<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii">
<TITLE>Melding</TITLE>
<META content="MSHTML 6.00.2900.2180" name=GENERATOR></HEAD>
<BODY>
<DIV><FONT face=Arial size=2>
<DIV><SPAN class=089340900-26092004><FONT face=Arial
size=2>Hi,</FONT></SPAN></DIV>
<DIV><SPAN class=089340900-26092004><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=089340900-26092004><FONT face=Arial size=2>I'm doing some
testing with SER and recently noticed that some NOTIFY activity seems to
be going in an eternal loop at our server. 14 SIP NOTIFY Requests were
found to loop back and forth between host.domain.com and w.x.y.z where
host.domain.com is our server's FQDN and w.x.y.z its IP. The extract of
tcpdump output below shows how it looks like. Would greatly appreciate if
someone could help me understand what I am seeing; What can have caused this?
Could it be a result of bad routing logic?</FONT></SPAN></DIV>
<DIV><SPAN class=089340900-26092004><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=089340900-26092004><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=089340900-26092004>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.720999 host.domain.com.5060 > w.x.y.z.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 461 (DF) [tos 0x10] <?xml:namespace
prefix = o ns = "urn:schemas-microsoft-com:office:office"
/><o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721020 host.domain.com.5060 > w.x.y.z.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 584 (DF) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721032 host.domain.com.5060 > w.x.y.z.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 707 (DF) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721044 host.domain.com.5060 > w.x.y.z.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 830 (DF) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721056 host.domain.com.5060 > w.x.y.z.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 953 (DF) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721068 host.domain.com.5060 > w.x.y.z.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 1076 (DF) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721081 host.domain.com.5060 > w.x.y.z.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 1199 (DF) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721093 host.domain.com.5060 > w.x.y.z.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 1322 (DF) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721107 host.domain.com.5060 > w.x.y.z.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 1445 (DF) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721135 host.domain.com.5060 > w.x.y.z.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 1568 (frag 56776:1480@0+) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721158 host.domain.com.5060 > w.x.y.z.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 1691 (frag 56777:1480@0+) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721181 host.domain.com.5060 > w.x.y.z.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 1814 (frag 56778:1480@0+) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721204 host.domain.com.5060 > w.x.y.z.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 1937 (frag 56779:1480@0+) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721225 host.domain.com.5060 > w.x.y.z.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 2060 (frag 56780:1480@0+) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721415 w.x.y.z.5060 > host.domain.com.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 461 (DF) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721475 w.x.y.z.5060 > host.domain.com.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 584 (DF) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721585 w.x.y.z.5060 > host.domain.com.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 707 (DF) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721704 w.x.y.z.5060 > host.domain.com.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 830 (DF) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721843 w.x.y.z.5060 > host.domain.com.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 953 (DF) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.721981 w.x.y.z.5060 > host.domain.com.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 1076 (DF) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.722136 w.x.y.z.5060 > host.domain.com.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 1199 (DF) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.722301 w.x.y.z.5060 > host.domain.com.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 1322 (DF) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.722472 w.x.y.z.5060 > host.domain.com.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 1445 (DF) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.722507 w.x.y.z.5060 > host.domain.com.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 1568 (frag 56776:96@0+) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.722824 w.x.y.z.5060 > host.domain.com.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 1691 (frag 56777:224@0+) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.722961 w.x.y.z.5060 > host.domain.com.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 1814 (frag 56778:344@0+) [tos 0x10]
<o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=2><FONT
face=Arial>02:19:28.723165 w.x.y.z.5060 > host.domain.com.5060:<SPAN
style="mso-spacerun: yes"> </SPAN>udp 1937 (frag 56779:472@0+) [tos
0x10]<o:p></o:p></FONT></FONT></P></SPAN></DIV>
<DIV><SPAN class=089340900-26092004><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=089340900-26092004><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=089340900-26092004><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=089340900-26092004><FONT face=Arial
size=2>Regards,</FONT></SPAN></DIV>
<DIV><SPAN class=089340900-26092004><FONT face=Arial size=2>Mansur Ali
Abbasi</FONT></SPAN></DIV></FONT></DIV></BODY></HTML>