechanisms for DNS defined in RFC2671.
My question is , is it safe to increase the default packet size in the DNS inspection thus applied globally for all DNS traffic, or should / can we apply a policy that applies only to this specific customer ?