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SIP Trunk and SIP Phones coming in over VPN

Hello! 

I´m a newbie with sophos UTM9, and after lots and lots of angry customers from cisco with there smaller ASA´s I was looking into a alternative solution to ASA5505 and ASA5510. So I stumbled along the UTM9 firewall solution. It looks like a great product, and so I started testing it in my home lab environment. (CUCM 8.6.2, 2901 cisco Router as Voice Cube and such...) 

Setup:

UTM9 running on a Static IP at home lab Version: 9.106-17

ASA5505 connecting from customer site via IPSEC-VPN 

Call Manager, 2901 connecting to a SIP Trunk via 3. NIC 

Now I have the SIP Trunk working one way (Calls coming in work, Outgoing calls won´t transfer ) with the VOIP SIP proxy. 

That is one problem I am having. I THINK it might be due to RTCP. I had a log entry that showed a denied:

RTCP
62.180.x.x:10273→80.81.x.x:16489

I tried to help with a NAT rule sending everything from the 62.180 ip on the External interface to the 2901 Router. Now I don´t see any denies any more, but the call still does´t go through. Any Hints and tips on this? 

Now with the SIP Inspection active, I have another Problem. I have a 5505 ASA that I take along into hotels, customer sites and such, and have a dumb 3905 SIP phone from cisco and a 7965 SCCP. The ASA connects via VPN (IPSEC Site to Site) just fine. the 7965 also registers and works as long I don´t want to call out. but the SIP Phone will not register as long as the SIP Inspection is active. But the trunk won't work if it isn´t... 

Is there any way to exclude the vpn connection from SIP Inspection? I´d really love to get this solution working, and convince a few customers to give Sophos a shot, instead of Cisco. 

Thanks a lot for your help!


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  • Almost right - the 2901 doesn´t have to accept traffic from the vpn 172.30.199.0. the SIP phones located there, have to connect to the CUCM. Everything telefonwise is done by the CUCM. The Phones never talk to the 2901, only the CUCM. The CUCM sets up calls, and receives calls from the 2901, which it then sends to the phones. All Phones on 172.30.200.0 work. only once you move them to the test office.. the sip connection to the CUCM doesn´t work, they don´t register. 

    and yes to all 3 counts [;)]
  • So, VoIP calls all go: phone CUCM2901ProviderOutside World?  And calls between phones internally go: phone CUCMphone with no traffic passing directly between the two phones?

    I just noticed that the SIP Proxy is in 'Expectation: Any' mode.  I would have expected "Strict" if the 2901 exchanges all messages with the VoIP provider.

    If that's all correct, then I wonder if the CUCM knows to route 172.30.199.0/24 traffic to 172.16.100.254.  Does the UTM have a Static Route for traffic to 172.30.200.0/24?

    Cheers - Bob
  • absolutely correct. You hit it dead on the point [:D] 

    yes, the SCCP Based Phones work just fine at the vpn site, that works. Just the SIP Based phones don´t. Routes and everything else is working. Emails, RDP, Sharepoint, SSH and such. the ONLY thing that won't work, is the SIP Based phones.

    I wasn´t sure what "strict" meant, and "any" was default enabled. Could "Strict" help?
  • In "Any" mode, I think the SIP proxy catches everything that passes by.  Changing to "Strict" could fix this issue.

    Cheers - Bob
  • o.k. switched it, but to no avail.. 

    the MAC: 00:25:90:32:2c:5f That I have been searching for, is actually the INTERNAL NIC of the UTM box. 

    So reading this:

    00:13:32 SIP
    172.30.199.49 : 4960

    172.30.200.29 : 5060
    [ACK] len=1420 ttl=63 tos=0x00 srcmac=0:25:90:32:2c:5f

    Coming from the internal NIC, With no Destination MAC... whats up with that?
  • Please show the line from the full log file as well as several lines before it.

    Cheers - Bob
  • atlast I found the other log! [:D] Still new to this... 

    o.k. this IS interessesting:

    2013:11:15-08:00:27 mail ulogd[4513]: id="2000" severity="info" sys="SecureNet" sub="packetfilter" name="Packet logged" action="log" fwrule="0" outitf="eth2" mark="0x1bd" app="445" srcmac="0:25:90:32:2c:5f" srcip="172.30.199.49" dstip="172.30.200.29" proto="6" length="1420" tos="0x00" prec="0x60" ttl="63" srcport="4966" dstport="5060" tcpflags="ACK" info="nf_ct_sip: dropping packet"
    2013:11:15-08:00:30 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.57" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:00:41 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.24" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:00:48 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.252" dstip="172.25.1.42" proto="17" length="272" tos="0x00" prec="0x00" ttl="62" srcport="32768" dstport="162" 
    2013:11:15-08:00:52 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.20" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:01:03 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.46" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:01:10 mail ulogd[4513]: id="2000" severity="info" sys="SecureNet" sub="packetfilter" name="Packet logged" action="log" fwrule="0" outitf="eth2" mark="0x21bd" app="445" srcmac="0:25:90:32:2c:5f" srcip="172.30.199.49" dstip="172.30.200.29" proto="6" length="1420" tos="0x00" prec="0x60" ttl="63" srcport="4938" dstport="5060" tcpflags="ACK" info="nf_ct_sip: dropping packet"
    2013:11:15-08:01:10 mail ulogd[4513]: id="2000" severity="info" sys="SecureNet" sub="packetfilter" name="Packet logged" action="log" fwrule="0" outitf="eth2" mark="0x1bd" app="445" srcmac="0:25:90:32:2c:5f" srcip="172.30.199.49" dstip="172.30.200.29" proto="6" length="1420" tos="0x00" prec="0x60" ttl="63" srcport="4938" dstport="5060" tcpflags="ACK" info="nf_ct_sip: dropping packet"
    2013:11:15-08:01:14 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.53" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:01:25 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.27" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:01:36 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.31" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:01:42 mail ulogd[4513]: id="2000" severity="info" sys="SecureNet" sub="packetfilter" name="Packet logged" action="log" fwrule="0" outitf="eth2" mark="0x1bd" app="445" srcmac="0:25:90:32:2c:5f" srcip="172.30.199.49" dstip="172.30.200.29" proto="6" length="1420" tos="0x00" prec="0x60" ttl="63" srcport="4938" dstport="5060" tcpflags="ACK" info="nf_ct_sip: dropping packet"
    2013:11:15-08:01:47 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.26" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:01:58 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.38" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:02:03 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60001" initf="eth1" srcmac="0:14:7f:aa:51:ac" dstmac="0:25:90:32:2c:5e" srcip="192.168.1.254" dstip="224.0.0.1" proto="2" length="36" tos="0x00" prec="0xc0" ttl="1" 
    2013:11:15-08:02:09 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.35" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:02:10 mail ulogd[4513]: id="2000" severity="info" sys="SecureNet" sub="packetfilter" name="Packet logged" action="log" fwrule="0" outitf="eth2" mark="0x1bd" app="445" srcmac="0:25:90:32:2c:5f" srcip="172.30.199.49" dstip="172.30.200.29" proto="6" length="1420" tos="0x00" prec="0x60" ttl="63" srcport="4938" dstport="5060" tcpflags="ACK" info="nf_ct_sip: dropping packet"
    2013:11:15-08:02:20 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.49" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:02:24 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.151" dstip="192.168.110.253" proto="17" length="142" tos="0x00" prec="0xc0" ttl="253" srcport="38205" dstport="5246" 
    2013:11:15-08:02:31 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.42" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:02:37 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60001" initf="ppp0" srcip="194.25.134.73" dstip="80.81.10.17" proto="6" length="40" tos="0x00" prec="0x00" ttl="249" srcport="25" dstport="38175" tcpflags="ACK RST" 
    2013:11:15-08:02:42 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.37" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:02:48 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.252" dstip="172.25.1.42" proto="17" length="306" tos="0x00" prec="0x00" ttl="62" srcport="32768" dstport="162" 
    2013:11:15-08:02:53 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.53" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:03:04 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.53" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:03:07 mail ulogd[4513]: id="2000" severity="info" sys="SecureNet" sub="packetfilter" name="Packet logged" action="log" fwrule="0" outitf="eth2" mark="0x21bd" app="445" srcmac="0:25:90:32:2c:5f" srcip="172.30.199.49" dstip="172.30.200.29" proto="6" length="1420" tos="0x00" prec="0x60" ttl="63" srcport="4532" dstport="5060" tcpflags="ACK" info="nf_ct_sip: dropping packet"
    2013:11:15-08:03:08 mail ulogd[4513]: id="2000" severity="info" sys="SecureNet" sub="packetfilter" name="Packet logged" action="log" fwrule="0" outitf="eth2" mark="0x1bd" app="445" srcmac="0:25:90:32:2c:5f" srcip="172.30.199.49" dstip="172.30.200.29" proto="6" length="1420" tos="0x00" prec="0x60" ttl="63" srcport="4532" dstport="5060" tcpflags="ACK" info="nf_ct_sip: dropping packet"
    2013:11:15-08:03:15 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.24" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:03:26 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.31" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:03:37 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.16" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:03:39 mail ulogd[4513]: id="2000" severity="info" sys="SecureNet" sub="packetfilter" name="Packet logged" action="log" fwrule="0" outitf="eth2" mark="0x1bd" app="445" srcmac="0:25:90:32:2c:5f" srcip="172.30.199.49" dstip="172.30.200.29" proto="6" length="1420" tos="0x00" prec="0x60" ttl="63" srcport="4532" dstport="5060" tcpflags="ACK" info="nf_ct_sip: dropping packet"
    2013:11:15-08:03:48 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.48" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:03:59 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60002" initf="eth2" outitf="ppp0" srcmac="4:c5:a4:f5:ce:40" dstmac="0:25:90:32:2c:5f" srcip="172.30.200.200" dstip="82.135.118.26" proto="1" length="84" tos="0x00" prec="0x00" ttl="62" type="8" code="0" 
    2013:11:15-08:04:08 mail ulogd[4513]: id="2000" severity="info" sys="SecureNet" sub="packetfilter" name="Packet logged" action="log" fwrule="0" outitf="eth2" mark="0x1bd" app="445" srcmac="0:25:90:32:2c:5f" srcip="172.30.199.49" dstip="172.30.200.29" proto="6" length="1420" tos="0x00" prec="0x60" ttl="63" srcport="4532" dstport="5060" tcpflags="ACK" info="nf_ct_sip: dropping packet"
  • so I did a 

    rmmod nf_nat_sip
    rmmod nf_conntrack_sip

    on the cli


    and suddenly the phones are coming up. Not quite sure what other side effects I might have because of this.. but it seems to be a bug in the nf_conntrack_sip module.
  • and now I´m seeing the RTCP Messages again:

    2013:11:15-14:35:20 mail ulogd[4513]: id="2001" severity="info" sys="SecureNet" sub="packetfilter" name="Packet dropped" action="drop" fwrule="60001" initf="ppp0" mark="0x31a4" app="420" srcip="217.10.77.21" dstip="80.81.12.71" proto="17" length="72" tos="0x18" prec="0xa0" ttl="57" srcport="54591" dstport="16839"
  • Are you sure that you checked the application control and intrusion prevention logs?  https://community.sophos.com/products/unified-threat-management/astaroorg/f/55/t/45956

    Cheers - Bob

    Sorry for any short responses.  Posted from my iPhone.